Two-dimensional honeycomb borophene oxide: A promising anode material offering super high capacity for Li/Na-ion batteries

TL;DR

This study uses first-principles calculations to show that honeycomb borophene oxide is an almost ideal 2D anode material with extremely high capacity for Li/Na-ion batteries, outperforming existing materials.

Contribution

It introduces honeycomb borophene oxide as a novel 2D anode material with record-high storage capacities for Li and Na ions, based on theoretical calculations.

Findings

High theoretical capacity: 2137 mAh/g for Li, 1425 mAh/g for Na

Excellent conductivity and fast ion diffusion with barriers below 0.5 eV

Minimal lattice change (<6.2%) during ion intercalation

Abstract

Rational design of novel two-dimensional (2D) electrode materials with high capacity is crucial for the further development of Li-ion and Na-ion batteries. Herein, based on first-principles calculations, we systemically investigate Li and Na storage behaviors in the recently discovered 2D topological nodal-loop metal - the honeycomb borophene oxide (h-B2O). We show that h-B2O is an almost ideal anode material. It has good conductivity before and after Li/Na adsorption, fast ion diffusion with diffusion barrier less than 0.5 eV, low open-circuit voltage (less than 1 V), and small lattice change (less than 6.2%) during intercalation. Most remarkably, its theoretical storage capacity is extremely high, reaching up to 2137 mAh/g for Li and 1425 mAh/g for Na. Its Li storage capacity is more than six times higher than graphite (372 mAh/g), and is actually the highest among all 2D materials discovered to date. Our results strongly suggest that 2D h-B2O is an exceedingly promising anode material for both Li- and Na-ion batteries with super high capacity.