READ ME File For 'Dataset supporting the University of Southampton Doctoral Thesis: Hard Carbon Composites with Metal Oxides and Metal Nitrides for Sodium-ion Batteries.'

Dataset DOI: 10.5258/SOTON/D2650

ReadMe Author: Bowen Liu, University of Southampton [https://orcid.org/0000-0003-1328-7082]

This dataset supports the thesis entitled 'Hard Carbon Composites with Metal Oxides and Metal Nitrides for Sodium-ion Batteries'
AWARDED BY: Univeristy of Southampton
DATE OF AWARD: 2023

DESCRIPTION OF THE DATA
Complete dataset including all raw data used within the thesis publication 'Hard Carbon Composites with Metal Oxides and Metal Nitrides for Sodium-ion Batteries’, data is separated by chapter and includes relevant figure numbers. These figures are plotted using Microsoft Excel.


This dataset contains:

Chapter 1

Figure 1–8 (a) Correlation between d002 interlayer distance and specific capacity. (b) reduction/oxidation curves of annealed electrochemical graphite oxide at different current densities. Reproduced with permission,42 Copyright (2021) Elsevier.
Fig1-8a.txt: First column represents d002 interlayer distance and second column represents Specific capacity.

Figure 1–9 Typical reduction/oxidation curves of HC in sodium half-cells.
Fig1-9.txt: First two columns show the voltage and specific capacity for reduction and second two columns show the voltage and specific capacity for oxidation.

Figure 1–10 (a) Typical XRD pattern of HC and (b) relationship between d002 interlayer distance and carbonisation temperature.
Fig1-10a.txt: First column represents 2 theta degree and second column represents X-ray diffraction intensity.
Fig1-10b.txt: Each two columns show the carbonization temperature and d002 interlayer distance. Columns from left to right represent different reference.

Figure 1–11 (a) Typical Raman spectrum of HC and (b) relationship between ID/IG and carbonisation temperature.
Fig1-11a.txt: First column represents Raman shift and second column represents Raman scattering intensity.
Fig1-11b.txt: Each two columns show the carbonization temperature and ID/IG value. Columns from left to right represent different reference.

Figure 1–12 (a) Typical N2 adsorption–desorption isotherm of HC, (b) relationship between BET surface area and carbonisation temperature and (c) relationship between BET surface area and initial Coulombic efficiency.
Fig1-12a.txt: First column represents relative pressure and second column represents adsorption-desorption isotherms.
Fig1-12b.txt: Each two columns show the carbonization temperature and BET surface area. Columns from left to right represent different reference.
Fig1-12c.txt: Each two columns show the BET surface area and initial Coulombic efficiency. Columns from left to right represent different reference.

Figure 1–13 (a) Relationship between specific capacity and carbonisation temperature, (b) relationship between specific capacity and current density and (c) reduction/oxidation curves of the HC pyrolyzed from fir wood at current densities of 0.05 to 5 A g-1. Reproduced with permission,62 Copyright (2019) Elsevier.
Fig1-13a.txt: Each two columns show the carbonization temperature and specific capacity. Columns from left to right represent different reference.
Fig1-13b.txt: Each two columns show the current density and specific capacity. Columns from left to right represent different reference.


Chapter 3

Figure 3–1 SEM micrograph (a), XRD pattern (b), Raman spectrum (c), N2 adsorption–desorption isotherm (d) and pore size distribution (e) of the hard carbon used in this study.
Fig3-1b.txt: First column represents 2 theta degree and second column represents X-ray diffraction intensity.
Fig3-1c.txt: First column represents Raman shift and second column represents Raman scattering intensity.
Fig3-1d.txt: First column represents relative pressure and second column represents adsorption-desorption isotherms.
Fig3-1e.txt: First column represents pore width and second column represents incremental pore volume.

Figure 3–2 (a) Aqueous KCl solution conductivity as function of reciprocal of resistance. (b)Variation in the conductivity of a 1 mol dm−3 NaClO4 in 1:1 EC/DEC electrolyte with temperature.
Fig3-2a.txt: First column represents concentration of KCl solution, second column represents reciprocal of resistance and third column represents standard conductivity.
Fig3-2b.txt: First column represents temperature and second column represents conductivity.

Figure 3–4 (a) Nyquist plots of HC electrode at various temperature from 5 °C to 80 °C and frequency from 100 kHz to 0.1 HZ, with the high frequency part expanded in the inset; Equivalent circuit model of (b) sodium half cells cycled at 100 mA g−1 and (c) fresh sodium half cells.
Fig3-4a.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent Nyquist plots data of HC with increase temperature form 5 °C to 80 °C.

