Gel Electrolyte with Excellent Zinc-Ion Conductivity for Achieving Highly Reversible Zinc Anodes

The rapid development of large-scale energy storage systems urgently demands safe, efficient, and green battery technologies. Aqueous zinc-ion batteries (ZIBs) have emerged as promising candidates owing to their environmental friendliness, low cost, and high theoretical capacity. However, challenges such as dendrite growth, hydrogen evolution, and poor cycling stability severely hinder their practical application. Here, we report a novel PVA/CMC/PEG-SiO2 (PCPSiO2) gel electrolyte that achieves exceptional ionic conductivity (46.24 mS cm–1) and zinc ion transference number (0.89). The abundant functional groups in the gel matrix induced the uniform deposition of Zn during the plating/stripping process, which effectively inhibited the dendrite growth. The results demonstrate that the Zn∥Zn symmetric cell can cycle for over 3500 h at 0.5 mA cm–2 and over 8500 h at 0.1 mA cm–2. Additionally, it maintains stable cycling for over 1100 h even under high capacity (6 mAh). Furthermore, the full cell using V2O5/CNT cathodes exhibits excellent rate performance (193 mAh g–1 at 9 A g–1) and superior cycling stability (87% capacity retention after 1000 cycles at 3 A g–1). This study provides new insights and technical support for improving the performance of zinc-ion batteries, holds great promise for advancing their commercial applications, and is expected to make a significant contribution to the development of more environmentally friendly and efficient energy storage solutions.