Cu-doped graphene Cu/N2OG: A high-performance alkaline metal ion battery anode with record-theoretical capacity

Anode materials are paramount in dictating the performance of ion batteries. Therefore, the judicious design of novel anode materials boasting superior capacity is crucial to further enhancing the energy density of ion batteries. This study employs first-principles computational methods to systematically investigate the performance of Cu-doped graphene 2D material (Cu/N(2)OG) as an Li-ion batteries (LIBs), Na-ion batteries (NIBs), or K-ion batteries (KIBs) anode. Simulation results indicate that the structural asymmetry introduced by Cu doping significantly increases the active sites of the material, enhancing its theoretical specific capacity for Li/Na/K. Notably, the sodium storage theoretical capacity of Cu/N(2)OG reaches an impressive 3303.7 mAh/g, surpassing the capacity of all currently employed NIBs anode materials. Furthermore, Cu/N(2)OG also boasts high theoretical capacities, yielding capacities of 1651.8 mAh/g for LIBs and 1263.2 mAh/g for KIBs, respectively. The material retains excellent conductivity both prior to and following the adsorption of Li, Na, and K. Furthermore, Cu/N(2)OG demonstrates a low diffusion barrier and minimal lattice changes (<1 %), suggesting its potential as a highperformance anode for LIBs/NIBs/KIBs.