A Durable Solid‐State Na–CO2 Battery with Solid Composite Electrolyte Na3.2Zr1.9Ca0.1Si2PO12–PVDF‐HFP

Abstract

Na–CO2 batteries are important devices for immobilizing CO2 and storing renewable energy. However, the Na–CO2 batteries with liquid electrolytes have the issues of electrolyte volatilization and poor cyclability. Herein, a composite solid‐state electrolyte consisting of Ca‐doped Na3Zr2Si2PO12 and polyvinylidene fluoride‐co‐hexafluoropropylene (PVDF‐HFP) is synthesized. The solid composite electrolyte Na3.2Zr1.9Ca0.1Si2PO12–PVDF‐HFP shows a high ionic conductivity of 1.32 × 10−4 S cm−1 at room temperature and a broad electrochemical window up to 5.15 V, as well as excellent durability. The assembled solid‐state Na–CO2 battery with this composite electrolyte delivers a high discharge‐specific capacity up to 3320 mA h g−1 and excellent cycling stability.