The CrBr3 monolayer: Two dimension sodium ion battery anode material to characterize state-of-charge by magnetism

Abstract

Ion batteries always use the charge properties of electron to estimate the state-of-charge. In this work, we predict that CrBr3 monolayers can be used as anode materials for sodium ion batteries to characterize state-of-charge of corresponding ion batteries by magnetism. According to the first-principles calculations based on density functional theory, the available maximum Na storage capacity of CrBr3 monolayer can reach 795 mAh/g with the ultra-low open circuit voltage (∼0.02 V). Na ions have good diffusion properties in the CrBr3 monolayer, and the corresponding diffusion barrier is about to be 0.22 eV. There is a magnetic configuration transition in CrBr3 monolayer during charge/discharge, which arises from the change in the occupation of Cr-d orbitals. Our results shed a light to subsequently design and search for anode materials, suggesting that the magnetic properties of electrode materials could provide a new path to monitor the state-of-charge of ion battery.