Computational verification of conductive Be2Zn monolayer as a superior anode for alkali and alkaline ion batteries

Abstract

Availability of high-performance anode materials remains a great challenge for the clean energy storage systems. Here, we predict the planar hexacoordinate Be2Zn monolayer by first-principles calculations as a highly conductive metallic conductor with all-round structural stabilities. More impressively, the material delivers ultrahigh theoretical specific capacities of 1285, 1928, 1285, and 3856 mA h g−1 for Li, Na, K, and Ca atoms, respectively, with low migration barriers of 18, 7, 4, and 119 meV as well as with favorite average open-circuit voltages of 0.346, 0.366, 0.322, and 0.151 V. Its structural reversibility at the maximum loading concentrations is jointly confirmed by ab-initio molecular dynamics simulations at the upper temperature of 400 K for commercial battery operation under normal ambient environments and subsequent energy minimization calculations. Moreover, the monolayer can tolerate heavy tensile strain up to around 20% far surpassing the structural deformations at different charging stages, which convincingly guarantees its superlative cycle stability during the charging and discharging processes. Taken together, these appealing findings show that the metallic Be2Zn monolayer has great potential to be used as a universal Li, Na, K, and Ca ion battery anode.