The synergistic effect of PVA-based gel electrolyte and Cu2+ on the optimization of zinc anode

Abstract

In practical applications, rechargeable aqueous zinc ion batteries (AZIBs) face challenges such as battery leakage and pronounced dendrite growth on the zinc anode, primarily due to the absence of superior electrolyte materials. These issues significantly impact the longevity and reliability of AZIBs. To address these problems, we have designed a novel Zn(CF3SO3)2-polyvinyl alcohol(PVA)-Cu(CF3SO3)2 gel electrolyte(CPVF) consisting of poly(vinyl alcohol) (PVA) synergized with Cu2+. This innovative electrolyte not only effectively prevents leakage, a common issue with conventional electrolytes, but also promotes the uniform deposition of zinc ions. The ordered porous structure within the PVA matrix restricts the uncontrolled growth of zinc dendrites, while the Cu2+ in the gel offer a multitude of uniform zinc-philic sites in the form of Cu0 on the zinc anode. As a result, the Zn//CPVF//Zn symmetrical battery demonstrates remarkable cycling stability, with a lifespan exceeding 1200 h at 1 mA/cm2 and 0.5 mAh/cm2. Furthermore, the Zn//CPVF//V2O5 full cell retains 82.6 % of its capacity after 500 cycles at 1 A/g. The research results provide guidance for the design and optimization of high-performance and low-cost AZIBs electrolyte materials.