Homogeneous In‐Plane Lattice Strain Enabling d‐Band Center Modulation and Efficient d–π Interaction for an Ag2Mo2O7 Cathode Catalyst With Ultralong Cycle Life in Li‐O2 Batteries

Abstract

AbstractAlthough lithium–oxygen batteries (LOBs) hold great promise as future energy storage systems, they are impeded by insulated discharge product Li2O2 and sluggish oxygen reduction reaction/oxygen evolution revolution (ORR/OER) kinetics. The application of a highly efficient cathode catalyst determines the LOBs performance. The d‐band modulation and catalytic kinetics promotion are important concept guidelines for the performance enhancement of cathode catalysts. In this work, the homogeneous in‐plane distortion‐derived synergistic catalytic capability of an Ag2Mo2O7 catalyst with modulated d‐band centers and promoted ORR/OER kinetics is demontrated. The uniform elongation of Ag─O bonds and compression of Mo─O bonds in (020) plane leads to d‐band splitting and d‐band center optimization and delivers improved adsorption behavior for high ORR/OER capability. Furthermore, the spatial and energy overlap of Ag dxz and O2 anti‐bonding π* orbitals facilitate electron injection during ORR process and reduce the energy barrier for charge transfer and O2 desorption during OER process, accelerating the ORR/OER kinetics. As a result, the (020) plane‐exposed Ag2Mo2O7 cathode exhibits ultralong cycle stability of 817 cycles at 500 mA g−1 and large specific discharge/charge capacities of 15898/15180 mAh g−1. This work provides facile concept guidance for optimizing catalytic capability through controlled lattice distortion in cathode catalysts for LOBs.