Unlocking High-Performance Ammonium-Ion Batteries: Activation of In-Layer Channels for Enhanced Ion Storage and Migration

作者：Zhang, Xiangyong; Wei, Hua; Ren, Baohui; Jiang, Jingjing; Qu, Guangmeng; Yang, Jinlong; Chen, Guangming; Li, Hongfei^*; Zhi, Chunyi^*; Liu, Zhuoxin^*

来源：Advanced Materials, 2023, 35(40).

DOI：10.1002/adma.202304209

• ammonium-ion batteries
• aqueous batteries
• energy storage mechanisms
• in-layer channels
• layered electrodes

Ammonium-ion batteries, leveraging non-metallic ammonium ions, have arisen as a promising electrochemical energy storage system; however, their advancement has been hindered by the scarcity of high-performance ammonium-ion storage materials. In this study, an electrochemical phase transformation approach is proposed for the in situ synthesis of layered VOPO4 & BULL;2H(2)O (E-VOPO) with predominant growth on the (200) plane, corresponding to the tetragonal channels on the (001) layers. The findings reveal that these tetragonal in-layer channels not only furnish NH4+ storage sites but also enhance transfer kinetics by providing rapid cross-layer migration pathways. This crucial aspect has been largely overlooked in previous studies. The E-VOPO electrode exhibits exceptional ammonium-ion storage performance, including significantly increased specific capacity, enhanced rate capability, and robust cycling stability. The resulting full cell can be stably operated for 12 500 charge-discharge cycles at 2 A g(-1) for over 70 days. The proposed approach offers a new strategy for meticulously engineering electrode materials with facilitated ion storage and migration, thereby paving the way for developing more efficient and sustainable energy storage systems.