Simultaneous Inhibition of Vanadium Dissolution and Zinc Dendrites by Mineral-Derived Solid-State Electrolyte for...

Designing solid electrolyte is deemed as an effective approach to suppress the side reaction of zinc anode and active material dissolution of cathodes in liquid electrolytes for zinc metal batteries (ZMBs). Herein, kaolin is comprehensively investigated as raw material to prepare solid electrolyte (KL-Zn) for ZMBs. As demonstrated, KL-Zn electrolyte is an excellent electronic insulator and zinc ionic conductor, which presents wide voltage window of 2.73 V, high ionic conductivity of 5.08 mS cm^-1, and high Zn²⁺ transference number of 0.79. For the Zn//Zn cells, superior cyclic stability lasting for 2200 h can be achieved at 0.2 mA cm^-2. For the Zn//NH₄V₄O₁₀ batteries, stable capacity of 245.8 mAh g^-1 can be maintained at 0.2 A g^-1 after 200 cycles along with high retention ratio of 81 %, manifesting KL-Zn electrolyte contributes to stabilize the crystal structure of NH₄V₄O₁₀ cathode. These satisfying performances can be attributed to the enlarged interlayer spacing, zinc (de)solvation-free mechanism and fast diffusion kinetics of KL-Zn electrolyte, availably guaranteeing uniform zinc deposition for zinc anode and reversible zinc (de)intercalation for NH₄V₄O₁₀ cathode. Additionally, this work also verifies the application possibility of KL-Zn electrolyte for Zn//MnO₂ batteries and Zn//I₂ batteries, suggesting the universality of mineral-based solid electrolyte.