Regulating the nucleation of Li2CO3 and C by anchoring Li-containing carbonaceous species towards high performance Li-CO2 batteries

Abstract

Li-CO2 batteries provide an attractive and potential strategy for CO2 utilization as well as energy conversion and storage with high specific energy densities. However, the poor reversibility caused by the decomposition obstacles of Li2CO3 and C products is still a challenge for Li-CO2 batteries, which seriously influences its electrochemical performances. Herein, a free-standing MnOOH arrays cathode has been prepared and employed in Li-CO2 battery, which realizes a great improvement of electrochemical performances by adjusting the discharge products distribution. Experiments coupled with theoretical calculations verifies that the formation of Li-containing carbonaceous species (LiCO2, LiCO and Li2CO3) bonded with MnOOH through Li ion regulates the nucleation behavior of Li2CO3 and C, making them grown on MnOOH uniformly. The fine Li2CO3 grains (with a size about 5 nm) embedded into carbon matrix greatly enlarges the contact interface between them, facilitating the transmission of electrons through the discharge products and finally improves CO2 evolution activity. This ingenious design strategy of regulating discharge products distribution to improve electrochemical performances provides a promising way to develop advanced Li-CO2 batteries.