Germagraphene as promising anode material for Lithium-ion batteries predicted from first-principles calculations

TL;DR

This study predicts that Germagraphene, a germanium-doped graphene, exhibits high capacity, good conductivity, and fast lithium diffusion, making it a promising anode material for lithium-ion batteries based on first-principles calculations.

Contribution

The paper introduces Germagraphene as a novel high-capacity anode material for LIBs, supported by first-principles predictions of its electrochemical properties.

Findings

Specific capacity up to 1734 mAh/g

Low diffusion barrier (~0.151 eV)

Minimal lattice change (~0.48%) during lithiation

Abstract

Finding electrode materials with high capacity is a key challenge for developing Lithium-ion batteries (LIBs). Graphene was once expected to be a promising candidate, but it turns out to be too inert to interact with Li. Here, by using the first-principles calculations, we predict that Germanium doped graphene, termed as Germagraphene which has been achieved in recent experiment, is a promising LIB anode material. We find that at the optimal Ge concentration, which corresponds to the chemical formula C17Ge, the specific capacity for Germagraphene can be as high as 1734 mAh/g, over four times larger than graphite. We show that the material is conductive before and after Li adsorption. We also investigate the diffusion process of Li on Germagraphene, and find that the diffusion barrier is low (~0.151 eV), implying fast Li diffusion. The calculated average intercalation potential is very low (~0.03 V), which is beneficial for increasing the working voltage for the full-cells. In addition, during the process of Li intercalation, the lattice change for the material is quite small (~0.48%), implying good cycle performance. These results suggest that Germagraphene could be a promising high-capacity anode material for LIBs.