Unveiling a new type of boron-doped carbon sheets as an anode for Calcium-ion batteries

Abstract

Calcium-ion batteries (CIBs) are gaining attention as a viable substitute for lithium-ion batteries (LIBs) because of their enhanced safety characteristics and economical nature. This study employed density functional theory computations to examine suitability of boron-doped carbon sheets (BC_x, where x equals 2) as a desirable anode material for CIBs. BC_x material possesses a significantly porous configuration and exhibits a stronger propensity for Ca-ions to bond to its vacant sites. Parameters such as diffusion energy barrier (DEB), theoretical specific capacity (TSC), open-circuit voltage (OCV), and partial density of states have been computed and subsequently analyzed and discussed. Furthermore, the developed anode material exhibited complete saturation with seven Ca-ions distributed across various active sites. This observation suggests a substantial TSC of 1359 mAh g⁻¹ along with a minimal OCV of 0.39 V. Inclusion of a B₂C₄ ring, which exhibited a DEB of 0.15 eV, significantly enhanced mobility of Ca-ions. Consequently, BC_x emerges as a viable candidate for anode material in CIBs, offering advantages such as prolonged cycle life, rapid charge–discharge rates, and its favorable attributes of low OCV and DEB. Additionally, its theoretical specific capacity value remains high, further contributing to its suitability for CIB applications.