Cellulose/sodium alginate gel electrolyte membranes with synergistic hydrogen bonding and metal ion coordination networks for high performance aqueous zinc-ion batteries

Cellulose has outstanding potential for application in energy storage batteries due to its high temperature resistance, high electrolyte affinity, renewability, and suppression of the shuttle effect, but single cellulose membranes still suffer from problems such as inhomogeneous pore distribution and unstable three-dimensional network structure. In this study, a green and sustainable regenerative cellulose (RC)/sodium alginate (SA) gel electrolyte membrane is developed by sol-gel process, the double crosslinked network scaffold centered on Zn 2+ was constructed by the synergistic hydrogen-bonding and metal ion- coordination network, the stable and uniform pore structure was also formed. The obtained RC-SA gel electrolyte membrane exhibits outstanding performance, featuring a dual crosslinked network with abundant pore structure and numerous polar groups that effectively enhance Zn 2+ transport, significantly improving battery cycling performance. The corresponding RC-SA gel electrolyte membrane demonstrates high ionic conductivity (6.30 mS·cm −1 ) and Zn 2+ transference number (0.66), leading to excellent reversible capacity (159 mA·h·g −1 ) and self-discharge suppression capability (maintaining 99.2 % of capacity after a 24 h standstill) in Zn//V 2 O 5 full-cell. The coulombic efficiency and cycling stability of the Zn//Cu half-cell and Zn//Zn symmetric cell using RC-SA gel electrolyte membrane outperforms that of the glass fiber separator, highlighting its multifunctionality and potential applications.