Amorphous TiO₂ ultrathin nanosheet for stable high-rate lithium storage

Abstract

The use of intercalation-type metal oxides as anode materials in rechargeable lithium-ion batteries is appealing due to their reduced risk of Li plating at low voltages. However, their implementation for fast-charging applications is limited by their lower energy and power density, as well as cycling instability. Herein, we present an amorphous TiO₂ nanosheet that exhibits exceptional cycling stability with a high capacity of 231 mA <b>·</b> h <b>·</b> g⁻¹ after 200 cycles at 500 mA <b>·</b> g⁻¹ and 156.7 mA <b>·</b> h <b>·</b> g⁻¹ after 1000 cycles at a high current density of 6 A <b>·</b> g⁻¹. We attribute the enhanced rate performance to the amorphous nature with high isotropy, which facilitates low energy migration paths and ion availability and can accommodate large changes in volume. This work suggests that amorphization represents a promising strategy for developing unconventional metal oxide electrode materials with high-rate performance.