Figure 3–5 Cyclic capacity of HC at temperatures from 10 to 25 °C measured between 2 and 0.001 V (vs. Na+/Na) at 100 mA g−1 in sodium half-cells. The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig3-5.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency of HC. Columns from left to right represent HC battery with increase temperature form 10 °C to 25 °C.

Figure 3–6 Cyclic capacity of HC at temperatures (a) from 10 to 30 °C (b) from 40 to 80 °C measured between 2 and 0.001 V (vs. Na+/Na) at 100 mA g−1 in sodium half-cells. The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig3-6.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency of HC. Columns from left to right represent HC battery with increase temperature form 30 °C to 80 °C.

Figure 3–8 Voltage-capacity plots of galvanostatic cycling data at 100 mA g−1 current for HC at the 1st, 2nd, 5th, 10th and 20th cycle at (a) 10 °C, (b) 25 °C, (c) 40 °C, (d) 60 °C and (e) 80 °C.
Fig3-8a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent HC battery at 10 °C with increasing cycle number.
Fig3-8b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent HC battery at 25 °C with increasing cycle number.
Fig3-8c.txt: Each four columns show the voltage an
d specific capacity for reduction and oxidation. Columns from left to right represent HC battery at 40 °C with increasing cycle number.
Fig3-8d.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent HC battery at 60 °C with increasing cycle number.
Fig3-8e.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent HC battery at 80 °C with increasing cycle number.

Figure 3–9 CV profile of HC at temperatures from 15 to 70 °C at 1 mV s−1 scan rate between 3 and 0.01 V vs. Na+/Na (a) 1st cycle, (b) 2nd cycle, (c) 5th cycle and (d) 10th cycle.
Fig3-9a.txt: Each two columns show the voltage and current density in first cycle. Columns from left to right represent HC battery with increasing temperature.
Fig3-9b.txt: Each two columns show the voltage and current density in second cycle. Columns from left to right represent HC battery with increasing temperature.
Fig3-9c.txt: Each two columns show the voltage and current density in fifth cycle. Columns from left to right represent HC battery with increasing temperature.
Fig3-9d.txt: Each two columns show the voltage and current density in tenth cycle. Columns from left to right represent HC battery with increasing temperature.

Figure 3–10 Nyquist plots of HC electrode after different numbers of cycles at 100 mA g−1 (a) 10 °C, (b) 25 °C, (c) 40 °C and (d) 80 °C.
Fig3-10a.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent Nyquist plots data of HC at 10 °C with increase cycle number.
Fig3-10b.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent Nyquist plots data of HC at 25 °C with increase cycle number.
Fig3-10c.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent Nyquist plots data of HC at 40 °C with increase cycle number.
Fig3-10d.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent Nyquist plots data of HC at 80 °C with increase cycle number.


Figure 3–11 The relationship between Zre and ω-1/2 at low frequency with (a) freshly prepared and (b) cycled 19 cycles cells at 10, 25, 40 and 80 °C, (c) Na ion diffusion coefficients after 19 cycles at temperatures from 10 to 80 °C. and (d) dependence of natural logarithm of the average Na+ diffusion coefficient on reciprocal temperature.
Fig3-11a.txt: Each two columns show the real part impedance and reciprocal of root of frequency from fresh cell. Columns from left to right represent HC battery with increasing temperature.
Fig3-11b.txt: Each two columns show the real part impedance and reciprocal of root of frequency after 19 cycles. Columns from left to right represent HC battery with increasing temperature.
Fig3-11c.txt: First column represents temperature and second column represents Na+ diffusion coefficient. 
Fig3-11d.txt: First column represents reciprocal of temperature in Kelvin and second column represents Na+ diffusion coefficient. 

Figure 3–12 Rate capability of HC capacity and Coulombic efficiency at different current densities with various temperatures of 25, 40 and 60 °C. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig3-12.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency of HC. Columns from left to right represent HC battery with increase temperature.

Figure 3–13 Long-term cycling stability and Coulombic efficiency of HC with 25 and 40 °C. The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1.
Fig3-13.txt: First column represents cycle number. The next three columns represent reduction specific capacity, oxidation specific capacity and Coulombic efficiency of HC at 25 °C. The last three columns represent reduction specific capacity, oxidation specific capacity and Coulombic efficiency of HC at 40 °C

Figure 3–14 Nyquist plots of HC electrode after different numbers of cycles at 25 °C during long- term cycling.
Fig3-14.txt: Each two columns show the real part impedance and negative imaginary part impedance. Columns from left to right represent 1st, 5th, 10th, 20th, 50th, 100th, 150th and 200th cycle.

