Unique hierarchically structured medium-entropy nitride for rechargeable Li–CO2 batteries with high capacity

The research on Li–CO₂ batteries with substantial energy density is notable for its potential contribution to the carbon neutrality. A pivotal aspect of the study is the advancement of cost-effective and efficient cathode catalysts to improve Li–CO₂ battery performance. Herein, a unique hierarchical medium-entropy nitride (CoNiMnN@C) composite is prepared through the utilization of mixed metal solution construction of metal organic frameworks, aiming at developing cathode catalysts with superior dispersion ability of lithium carbonate and conductivity. As a result, the CoNiMnN@C based Li–CO₂ battery presents an exceptional discharge capacity of 23555 mA h g⁻¹ due to the distinctive medium-entropy effect of CoNiMnN and the hierarchical structure that exposes numerous catalytic active sites. The battery also exhibits impressive durability across multiple cycles lasts 500 h and maintains a low overpotential of 1.48 V at a discharge/charge rate of 100 mA g⁻¹. This work extends the application of medium-entropy materials in Li–CO₂ batteries and provides unique ways to its design.