A novel efficient electrocatalyst for oxygen reduction and oxygen evolution reaction in Li-O2 batteries: Co/CoSe embedded N, Se co-doped carbon

The research of highly efficient and large-capacity energy storage systems is the focus of the research community and the market. Lithium-oxygen (Li-O 2 ) batteries have shown great potential as next generation secondary batteries since their energy density is comparable to that of gasoline. Herein, we report a three dimensional (3D) self-supporting Co-CoSe@NSeC/bioC cathode fabricated through growing cobalt based metal organic framework (ZIF-67) on biomass and subsequent high-temperature selenization. The as synthesized Co-CoSe@NSeC/bioC cathode, benefiting from the 3D porous structure, the active defects derived from the doping of N, Se heteroatoms in carbon skeleton, and the highly-active of Co/CoSe heterojunction, shows excellent oxygen reduction reaction/oxygen evolution reaction (ORR/OER) electrocatalytic activity. It delivers a high specific capacity of 9.1 mAh·cm −2 at a current density of 0.05 mA·cm −2 and maintains 78 stable cycles. The good performance of Co-CoSe@NSeC/bioC proves its potential as cathode for Li-O 2 batteries. • 3D free-standing Co-CoSe@NSeC/bioC cathode was prepared by growing ZIF-67 on biomass and subsequent selenization. • This cathode shows good oxygen reduction and oxygen evolution reaction electrocatalytic activity. • The Li-O 2 batteries with Co-CoSe@NSeC/bioC cathode deliver superior capacity and cycle performance. • 3D porous structured, N, Se co-doping and Co/CoSe heterojunction synergistically enhance the battery performance.