Figure 3–15 Voltage-capacity plots of galvanostatic cycling data at 100 mA g-1 current for HC at the 1st, 20th, 50th, 100th and 200th cycle at (a) 25 °C and (b) 40 °C.
Fig3-15a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent 1st, 20th, 50th, 100th and 200th cycle at 25 °C.
Fig3-15b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent 1st, 20th, 50th, 100th and 200th cycle at 40 °C.


Chapter 4

Figure 4–1 TGA analysis of Fe(acac)3 decomposition, examined by heating to 425 °C at 4 °C min-1 heating rate and 20 mL min-1 O2 plus 50 mL min-1 Ar flow.
Fig4-1.txt: First column represents temperature, second column represents time and third column represents relative mass.

Figure 4–2 XRD patterns of pure Fe2O3 (a) heated to 225, 250, 275, 300 and 325 °C for 2 hours with 4 °C min-1 and (b) heated to 300 °C for 2 hours at 1, 4, and 10 °C min-1.
Fig4-2a.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent pure Fe2O3 with increase calcination temperature.
Fig4-2b.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent pure Fe2O3 with increase heating rate.

Figure 4–3 TGA curves of (a) pure Fe2O3 (250-4-2) and (b) pure Fe2O3 (300-4-2), examined by heating to 425 °C with 4 °C min-1 heating rate and 20 mL min-1 O2 plus 50 mL min-1 Ar flow.
Fig4-3a.txt: First column represents temperature, second column represents time and third column represents relative mass.
Fig4-3b.txt: First column represents temperature, second column represents time and third column represents relative mass.

Figure 4–4 XRD patterns of 2.5%, 5%, 10%, 20%, 30%, 40% and 50% Fe2O3-HC (300-1-2).
Fig4-4.txt: Each two columns show 2 theta degree and represents X-ray diffraction intensity. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–6 (a) N2 adsorption-desorption curve and (b) pore size distribution of HC, 30% Fe(acac)3- HC and 30% Fe2O3-HC (300-1-2)
Fig4-6a.txt: Each two columns show relative pressure and adsorption-desorption isotherms. Columns from left to right represent unprocessed HC, 30% Fe(acac)3-HC and 30% Fe2O3-HC(300-1-2).
Fig4-6b.txt: Each two columns show pore width and incremental pore volume. Columns from left to right represent unprocessed HC, 30% Fe(acac)3-HC and 30% Fe2O3-HC(300-1-2).

Figure 4–7 Cycling performance of unprocessed HC, 2.5%, 5%, 10% and 20% Fe2O3-HC (300-1-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE.
Fig4-7.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–8 The voltage profile against reduction and oxidation specific capacity at (a) first cycle and (b) twentieth cycle of unprocessed HC, and 2.5%, 5%, 10% and 20% Fe2O3-HC (300-1-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-8a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.
Fig4-8b.txt:Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–9 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 2.5%, 5%, 10% and 20% Fe2O3-HC (300-1-2).
Fig4-9a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.
Fig4-9b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–10 (a) TGA analysis of FeC2O4·2H2O decomposition, examined by heating to 500 °C with 4 °C min-1 heating rate and 20 mL min-1 O2 plus 50 mL min-1 Ar flow (red line) and 70 mL min-1 Ar flow (blue line) and (b) XRD patterns of iron oxides after TGA measurement with different flow.
Fig4-10a.txt: Each two columns show the temperature and relative mass. First two columns represent with O2/Ar flow and last two columns present with Ar flow. 
Fig4-10b.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. First two columns represent with O2/Ar flow and last two columns present with Ar flow.

Figure 4–11 XRD patterns of Fe2O3-HC by heated at 120 °C, 160 °C and 200 °C for 12 hours with (a) 0.025 g and (b) 0.1 g FeC2O4·2H2O precursor.
Fig4-11a.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase hydrothermal temperature.
Fig4-11b.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent Fe2O3-HC composites with increase hydrothermal temperature.

Figure 4–12 Rietveld fits to the XRD patterns of (a) 5% Fe2O3-HC (120-12) (Rwp = 2.23%), (c) 5% Fe2O3-HC (160-12) (Rwp = 2.85%) and (e) 5% Fe2O3-HC (200-12) (Rwp = 3.00%) and SEM images of (b) 5% Fe2O3-HC (120-12) ,(d) 5% Fe2O3-HC (160-12) and (f) 5% Fe2O3-HC (200-12)
Fig4-12a.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.
Fig4-12c.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.
Fig4-12e.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.

