Enabling intercalation-type TiNb₂₄O₆₂ anode for sodium- and potassium-ion batteries via a synergetic strategy of oxygen vacancy and carbon incorporation

Abstract

The key to develop earth-abundant energy storage technologies sodium- and potassium-ion batteries (SIBs and PIBs) is to identify low-cost electrode materials that allow fast and reversible Na⁺/K⁺ intercalation. Here, we report an intercalation-type material TiNb₂₄O₆₂ as a versatile anode for SIBs and PIBs, via a synergistic strategy of oxygen vacancy and carbon incorporation to enhance ion and electron diffusion. The TiNb₂₄O_62−x/reduced graphene oxide (rGO) composite anode delivers high reversible capacities (130 mA h g⁻¹ for SIBs and 178 mA h g⁻¹ for PIBs), great rate performance (54 mA h g⁻¹ for SIBs and 37 mA h g⁻¹ for PIBs at 1 A g⁻¹), and superior cycle stability (73.7% after 500 cycles for SIBs and 84% after 300 cycles for PIBs). The performance is among the best results of intercalation-type metal oxide anodes for SIBs and PIBs. The better performance of TiNb₂₄O_62−x/rGO in SIBs than PIBs is due to the better reaction kinetics of the former. Moreover, mechanistic study confirms that the redox activity of Nb4⁺/5⁺ is responsible for the reversible intercalation of Na⁺/K⁺_. Our results suggest that TiNb₂₄O_62−x/rGO is a promising anode for SIBs and PIBs and may stimulate further research on intercalation-type compounds as candidate anodes for large ion batteries.

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Identifiers

ORCID for Ajay Piriya Vijaya Kumar Saroja: orcid.org/0000-0002-7412-6269

ORCID for Zhipeng Wang: orcid.org/0009-0004-1940-1047

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