K<sub>x</sub>Na<sub>y</sub>H<sub>(2‐x‐y)</sub>Ti<sub>2</sub>O<sub>5</sub> for High‐Performance Lithium‐Ion Battery Anode with Li Dendrites‐Free Mechanism, Zero‐Strain Characteristic
Chaohui Yuan, Miao Wang, Junjun Wang, Wentian Chen, Na Li, Yuqian Fan, Zhipeng Ma, Wenfeng Guo, Liqiang Mai
Abstract
Abstract Conventional Li‐ion batteries equipped with graphite anodes suffer from poor rate performance and the risk of lithium dendrites, which constrain scale‐up applications. Among the promising candidates, spinel‐type Li 4 Ti 5 O 12 is still subjected to low theoretical specific capacity, high working potential, and poor diffusion properties. Herein the K x Na y H (2‐x‐y) Ti 2 O 5 product is provided by reconstructing the chemical bonding idea, which exhibits enhanced specific capacity (323 mAh g −1 ), lower working potential (major capacity contribution < 1.5 V vs Li + /Li), higher diffusion coefficient (10 −8.5 –10 −5 cm 2 s −1 ), and long cycle stability. Further in/ex situ studies show that these excellent properties can be attributed to the combination of high capacitive contribution, unique “switching mechanism” to avoid lithium dendrite generation, and the zero‐strain properties. The findings provide new ideas and opportunities for the development of next generation titanate anode materials with desirable electrochemical properties.