Figure 4–13 TGA analysis of Fe2O3-HC (120-12), Fe2O3-HC (160-12) and Fe2O3-HC (200-12) with 0.1 g FeC2O4·2H2O precursor, examined by heating to 700 °C with 4 °C min-1 heating rate and 20 mL min-1 O2 plus 50 mL min-1 Ar flow.
Fig4-13.txt: Each two columns show the temperature and relative mass. Columns from left to right represent Fe2O3-HC composites with increase hydrothermal temperature.

Figure 4–14 (a) TGA analysis of unprocessed HC and HC (120-12), examined by heating to 500 °C with 4 °C min-1 heating rate with 50 mL min-1 Ar flow and (b) Raman spectra of unprocessed HC, HC (120-12) and HC (120-12-350-4).
Fig4-14a.txt: Each two columns show the temperature and relative mass. First two columns represent unprocessed HC and last two columns present HC(120-12).
Fig4-14b.txt: Each two columns show Raman shift and Raman scattering intensity. Columns from left to right represent unprocessed HC, HC(120-12) and HC(120-12-350-4).

Figure 4–15 (a) N2 adsorption-desorption curve and (b) pore size distribution of HC, 5% Fe2O3-HC (120-12), 5% Fe2O3-HC (120-12-300-4), 5% Fe2O3-HC (120-12-350-4) and 5% Fe2O3-HC (120-12-400-4).
Fig4-15a.txt: Each two columns show relative pressure and adsorption-desorption isotherms. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 
Fig4-15b.txt: Each two columns show pore width and incremental pore volume. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 

Figure 4–16 XRD patterns of 5% Fe2O3-HC (120-12), 5% Fe2O3-HC (120-12-300-4), 5% Fe2O3-HC (120-12-350-4) and 5% Fe2O3-HC (120-12-400-4).
Fig4-16.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 

Figure 4–18 Cycling performance of unprocessed HC, HC (120-12-350-4), 5% Fe2O3-HC (120-12), 5% Fe2O3-HC (120-12-300-4), 5% Fe2O3-HC (120-12-350-4) and 5% Fe2O3-HC (120-12- 400-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE.
Fig4-18.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(120-12-350-4), 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 

Figure 4–19 The voltage profile against reduction and oxidation specific capacity at (a) first cycle and (b) twentieth cycle of unprocessed HC, HC (120-12-350-4), 5% Fe2O3-HC (120-12), 5% Fe2O3-HC (120-12-300-4), 5% Fe2O3-HC (120-12-350-4) and 5% Fe2O3-HC (120-12- 400-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-19a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-4), 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 
Fig4-19b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-4), 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 

Figure 4–20 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 5% Fe2O3-HC (120-12), 5% Fe2O3-HC (120-12-300-4), 5% Fe2O3-HC (120-12-350-4) and 5% Fe2O3-HC (120-12-400-4).
Fig4-20a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature. 
Fig4-20b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2O3-HC with increase calcination temperature.

Figure 4–21 XRD patterns of 2.5% Fe2O3-HC (120-12-350-4), 5% Fe2O3-HC (120-12-350-4) and 10% Fe2O3-HC (120-12-350-4).
Fig4-21.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–22 TGA analysis of 2.5%, 5% and 10% Fe2O3-HC (120-12-350-4), examined by heating to 700 °C with 4 °C min-1 heating rate and 20 mL min-1 O2 plus 50 mL min-1 Ar flow.
Fig4-22.txt: Each two columns show the temperature and relative mass. Columns from left to right represent the Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–23 Cyclic performance of unprocessed HC, 2.5% Fe2O3-HC (120-12-350-4), 5% Fe2O3-HC (120-12-350-4) and 10% Fe2O3-HC (120-12-350-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE.
Fig4-23.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–24 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 2.5% Fe2O3-HC (120-12-350-4), 5% Fe2O3-HC (120-12-350-4) and 10% Fe2O3-HC (120-12-350-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-24a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.
Fig4-24b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–25 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 2.5% Fe2O3-HC (120-12-350-4), 5% Fe2O3-HC (120-12-350-4) and 10% Fe2O3-HC (120-12-350-4).
Fig4-25a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.
Fig4-25b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2O3-HC composites with increase Fe2O3 ratio.

Figure 4–26 (a) Long-term cycling performance and Coulombic efficiency. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE; and (b) Nyquist plots after 1st and 200th cycle of unprocessed HC, HC (120-12-350-4) and 5% Fe2O3-HC (120-12-350-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-26a.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(120-12-350-4) and 5%Fe2O3-HC(120-12-350-4).
Fig4-26b.txt: Each four columns show the real part impedance and negative imaginary part impedance for 1st and 200th cycle. Columns from left to right represent the unprocessed HC, HC(120-12-350-4) and 5%Fe2O3-HC(120-12-350-4).

