Bonding synergy in In2TiO5 enables high-capacity fast lithium storage

Abstract

The growing need for lithium-ion batteries offering elevated energy density and rapid charging capabilities motivates the exploration of innovative high-capacity and high-rate anode materials. In this study, an In₂TiO₅ anode was developed by merging substantial lithium uptake from the conversion–alloying processes of In₂O₃ with rapid ion kinetics from the insertion process of TiO₂ via strategic octahedral reconfiguration. By capitalizing on the bonding synergy where longer In–O bonds enable efficient and large Li storage and shorter Ti–O bonds provide robust framework, Ti–O frameworks can effectively confine and stabilize the volume change of In species during (de)alloying processes. Leveraging the functionalities of Ti–O and In–O bonds, the In₂TiO₅ anode shows a stable capacity of 550 mAh g⁻¹ with a capacity retention of 82.1% after 600 cycles at 0.1 A g⁻¹, far exceeding that of In₂O₃ (290 mAh g⁻¹ after 260 cycles). Even at a high current density of 10 A g⁻¹, it maintains 160 mAh g⁻¹ with 80% retention after 1000 cycles. In situ and ex situ characterizations reveal that Li_xTiO₂ effectively confines the (de)alloying process of In species, which enables high structural integrity during (de)lithiation. This bonding synergy strategy using a unit-scale hybridization approach paves the way for engineering high-capacity and high-rate lithium-ion battery anodes.