Enabling intercalation-type TiNb 24 O 62 anode for sodium- and potassium-ion batteries via a synergetic strategy of oxygen vacancy and carbon incorporation

[摘要] 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 TiNb24O62−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 TiNb24O62−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 TiNb24O62−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.

[学科分类] 电力

[关键词] anode;defects;intercalation;potassium-ion battery;sodium-ion battery;sustainability