A high-entropy cathode catalyst with multiphase catalytic capability of Li2O2 and Li2CO3 enabling ultralong cycle life in Li–air batteries†

Abstract

For Li–air batteries (LABs), the performance enhancement is significantly restricted by the lack of highly efficient cathode catalysts. It is difficult to achieve multiphase catalysis to facilitate the complicated discharge products, such as Li₂O₂ and Li₂CO₃, in ambient air. Herein, a broad d-band strategy is proposed as the design guidance to fabricate the cathode catalyst with multiphase catalytic capability for LABs. It is demonstrated that the HESe (FeCoNiMnZn)Se₂ exhibits a modulated broad d-band distribution for highly efficient catalyst–adsorbate interaction. Furthermore, the broad d-band distribution leads to the orbital overlaps of metal 3d and O 2p of O₂, CO₂, LiO₂, Li₂O₂ and Li₂CO₃, which can facilitate the electron injection during the discharge process and reduce the energy barrier for charge transfer and the desorption of gas species (O₂ and CO₂) during the charge process. As a result, the HESe cathode delivers an ultralong cycle life over 480 cycles in ambient air without any protection in LABs, and 1050 cycles in Li–CO₂ batteries, demonstrating the highly efficient multiphase catalytic capability for Li₂O₂ and Li₂CO₃.