Interlayer Engineering of α‐MoO<sub>3</sub> Modulates Selective Hydronium Intercalation in Neutral Aqueous Electrolyte
Haozhe Zhang, Weixing Wu, Qiyu Liu, Fan Yang, Xin Shi, Xiaoqing Liu, Minghao Yu, Xihong Lu
Abstract
Abstract Among various charge‐carrier ions for aqueous batteries, non‐metal hydronium (H 3 O + ) with small ionic size and fast diffusion kinetics empowers H 3 O + ‐intercalation electrodes with high rate performance and fast‐charging capability. However, pure H 3 O + charge carriers for inorganic electrode materials have only been observed in corrosive acidic electrolytes, rather than in mild neutral electrolytes. Herein, we report how selective H 3 O + intercalation in a neutral ZnCl 2 electrolyte can be achieved for water‐proton co‐intercalated α‐MoO 3 (denoted WP‐MoO 3 ). H 2 O molecules located between MoO 3 interlayers block Zn 2+ intercalation pathways while allowing smooth H 3 O + intercalation/diffusion through a Grotthuss proton‐conduction mechanism. Compared to α‐MoO 3 with a Zn 2+ ‐intercalation mechanism, WP‐MoO 3 delivers the substantially enhanced specific capacity (356.8 vs. 184.0 mA h g −1 ), rate capability (77.5 % vs. 42.2 % from 0.4 to 4.8 A g −1 ), and cycling stability (83 % vs. 13 % over 1000 cycles). This work demonstrates the possibility of modulating electrochemical intercalating ions by interlayer engineering, to construct high‐rate and long‐life electrodes for aqueous batteries.