Figure 4–27 Rate capability of unprocessed HC and 5% Fe2O3-HC (120-12-350-4) and Coulombic efficiency at different current densities. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig4-27.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC and 5%Fe2O3-HC(120-12-350-4).

Figure 4–28 Ex-situ XRD patterns of 5% Fe2O3-HC (120-12-350-4) before and after first cycling.
Fig4-28.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the initial electrode, after fully reduced and after fully oxidised.

Figure 4–29 XRD patterns of 5% Fe2N-HC produced at temperature 325, 350, 375,400 and 425 °C under a 0.1 L min-1 NH3 flow for 8 hours, 5% Fe2O3-HC (120-12) and unprocessed HC.
Fig4-29.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC, 5% Fe2O3-HC(120-12) and 5% Fe2N-HC with increase calcination temperature.

Figure 4–31 Raman spectra of unprocessed HC and HC (120-12-350-8).
Fig4-31.txt: Each two columns show Raman shift and Raman scattering intensity. Columns from left to right represent unprocessed HC and HC(120-12-350-8).

Figure 4–32 Cycling performance of unprocessed HC, HC (120-12-350-8), 5% Fe2N-HC (120-12- 325-8), 5% Fe2N-HC (120-12-350-8), 5% Fe2N-HC (120-12-375-8) and 5% Fe2N-HC (120-12-400-8). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE.
Fig4-32.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 5% Fe2N-HC with increase calcination temperature.


Figure 4–33The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (120-12-350-8), 5% Fe2N-HC (120-12-325-8), 5% Fe2N -HC (120-12-350-8), 5% Fe2N -HC (120-12-375-8) and 5% Fe2N -HC (120-12-400-8). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-33a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 5% Fe2N-HC with increase calcination temperature.
Fig4-33b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 5% Fe2N-HC with increase calcination temperature.

Figure 4–34 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (120-12-350-8), 5% Fe2N -HC (120-12-350-8), 5% Fe2N -HC (120- 12-375-8) and 5% Fe2N -HC (120-12-400-8).
Fig4-34a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 5% Fe2N-HC with increase calcination temperature.
Fig4-34b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 5% Fe2N-HC with increase calcination temperature.

Figure 4–35 XRD patterns of 2.5%, 5% and 10% Fe2N-HC (120-12-350-8).
Fig4-35.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and Fe2N-HC with increase Fe2N ratio.

Figure 4–36 Cycling performance of unprocessed HC, HC (120-12-350-8), 2.5% Fe2N-HC (120-12- 350-8), 5% Fe2N-HC (120-12-350-8) and 10% Fe2N-HC (120-12-350-8). Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE. The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-36.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and Fe2N-HC with increase Fe2N ratio.

Figure 4–37 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (120-12-350-8), 2.5% Fe2N- HC (120-12-350-8), 5% Fe2N-HC (120-12-350-8) and 10% Fe2N-HC (120-12-350-8). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-37a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and Fe2N-HC with increase Fe2N ratio.
Fig4-37b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and Fe2N-HC with increase Fe2N ratio.

Figure 4–38 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (120-12-350-8), 2.5% Fe2N-HC (120-12-350-8), 5% Fe2N-HC (120- 12-350-8) and 10% Fe2N-HC (120-12-350-8).
Fig4-38a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2N-HC with increase Fe2N ratio.
Fig4-38b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Fe2N-HC with increase Fe2N ratio.

Figure 4–39 (a) Long-term cycling performance and Coulombic efficiency of (Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show CE) and (b) Nyquist plots after 1st and 200th cycle of unprocessed HC, HC (120-12-350-8) and 10% Fe2N-HC (120-12-350-8). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig4-39a.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 10%Fe2N-HC(120-12-350-8).
Fig4-39b.txt: Each four columns show the real part impedance and negative imaginary part impedance for 1st and 200th cycle. Columns from left to right represent the unprocessed HC, HC(120-12-350-8) and 10%Fe2N-HC(120-12-350-8).

Figure 4–40 Rate capability of unprocessed HC and 10% Fe2O3-HC (120-12-350-8) and Coulombic efficiency at different current densities. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig4-40.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC and 10%Fe2N-HC(120-12-350-8).

Figure 4–41 Ex-situ XRD patterns of 5% Fe2N-HC (120-12-350-8) before and after first cycling.
Fig4-41.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the initial electrode, after fully reduced and after fully oxidised.


