Adsorption and Diffusion of Potassium on 2D SnC Sheets for Potential High-Performance Anodic Applications of Potassium-Ion Batteries

Abstract

Pertinent electrochemical characteristics based on K-ion batteries (KIBs) represent a compelling class of electrode materials that may substitute lithium-ion batteries, owing to their low cost and common abundance. In this paper, the structural, electronic, and electrochemical features of two-dimensional (2D) material, the so-called SnC monolayer, is investigated for anode applications employing first-principle calculations. Pristine monolayer SnC is found to be an indirect band semiconductor with a band gap of 0.91 and 1.73 eV using PBE and HSE06 schemes, respectively. However, holding a small content of K on the T-site, this 2D material has a semi-metallic behavior (due to the defect state), while the conductivity is enhanced by undertaking the adsorption of K on the H-site. As an anode material, monolayer SnC illustrates a low average open-circuit voltage of 0.415 V for KIBs with a high K storage capacity of 410 mAhg−1. The low diffusion barrier (0.17 eV) on the surface of SnC sheet conducts fast charge/discharge cycles. Our results indicate that the 2D SnC could be a promising anode material for K-ion batteries. According to these findings, we recommend that monolayer SnC can serve as expedient material with tunable capacity and high rate performance for next generation K-ion batteries.