Adsorption and diffusion of potassium on layered SnO: a DFT analysis

Abstract

Owing to their low cost, potassium-ion batteries (PIBs) are considered the best alternatives to Li-ion batteries (LIBs) due to the high abundance and reactivity of K. However, the large ionic size of K than Li, hinder the commercial availability of PIBs. Herein, DFT calculations are employed to shed light on the electrochemical performance of 2D SnO as an anode for PIBs. The electronic properties of bare SnO reveal semiconducting nature. However, it is metallic with a small amount of K-adsorption. As an anode for PIBs, 2D SnO has a very low average open-circuit voltage (OCV) of 0.292 V with a high K storage capacity (398 mAh g-1). Additionally, the outcomes of the AIMD simulations of the SnO monolayer are displayed with low and high content of K-loading which shows the thermal stability of the host material for PIBs. Eventually, we discuss the potassiation and depotassiation mechanism of the SnO sheet, which reveal fast charging and discharging rates due to the low activation energy barrier (0.07 eV). Based on the above fascinating outcomes, the SnO monolayer could be a promising anode for rechargeable PIBs. Graphical Abstract: The table of content (TOC) depicts the structural model of SnO monolayer as anode material and rapid charging and discharging processes for K-migration.