Highly Efficient Cu‐Porphyrin‐Based Metal–Organic Framework Nanosheet as Cathode for High‐Rate Li‐CO2 Battery

Abstract The lithium‐carbon dioxide (Li‐CO 2 ) battery as a novel metal‐air battery has a high specific energy density and unique CO 2 conversion ability. However, its further development is limited by incomplete product decomposition resulting in poor cycling and rate performance. In this work, Cu‐tetra(4‐carboxyphenyl) porphyrin (Cu‐TCPP) nanosheets are prepared through the solvothermal method successfully. An efficient Li‐CO 2 battery with Cu‐TCPP as catalyst achieves a high discharge capacity of 20393 mAh g −1 at 100 mA g −1 , a long‐life cycle of 123 at 500 mA g −1 , and a lower overpotential of 1.8 V at 2000 mA g −1 . Density functional theory calculation reveals that Cu‐TCPP has higher adsorption energy of CO 2 and Li 2 CO 3 compared with TCPP, and a large number of electrons gather near the Cu‐N 4 active sites in Cu‐TCPP. Therefore, the excellent CO 2 capture ability of the porphyrin ligand and the synergic catalytic effect of Cu atom in Cu‐TCPP promote the thermodynamics and kinetics of CO 2 reduction and evolution processes.