Realizing long-cycling solid-state Li–CO2 batteries using Zn-doped LATP ceramic electrolytes

Abstract

Lithium–carbon dioxide (Li–CO2) batteries with high theoretical energy density and carbon dioxide conversion ability are considered as the next generation of energy storage devices for solving electric vehicle range anxiety and reducing the greenhouse effect. However, the volatilization and leakage of traditional liquid organic electrolytes and the short circuit caused by the penetration of the lithium dendrite anode induce serious cycle and safety problems, hindering the commercial application of Li–CO2 batteries. Herein, a Zn-doped Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid-state ceramic electrolyte stabilized in CO2 was designed and prepared. The additive Zn2+ ions make the crystal structure of the electrolyte denser with strong mechanical properties, providing an optimized network channel for Li+ ions transmission and further improving its ionic conductivity at room temperature. The optimized Zn-doped LATP exhibited an ionic conductivity of 2.45 × 10-3 S cm−1, much higher than that of LATP (2.67 × 10-4 S cm−1). The assembled Li–CO2 battery provides a high discharge capacity of 16,585 mAh/g and more than 180 stable cycles with charge/discharge overpotential less than 1.4 V. Due to the Zn-doped structure, the reduction effect of Ti4+ ions in LATP contact with Li was proved to be effectively suppressed. This doping strategy provides a feasible method for achieving high-performance solid-state Li–CO2 batteries.