Chapter 5

Figure 5–1 XRD patterns of (a) 10% Ge3N4-HC (ALK) from 600 to 700 °C for 4 hours and (b) 10% Ge3N4-HC (ALK) from 600 to 650 °C for 8 hours.
Fig5-1a.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC, and 10% Ge3N4-HC with increase calcination temperature.
Fig5-1b.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC, and 10% Ge3N4-HC with increase calcination temperature.

Figure 5–2 Rietveld fits to the XRD patterns of (a) 10% Ge3N4-HC (650-4 ALK) (Rwp = 2.14%), (c) 10% Ge3N4-HC (650-8 ALK) (Rwp = 2.16%) and (e) 10% Ge3N4-HC (700-4 ALK) (Rwp = 4.09%) and SEM images of (b) 10% Ge3N4-HC (650-4 ALK), (d) 10% Ge3N4-HC (650-8 ALK) and (f) 10% Ge3N4-HC (700-4 ALK).
Fig5-2a.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.
Fig5-2c.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.
Fig5-2e.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.

Figure 5–4 (a) N2 adsorption-desorption curve and (b) pore size distribution of unprocessed HC, 10% Ge3N4-HC (600-4 ALK) and 10% Ge3N4-HC (700-4 ALK).
Fig5-4a.txt: Each two columns show relative pressure and adsorption-desorption isotherms. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(600-4 ALK) and 10%Ge3N4-HC(700-4 ALK).
Fig5-4b.txt: Each two columns show pore width and incremental pore volume. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(600-4 ALK) and 10%Ge3N4-HC(700-4 ALK).

Figure 5–5 XRD pattern of 10% Ge3N4-HC (acid) composites, with synthesis conditions as shown.
Fig5-5.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the precursor, 10%Ge3N4-HC(650-8 acid), 10%Ge3N4-HC(650-12 acid) and 10%Ge3N4-HC(675-8 acid).

Figure 5–6 Rietveld fits to the XRD patterns of (a) 10% Ge3N4-HC (650-12 acid) (Rwp = 2.84%) and (c) 10% Ge3N4-HC (675-8 acid) (Rwp = 3.40%) and SEM images of (b) 10% Ge3N4-HC (650-12 acid) and (d) 10% Ge3N4-HC (675-8 acid).
Fig5-6a.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.
Fig5-6c.txt: Columns from left to right represent 2 theta degree, experimental X-ray diffraction intensity, calculated X-ray diffraction intensity, background and difference.

Figure 5–8 Cyclic performance of (a) unprocessed HC, 10% Ge3N4-HC (600-4 ALK), 10% Ge3N4-HC (650-4 ALK), 10% Ge3N4-HC (700-4 ALK) and 10% Ge3N4-HC (650-8 ALK) and (b) unprocessed HC, 10% Ge3N4-HC (650-8 acid), 10% Ge3N4-HC (675-8 acid) and 10% Ge3N4-HC (650-12 acid). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-8a.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(600-4 ALK), 10%Ge3N4-HC(650-4 ALK), 10%Ge3N4-HC(700-4 ALK) and 10%Ge3N4-HC(650-8 ALK).
Fig5-8b.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(650-8 acid), 10%Ge3N4-HC(650-12 acid) and 10%Ge3N4-HC(675-8 acid).

Figure 5–9 The voltage profile against reduction and oxidation specific capacity at (a) first cycle and (b) twentieth cycle of unprocessed HC, 10% Ge3N4-HC (650-4 ALK), 10% Ge3N4-HC (650-8 ALK), 10% Ge3N4-HC (650-8 Acid) and 10% Ge3N4-HC (650-12 Acid). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1.
Fig5-9a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(650-4 ALK), 10%Ge3N4-HC(650-8 ALK), 10%Ge3N4-HC(650-8 acid) and 10%Ge3N4-HC(650-12 acid).
Fig5-9b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, 10%Ge3N4-HC(650-4 ALK), 10%Ge3N4-HC(650-8 ALK), 10%Ge3N4-HC(650-8 acid) and 10%Ge3N4-HC(650-12 acid).

Figure 5–10 XRD patterns of 2.5%, 5% and 10% Ge3N4-HC (650-12 acid).
Fig5-10.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the Ge3N4-HC composites with increase Ge3N4 ratio.

Figure 5–11 Raman spectra of unprocessed HC and HC (650-12 acid).
Fig5-11.txt: Each two columns show Raman shift and Raman scattering intensity. Columns from left to right represent unprocessed HC and HC(650-12 acid).

