First-principles study of bismuthene as a high energy density and excellent rate performance anode material for potassium-ion batteries

Abstract Potassium-ion batteries (KIBs), with their abundance of resources, lower cost, high ion conductivity, and comparable redox potential, hold potential as an alternative to lithium-ion batteries (LIBs) for large-scale energy storage. Nonetheless, the scarcity of high-performance electrode materials remains a major obstacle in the advancement of KIBs. Here, the viability of bismuthene as an anode material for KIBs was systematically investigated using first-principles calculations. We found that bismuthene exhibits a maximum adsorption capacity of two layers of K atoms, offering a moderate theoretical capacity of 256.5 mAh g −1 . Additionally, the adsorption of K atoms on bismuthene leads to a notable enhancement in the electronic conductivity. Moreover, the ultralow average open circuit voltage (0.17 V) and diffusion barrier (0.02 eV) of K on bismuthene monolayer along the zigzag direction, suggesting a high energy density and outstanding rate performance of batteries. Hence, bismuthene demonstrates remarkable potential as a high-performance KIBs anode material, making it a hopeful contender in the field of energy storage.