Engineering of MnTe/MnO Heterostructures with Interfacial Electric Field Modulation for Efficient and Durable Li-O Batteries.

Design and synthesis of highly active and robust bifunctional cathode catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are of vital significance for practical applications of lithium-oxygen (Li-O) batteries. Herein, a built-in electric field (BIEF) strategy is reported to fabricate MnTe/MnO heterostructures with a large work function difference (ΔΦ) as a bifunctional cathode catalyst in Li-O batteries. The MnTe/MnO heterostructures with nanosheets and microporous structures result in an abundance of exposed active sites and facilitate mass transfer. More importantly, the heterogeneous MnTe/MnO nano-interface region provides a BIEF that can trigger interfacial charge redistribution, fine-tune the adsorption energy of oxygen intermediates, and alter the morphology of discharge products to accelerate ORR/OER kinetics. Impressively, the fabricated Li-O batteries with MnTe/MnO cathode showcases exhibit excellent electrochemical performances, including low charging overpotential, a high specific capacity of 11930 mA h g, and good cycle stability over 350 cycles even with a fixed specific capacity of 500 mA h g at a current density of 500 mA g. This work provides an avenue for the rational design of high performance heterostructure electrocatalysts toward practical applications for rechargeable Li-O batteries.