Metallic three-dimensional porous siligraphene as a superior anode material for Li/Na/K-ion batteries

Abstract

Due to the high specific capacity and low open circuit voltage (OCV), 2D siligraphene has been widely considered as a promising anode material for metal ion batteries (MIBs). Nonetheless, its electrochemical performance is greatly impeded by low mechanical stiffness, poor hopping dynamics and small pore size. Motivated by the great success of 3D carbon materials, we propose a metallic porous 3D-SiC anode using the corresponding 2D tetragonal SiC as a structural unit. By first principles molecular dynamics, mechanical property and phonon spectrum calculations, it is found that 3D-SiC possesses good thermal, mechanical and dynamical stability. The maximum Young’s and bulk moduli of 3D-SiC are 217.16, 400.90 GPa, respectively, exhibiting a moderate mechanical stiffness. More importantly, the intrinsically high electrical conductivity, unique porous structure and low mass density make the 3D-SiC a promising anode candidate for Li/Na/K-ion batteries with small volume changes (6.43 %, 3.75 % and 8.66 %), low diffusion barriers (0.17, 0.19 and 0.017 eV), high storage capacities (947, 947 and 724 mA h/g) and low average OCVs (0.56, 0.34 and 0.11 V). The encouraging results show that siligraphene-based porous 3D anodes are worthy of further investigation for MIBs.