Na–CO₂ battery with NASICON-structured solid-state electrolyte

Utilizing CO₂ as cathode gas, Na–CO₂ battery has been intensively studied due to its potential application in the exploration of Mars, where CO₂ takes up 96% of the atmosphere. However, evaporation of the flammable liquid electrolyte restricts the practical application of the Na–CO₂ battery. Herein, a solid-state Na–CO₂ battery has been fabricated with the help of a plastic crystal electrolyte and kinetically stable interphase. The succinonitrile-based plastic crystal electrolyte interphase makes an intimate contact between Na₃Zr₂Si₂PO₁₂(NZSP) and cathode, thereby promotes the interfacial charge transfer. Simultaneously, the kinetically stable interphase on the anode side is revealed by the cooperation of theoretical calculation and experiments. The kinetically stable interphase protects the NZSP from the continuous interfacial parasitic reaction. The as-proposed solid-state Na–CO₂ battery delivers a life span of 50 cycles at 100 mA g⁻¹ with a potential gap of 1.4 V. This study makes solid-state electrolyte Na–CO₂ battery an attractive prospect in future applications.