Dendrite-free zinc anode enable via amidoxime functional groups in gel polymer electrolytes for aqueous zinc metal batteries

Aqueous zinc metal batteries (AZMBs) caught significant attention because of their simple manufacturing processes, low cost, and excellent safety profiles. However, the use of liquid electrolyte in AZMBs would lead to selfcorrosion, hydrogen evolution reaction caused by water decomposition and zinc dendrite growth. These would result in low Coulombic efficiency, poor cycling performance, and cell short-circuiting, limiting the development of AZMBs. Herein, a gel polymer electrolyte (GPE) was designed by introducing polymers of intrinsic microporosity (PIMs) and subjecting the polymer to amidoximation (AO-PIM-1) using bacterial cellulose (BC) as a support membrane to obtain the desired AO-PIM-1/BC GPE. The C=N in the amidoxime functional group in the GPE coordinates with Zn2+ to promote ion transport and uniform deposition of Zn. In addition, the hydrophilic groups, -NH2 and -OH, reduced the energy required for the desolvation of hydrated Zn2+ inducing in a wide electrochemical stability window (2.42 V). Therefore, the Zn//Zn cells that incorporate the AO-PIM-1/BC GPE exhibit a cycle life of up to similar to 1100h and a Coulombic efficiency of 99.97 %. Furthermore, Zn//alpha-MnO2 retains 85 % of its initial capacity after 400 charge/discharge cycles (0.5C) and realizes a dendrite-free Zn anode. This AOPIM-1/BC GPE provides an effective strategy for protecting the Zn anode in AZMBs.