Figure 5–13 (a) TGA analysis of 2.5%, 5% and 10% Ge3N4-HC (650-12 acid), examined by heating to 700 °C with 4 °C min-1 heating rate with 20 mL min-1 O2 and 50 mL min-1 Ar flow. (b) XRD pattern of GeO2 obtained after TGA measurement.
Fig5-13a.txt: Each two columns show the temperature and relative mass. Columns from left to right represent the Ge3N4-HC composites with increase Ge3N4 ratio.
Fig5-13b.txt: First column represents 2 theta degree and second column represents X-ray diffraction intensity.

Figure 5–14 Cyclic performance of unprocessed HC, HC (650-12 acid), 2.5%, 5% and 10% Ge3N4-HC (650-12 acid). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-14.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(650-12 acid) and Ge3N4-HC composites with increase Ge3N4 ratio.

Figure 5–15 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b)the twentieth cycle of unprocessed HC and 2.5%, 5% and 10% Ge3N4-HC (650-12 acid). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1.
Fig5-15a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(650-12 acid) and Ge3N4-HC composites with increase Ge3N4 ratio.
Fig5-15b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(650-12 acid) and Ge3N4-HC composites with increase Ge3N4 ratio.

Figure 5–16 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC and 2.5%, 5% and 10% Ge3N4-HC (650-12 acid).
Fig5-16a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(650-12 acid) and Ge3N4-HC composites with increase Ge3N4 ratio.
Fig5-16b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(650-12 acid) and Ge3N4-HC composites with increase Ge3N4 ratio.

Figure 5–17 XRD patterns of unprocessed HC, 20% Nb(ON)x-HC precursor, 20% Nb(ON)x-HC (500- 2), 20% Nb(ON)x-HC (550-2), 20% Nb(ON)x-HC (600-2), 20% Nb(ON)x-HC (650-2) and 20% Nb(ON)x-HC (700-2).
Fig5-17.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC, precursor and 20% Nb(ON)x-HC composites with increase calcination temperature.

Figure 5–18 Cycling performance of unprocessed HC, 20% Nb(ON)0.425-HC (500-2), 20% Nb(ON)0.425-HC (550-2), 20% Nb(ON)0.425-HC (600-2) and 20% Nb(ON)0.425-HC (650-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-18.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase calcination temperature.

Figure 5–19 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 20% Nb(ON)0.425-HC (500-2), 20% Nb(ON)0.425-HC (550-2), 20% Nb(ON)0.425-HC (600-2) and 20% Nb(ON)0.425-HC (650-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1.
Fig5-19a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase calcination temperature.
Fig5-19b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase calcination temperature.

Figure 5–20 XRD patterns of unprocessed HC and 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2).
Fig5-20.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.

Figure 5–22 (a) N2 adsorption-desorption curve and (b) pore size distribution of unprocessed HC, HC (550-2), 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2).
Fig5-22a.txt: Each two columns show relative pressure and adsorption-desorption isotherms. Columns from left to right represent the unprocessed HC, HC(550-2) and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.
Fig5-22b.txt: Each two columns show pore width and incremental pore volume. Columns from left to right represent the unprocessed HC, HC(550-2) and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.

Figure 5–23 (a) TGA analysis of 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2), examined by heating to 700 °C with 4 °C min-1 heating rate with 20 mL min-1 O2 and 50 mL min-1 Ar flow and (b) XRD pattern of Nb2O5 obtained after TGA measurement.
Fig5-23a.txt: Each two columns show the temperature and relative mass. Columns from left to right represent the Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.
Fig5-23b.txt: First column represents 2 theta degree and second column represents X-ray diffraction intensity.

Figure 5–24 Cyclic performance of unprocessed HC, HC (550-2), 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-24.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(550-2) and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.

Figure 5–25 The voltage profile against reduction and oxidation specific capacity at (a) first cycle and (b) twentieth cycle of unprocessed HC, HC (550-2), 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 100 mA g-1.
Fig5-25a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(550-2) and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.
Fig5-25a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(550-2) and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.

Figure 5–26 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (550-2), 2.5%, 5%, 10% and 20% Nb(ON)0.425-HC (550-2).
Fig5-26a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.
Fig5-26b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and Nb(ON)0.425-HC composites with increase Nb(ON)0.425 ratio.

Figure 5–27 XRD patterns of unprocessed HC, 10% VN-HC (425-4), 10% VN-HC (450-4), 10% VN-HC (475-4), 10% VN-HC (500-4) and 10% VN-HC (525-4).
Fig5-27.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and VN-HC composites with increase calcination temperature.


Figure 5–29 Cycling performance of unprocessed HC, 10% VN-HC (425-4), 10% VN-HC (450-4), 10% VN-HC (475-4), 10% VN-HC (500-4) and 10% VN-HC (525-4). The sodium half- cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-29.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC and VN-HC composites with increase calcination temperature.

