A novel highly stable two-dimensional boron phase with promising potentials in energy fields

Abstract

A highly stable new structural phase of monoelemental two-dimensional boron sheet has been discovered. Such new material was acquired by removing the metal atom layers from the quasi-layered boride material AlMgB₁₄, inspired by the top-down synthesis of MXenes, which includes the direct etching and exfoliation of the bulk MAX phase. It has been shown that this structure possesses distinct stability over other two-dimensional boron phases, which is caused by the B–B single bonds that connect B₁₂ clusters and three-coordinate boron atoms, instead of the universally existing three-center two-electron B–B bonds. This new structure has proved to be a direct narrow bandgap semiconductor with intermediate bands and favorable for metal cation and hydrogen molecule adsorption. Specifically, this new structure exhibits particularly high specific capacities as anodes for various metal ion batteries. The findings indicate that this new structure of two-dimensional boron has great potential in the energy fields, such as high-efficiency solar cells, energy storage devices and hydrogen storage substrates.