Insights into stability, kinetic, and electrochemical performance of silicon-doped boron carbon nitride as a promising anode material for lithium-ion battery : First-principles calculations

Two-dimensional boron carbon nitride (BCN) has gained increasing attention for use in lithium-ion batteries (LIBs) due to its unique electronic properties. In this study, the effects of silicon (Si)-doping on the structural, kinetic, and electrochemical properties of BCN are investigated by density functional theory calculations. Minor Si-doping in the BCN lattice (Si-BCN) is found to alter the pore radius, which enhances Li-ion adsorption and diffusion. The Li-ion adsorption energy (Ead) increases from −2.02 eV in pristine BCN to −2.75 eV in Si-BCN nanosheet, indicating stronger Li-ions interaction. This more negative Ead enhances the stability of Li storage sites, while the reduced diffusion barrier (0.13 eV) facilitates efficient Li-ion transport in Si-BCN. Moreover, Si-doping leads to a reduction in the band gap to 1.12 eV, transitioning the material from semi-metallic to metallic behavior and suggesting improved electronic conductivity. The theoretical capacities are 1456 mAh∙g−1 for pristine BCN and 1428 mAh∙g−1 for Si-BCN. Although the capacities are comparable, the increased electronic and ionic conductivities of Si-BCN allow for faster de−/lithiation and show the possibility for faster charging/discharging Li-ion cells.