SiO2-Alginate-Based Gel Polymer Electrolytes for Zinc-Ion Batteries

Aqueous Zn-ion batteries (AZIBs) are quite promising energy sources. However, aqueous electrolytes present many challenges such as hydrolysis reactions, liquid leakage, Zn dendrites, and interfacial side reactions. To solve the above problems of aqueous electrolytes, in this study, a kind of SiO2-sodium alginate gel polymer electrolyte (SiO2-SA GPE) is prepared through a one-pot method. The SiO2-SA GPE possessed high ionic conductivity of 1.144 × 10−2S·cm−1and perfect mechanical strength. The Zn//LiFePO4batteries assembled with SiO2-SA GPE delivered a high discharge specific capacity of 89.9 mAh g−1(capacity retention = 74.9%) after 300 cycles at 1 C, which was much better than traditional liquid electrolytes (residual discharge capacity = 79.2 mAh g−1). Results of the rate performance and long cycle life of AZIBs proved that SiO2-SA GPE could effectively prevent zinc dendrites and side reactions, providing a feasible strategy for improving the performance of AZIBs.Keywords:aqueous zinc-ion batteries;sodium alginate;SiO2;gel polymer electrolytes;dendrite restriction