Figure 5–30 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, 10% VN-HC (425-4), 10% VN-HC (450-4), 10% VN-HC (475-4), 10% VN-HC (500-4) and 10% VN-HC (525-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig5-30a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and VN-HC composites with increase calcination temperature.
Fig5-30b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and VN-HC composites with increase calcination temperature.

Figure 5–31 XRD patterns of unprocessed HC, 2.5%, 5%, 10% and 20% VN-HC(450-4).
Fig5-31.txt: Each two columns show 2 theta degree and X-ray diffraction intensity. Columns from left to right represent the unprocessed HC and VN-HC composites with increase VN ratio.

Figure 5–33 (a) N2 adsorption-desorption curve and (b) pore size distribution of unprocessed HC, 2.5%, 5%, 10% and 20% VN-HC (450-4).
Fig5-33a.txt: Each two columns show relative pressure and adsorption-desorption isotherms. Columns from left to right represent the unprocessed HC and VN-HC composites with increase VN ratio.
Fig5-33b.txt: Each two columns show pore width and incremental pore volume. Columns from left to right represent the unprocessed HC and VN-HC composites with increase VN ratio.

Figure 5–34 TGA analysis of 2.5%, 5%, 10% and 20% VN-HC (450-4), examined by heating to 700 °C with 4 °C min-1 heating rate with 20 mL min-1 O2 and 50 mL min-1 Ar flow and (b) XRD pattern of V2O5 obtained after TGA measurement.
Fig5-34a.txt: Each two columns show the temperature and relative mass. Columns from left to right represent the VN-HC composites with increase VN ratio.
Fig5-34b.txt: First column represents 2 theta degree and second column represents X-ray diffraction intensity.

Figure 5–35 Cycling performance of unprocessed HC, HC (450-4), 2.5%, 5%, 10% and 20% VN-HC (450-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1. Closed circle symbols show reduction capacity, open circle symbols show oxidation capacity and closed triangle symbols show Coulombic efficiency.
Fig5-35.txt: First column represents cycle number. Next each three columns show the reduction specific capacity, oxidation specific capacity and Coulombic efficiency. Columns from left to right represent the unprocessed HC, HC(450-4) and VN-HC composites with increase VN ratio.

Figure 5–36 The voltage profile against reduction and oxidation specific capacity at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (450-4), 2.5%, 5%, 10% and 20% VN-HC (450-4). The sodium half-cells were cycled between 0.001 and 2 V (vs. Na/Na+) at 50 mA g-1.
Fig5-36a.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(450-4) and VN-HC composites with increase VN ratio.
Fig5-36b.txt: Each four columns show the voltage and specific capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC, HC(450-4) and VN-HC composites with increase VN ratio.

Figure 5–37 Differential capacity plots at (a) the first cycle and (b) the twentieth cycle of unprocessed HC, HC (450-4), 2.5%, 5%, 10% and 20% VN-HC (450-4).
Fig5-37a.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and VN-HC composites with increase VN ratio.
Fig5-37b.txt: Each four columns show the voltage and differential capacity for reduction and oxidation. Columns from left to right represent the unprocessed HC and VN-HC composites with increase VN ratio.


Chapter 6

Figure 6–1 Summary of the capacities at the first and twentieth cycle of (a) unprocessed HC, 2.5% γ-Fe2O3-HC, 5% α-Fe2O3-HC, 10% Fe2N-HC and 5% VN-HC with 50 mA g-1 current density and (b) unprocessed HC, 5% Ge3N4-HC and 5% Nb(ON)0.425-HC with 100 mA g-1 current density. Closed circle symbols show reduction capacity and open circle symbols show oxidation capacity.
Fig6-1a.txt: First column represents cycle number. Next each two columns show the reduction and oxidation specific capacity. Columns from left to right represent the unprocessed HC, 2.5% γ-Fe2O3-HC, 5% α-Fe2O3-HC, 10% Fe2N-HC and 5% VN-HC.
Fig6-1b.txt: First column represents cycle number. Next each two columns show the reduction and oxidation specific capacity. Columns from left to right represent the unprocessed HC, 5% Ge3N4-HC and 5% Nb(ON)0.425-HC.




Date of data collection: September 2018 - March 2022

Information about geographic location of data collection: 

Licence:
CC-BY

Related projects/Funders:
N/A

Related publication:
B. Liu, A. L. Hector, W. O. Razmus and R. G. A. Wills, Batteries, 2022, 8, 108.


Date that the file was created: May, 2023