Nitrogen Doped γ-Graphyne: A Novel Anode for High-Capacity Rechargeable Alkali-Ion Batteries

High energy density is the major demand for next-generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon-based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ-graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g^-1 ) and Na (570.4 mAh g^-1 ) storage capacities at 100 mA g^-1 and presents excellent rate capabilities (526 mAh g^-1 for LIBs and 180.2 mAh g^-1 for SIBs) at 5 A g^-1 . The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (E_b ) and adsorption energies (E_ad ) of Li/Na atoms in NGY are also studied and imine-N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first-principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes.