Enhanced electrochemical performance of a Li-O2 battery using Co and N co-doped biochar cathode prepared in molten salt medium

Abstract

Lithium-oxygen (Li-O2) batteries due to their high energy density are considered a promising alternative to the conventional lithium-ion batteries for electrical vehicles and energy storage. However, the practical application of Li-O2 batteries is significantly impeded by the sluggish electrocatalytic kinetics of oxygen reduction and oxygen evolution reaction that occur on the air-cathode electrode during the discharge and charge processes. Herein, a three-dimensional Co and N co-doped biochar derived from wood in the molten salt medium was developed as cathode for Li-O2 batteries. A three-dimensional self-supporting electrode co-doped with Co and N is obtained, which can be directly used as the positive electrode of a lithium-air battery, exhibiting high specific capacity (under the condition of current density of 0.05 mA cm−2, the discharge specific capacity is 9.44 mAh cm−2) and excellent cycle stability (under the limited capacity of 0.5 mAh cm−2, it can be cycled 113 times).