The influence of current density dependent Li2CO3 properties on the discharge and charge reactions of Li-CO2/O2 battery

As a promising energy storage technology, Li-CO 2 /O 2 batteries not only deliver ultrahigh discharge capacity but also capture and convert CO 2 into renewable energy. The exploration into the deposition and decomposition kinetics of discharge product (Li 2 CO 3 ) is urgent for the high thermodynamic stability. Herein, the influence of current density on the essential characteristics of Li 2 CO 3 has been explored. The results show that the Li 2 CO 3 with poor crystallinity and elliptical disk morphology can be obtained at medium current density, corresponding to the excellent electrochemical performance including ultrahigh capacity of 5800 mA h/g, lower discharge-charge gap of 1.15 V, and long-term cycle life of 80 cycles. In addition, the morphology and crystallinity of Li 2 CO 3 are tailored by the relative energy barriers for electron migration and O 2 - generation. At a medium current density (500 mA/g), the accelerated electron migration can realize the nucleation rate equivalent to growth one of Li 2 CO 3 . At this time, Li 2 CO 3 will uniformly deposit on the cathode surface, forming elliptical disk morphology with poor crystallinity. Obviously, this work provides new sights for promoting the development of Li-CO 2 /O 2 battery through rational design of catalysts to accelerate the deposition and decomposition processes of Li 2 CO 3 .