Exploring the potential of di-boron di-nitride monolayer (o-B2N2) as a K-ion battery anode: A DFT study

Due to favorable future use of electrochemical energy storage systems in portable electronic devices, these systems have received much attention. Employing these systems in "smart" clothes equipped with piezoelectric pieces to gain energy from body movement and roll-up displays is promising. Nevertheless, further development of these technologies is a significant challenge due to lack of appropriate battery electrodes that supply desirable electrochemical performance. 2D flexible and light materials with remarkable chemical and physical attributes such as acceptable conductivity, high surface metal diffusivity, hydrophilic surfaces, and mechanical strengths were introduced as potential options for battery electrodes. In present research, 2D orthorhombic di-boron di-nitride monolayer (o-B2N2) as a novel 2D boron nitride allotrope has been investigated. Systematically, various impacting factors like their electrochemical and electronic features (theoretical capacity, equilibrium voltage, binding strength, etc.) were investigated. It is noteworthy that specific capacity of K-ion batteries (KIBs) reaches 2347 mAh.g-1. In addition, the existence of o-B2N2 ring accelerates the diffusion of K-ions, and diffusion barriers are 0.14 eV. Mean open circuit voltage (OCV) and low diffusion barrier of o-B2N2 monolayer guarantee long service life and fast charging/discharging for practical purposes. Based on results, monolayer o-B2N2 is proper as a high-performance negative electrode material in KIBs.