Revealing the potential of a C6BN/black phosphorene nanocomposite as an anode material for sodium-ion batteries by atomistic simulation: DFT and AIMD

Abstract

Black phosphorus (BP) has recently been regarded as a promising anode for sodium-ion batteries (SIBs) owing to its high storage capacity, rapid Na mobility in its lamellar structure, and low redox potential. However, its poor cyclability due to structural instability hampers its further implementation in SIBs. Here, we propose to design a novel two-dimensional nanocomposite by vertically stacking a C6BN sheet on a black phosphorene layer (C6BN/Black-Pn). Atomistic simulations by the van der Waals corrected density functional theory method were conducted to assess the suitability of the designed C6BN/Black-Pn model as a potential anode in SIBs. Benefiting from C6BN's electronic and chemical features, Black-Pn's band gap in C6BN/Black-Pn is diminished to 0.14 eV, which disappears and indicates metallic character upon sodiation. Additionally, the optimized Na adsorption energy within the nanocomposite is decreased to −2.06 eV, compared to −1.76 eV in pure Black-Pn and −0.98 eV in C6BN, with a modest diffusion barrier of 0.23 eV. A maximal theoretical capacity of 568.77 mAh/g and a low potential of 0.48 V are predicted for the nanocomposite. The above evaluation of C6BN/Black-Pn electrode for SIBs may provide better insights into adopting a physical approach to address BP electrochemical failures for advanced energy storage.