Pentagonal a -BCP: With ultra-high theoretical storage capacity and low diffusion barrier as an anode for lithium-ion batteries

Abstract

Unique structure of two-dimensional (2D) pentagonal materials makes them potentially valuable for applications in many fields, especially in electrode applications for lithium-ion batteries (LIBs). By means of first-principles calculations, we propose a 2D pentagonal material with an indirect bandgap of 2.551 eV, named a-BCP, exhibiting excellent thermodynamic, kinetic, and mechanical stabilities. Additionally, the structure remains stable with a cohesive energy of −5.827 eV at temperatures up to 1400 K, indicating the great chemical stability of a-BCP. Most importantly, a-BCP acting as the anode of LIBs demonstrates an ultra-high theoretical capacity of 2989.51 mA h g−1, a very low diffusion barrier of 0.13 eV, and small volume changes (−6.5%) in the intercalation/decalcification process, suggesting the potential of high energy density and high charge/discharge rate of LIBs. Furthermore, a-BCP possesses the appropriate reduction and oxidation potentials during water decomposition, making it an ideal material for photocatalytic water splitting.