A Janus Membrane with Asymmetrical Proton Transport for Cross-Communication Harmony for an Extreme Lean Electrolyte Zn–V Battery
Chaozheng Liu, Bo Lin, Zhenglin Li, Chuhang Liu, Yao Wang, Weimin Chen, Wangwang Xu, Mei‐Chun Li, Shu Hong, Lei Zhang, Pei Yang, Min Wang, Kangning Zhao, Changtong Mei
Abstract
The Zn metal anode demands a reduction in water activity and proton concentration to prevent undesirable side reactions, while the V-based cathode necessitates water as a “lubricant” and protons as intercalation guests, presenting a challenge in balancing these needs. Herein, we report a Janus membrane with asymmetrical proton transport for cross-communication harmony in Zn–V batteries, designed to harmonize these contrasting requirements. The MXene-rich phase blocks the proton/water transport through the F-termination site and effectively suppresses dendrite formation through epitaxial growth. Meanwhile, the proton selective cellulose-rich phase (H + /Zn 2+ selectivity of over 21) stabilizes the cathode/electrolyte interface by capturing dissolved vanadium and enhancing proton intercalation into the cathode. This designed Janus membrane enables a practical Zn–V full battery at a high depth of discharge of 66.7% and extreme lean electrolyte (1 g/Ah) conditions, enabling the high energy zinc battery (214.8 Wh/kg electrode ). Our approach introduces a sustainable separator for long-lasting, high-performance zinc metal batteries.