H<sub>2</sub>O‐Boosted MgProton Collaborated Energy Storage for Rechargeable Mg‐Metal Batteries
Chaoran Yang, Zhichen Pu, Zhenfei Jiang, Xiaowen Gao, Kewei Wang, Shiyang Wang, Yuming Chai, Qi Li, Xue‐Jun Wu, Yunlong Xiao, Dongsheng Xu
Abstract
Abstract Rechargeable magnesium batteries (RMBs) are a kind of energy storage system with high safety, low cost, and high volumetric energy density. In general perception, H 2 O will passivate the Mg‐metal anode. But herein, a coordination–hydrolysis strategy is developed, in which H 2 O can be used as an additive to produce dissociated H + . Moreover, MgH + energy storage mechanism is discovered on CuSe cathode, which helps the specific capacity and energy density enhance to 480 mAh g −1 and 413 Wh kg −1 , respectively. This coordination–hydrolysis strategy also promotes the conductivity and electron transfer ability of electrolyte. Consequently, the specific capacity can remain 247 mAh g −1 even at 2 A g −1 . MgH + energy storage route gets rid of massive cathode material, and protons have the smallest size and lightest weight, whose theoretical energy density can reach 4230 Wh kg −1 . The results elucidated here provide a new route for energy‐dense RMBs.