Open active sites of Co-MOF functionalized Ti3C2 MXene heterostructure with the enhanced performance in Li-O2 battery

Abstract

The sluggish kinetics was determined by the discharge product properties, tri-phase reaction interface and side reaction. Rationally electrocatalyst designing could optimize tri-phase reaction interface, tuning the discharge product and avoid side reaction to facilitate the reaction rates of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in Li-oxygen batteries (LOBs). Herein, the optimized Co-MOF with open active sites was anchored on the high conductivity Ti₃C₂ matrix (Co-MOF/Ti₃C₂) to improve the oxidation resistance. The layer spacing of accordion-like MXene could optimized the growth of Co-MOF, reducing the size of Co-MOF, thus fully exposing the active site. This unique structure enhanced the transfer of charge, the adsorption of intermediates, and the resistance to oxygen attack. Served as the electrocatalyst in LOB, the Co-MOF/Ti₃C₂ presented the lower overpotential of 0.99 V, higher specific capacity of 24028 mAh g⁻¹, as well as long-term durability of 4 times than the Co-MOF. It provided a new strategy for rationally designing of the metal-O₂ battery related electrocatalysts.