Amorphization Stabilizes Te‐Based Aqueous Batteries via Confining Free Water
Yanyan Zhang, Wanhai Zhou, Wanhai Zhou, Boya Wang, Tengsheng Zhang, Xiaoyu Yu, Xinran Li, Gaoyang Li, Hongrun Jin, Minghua Chen, Wei Li, Dongyuan Zhao, Xin Liu, Xin Liu, Dongliang Chao
Abstract
Abstract Tellurium (Te), with its rich valence states (−2 to +6), could endow aqueous batteries with potentially high specific capacity. However, achieving complete and stable hypervalent Te 0 /Te 4+ electrochemistry in an aqueous environment poses significant challenges, owing to the sluggish reduction kinetics, easy dissolution of Te 4+ species, and a controversial energy storage mechanism. Herein, we demonstrate a crystallographic regulation strategy for robust aqueous Te redox electrochemistry. With strong hydrogen bonding, NH 4 Ac confines free water, prompting the amorphization of TeO 2 (a‐TeO 2 ). In situ synchrotron characterization, spectroscopy analysis, electrochemical evaluation, and theoretical calculations reveal a specific 4 e − solid‐solid transition pathway (Te to a‐TeO 2 ) with accelerated diffusion and charge transfer kinetics, attributed to a closer unoccupied electron orbital to the Fermi level and a reduced water desorption energy barrier in a‐TeO 2 . Impressively, the a‐TeO 2 /Te redox exhibits a high reversible capacity of 834 mAh g −1 (99% of Te redox utilization), superior rate performance (644 mAh g −1 at 10 A g −1 ), and an ultralong lifespan (over 3000 cycles). These findings prove a new tactic to advance aqueous Te redox electrochemistry toward high‐energy aqueous batteries.