Planar NiC3 as a reversible anode material with high storage capacity for lithium-ion and sodium-ion batteries

Abstract

The recent discovery of a class of desirable anode materials in metallic two-dimensional (2D) transition-metal (TM) carbides has reignited great interest in the search for high-performance rechargeable lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Using an unbiased structure search combined with first-principles calculations, here we identify an entirely planar NiC₃ monolayer as a highly symmetric anode material that fully utilizes the active adsorption sites in the NiC₄ unit and maintains the original active adsorption sites in the n-biphenyl unit. The outstanding stability of the NiC₃ monolayer is confirmed by its superior cohesive energy, positive phonon modes, high thermal stability and strong mechanical stability. Intriguingly, the current design of entirely planar NiC₃ monolayer demonstrates extraordinary ultrahigh storage capacity, fast charge/discharge capability and low open-circuit voltage. In particular, the capacity for Li and Na storage on the NiC₃ monolayer reaches 1698 mA h g⁻¹, ∼33% higher than the previously reported record (1278 mA h g⁻¹ in puckered TiC₃ monolayer) for 2D materials. The present results have broad implications for other 2D carbides as reversible anode materials for LIBs and SIBs that likely harbor similar novel functional performance.