A low-cost separator enables a highly stable zinc anode by accelerating the de-solvation effect

Abstract

Aqueous zinc-ion batteries (ZIBs) are promising as the next-generation energy storage system due to their inherent safety and low cost, but challenges relating to H2O-induced side reactions and dendrite growth of the zinc anode are restricting its practical application. Herein, a low-cost separator (CNF + LMS) composed of cellulose nanofibers (CNF) and lithium magnesium silicate (LMS) has been prepared to eliminate the obstacles through accelerating the de-solvation process and facilitating the homogeneous zinc deposition. As verified by the experimental results and theoretical calculations, the battery with CNF + LMS separator shows a lower de-solvation activation energy (44.13 kJ mol−1) and faster de-solvation kinetics due to the superior water adsorption capacity of LMS molecules. Additionally, the CNF + LMS separator also presents superior wettability, large tensile strength, and excellent ionic conductivity, thus enabling dendrite‐free zinc deposition, long cycling life (1000 h at 1 mA cm−2; 500 h at 5 mA cm−2), superior Coulombic efficiency (99.12 % at 1 mA cm−2). The CNF + LMS separator, which cost as low as ¥ 6.36 per m2, can also be utilized in Zn||VO2 full battery and pouch cell to boost their electrochemical performance. Considering the facile preparation, low cost and practical feasibility, the CNF + LMS separator offers a new opportunity for developing practical ZIBs.