Controlled Synthesis of Bismuth Atomic Clusters on Porous TiO₂ Nanobiscuit with Ultrafast Sodium Storage

Abstract

Bismuth (Bi) has attracted widespread attention for sodium storage due to its high electronic/ionic conductivity, suitable reaction potential, and theoretical capacity (386 mAh g−1). However, Bi electrodes have a relatively high volumetric expansion ratio, which constrains their high capacity and affects the battery's cycle performance. Herein, a highly dispersed Bi atomic cluster is controllably prepared anchored on a porous TiO2 substrate through in situ segregation from Bi4Ti3O12 (TiO2/BiAC). The highly dispersed Bi clusters can serve as an “Ionic sponge” and accommodate more Na+ without causing excessive stress. Additionally, it aids in the decomposition of NaPF6, leading to the formation of a durable solid‐electrolyte interphase (SEI) layer rich in inorganic components. As expected, TiO2/BiAC exhibits excellent sodium storage performance in terms of cycling stability (346 mAh g−1 after 1000 cycles@ 1A g−1) and rate capability (231 mAh g−1 @ 100 A g−1). The pouch cell is further assembled and exhibits a specific capacity of 1.2 Ah after 200 cycles. This discovery presents a new method for developing efficient anode materials and is essential for steering the advancement of anode materials with fast charge–discharge capabilities.