Ultra-High Lithium Storage Capacity of Al2C Monolayer under Restricted Multilayered Growth Mechanism

TL;DR

This paper proposes a novel 2D Al2C monolayer anode with a restricted multilayered lithium growth mechanism, achieving ultra-high capacity and fast diffusion for safer, high-energy lithium-ion batteries.

Contribution

It introduces a new restricted multilayered growth mechanism for lithium on 2D materials, demonstrated on Al2C monolayer, with first-principles calculations showing exceptional capacity and diffusion properties.

Findings

Al2C monolayer has a specific capacity of 4059 mAh/g.

The diffusion barrier for lithium is very low, 0.039-0.17 eV.

The open circuit voltage is in a safe, low range of 0.002-0.34 V.

Abstract

Designing anode materials with high lithium specific capacity is crucial to the development of high energy-density lithium ion batteries. Herein, a distinctive lithium growth mechanism, namely, the restricted multilayered growth for lithium, and a strategy for lithium storage are proposed to achieve the balance between the ultra-high specific capacity and the need to avert uncontrolled dendritic growth of lithium. In particular, based on first-principles computation, we show that the Al2C monolayer with planar tetracoordinate carbon structure can be an ideal platform for realizing the restricted multilayered growth mechanism as a 2D anode material. Furthermore, the Al2C monolayer exhibits ultra-high specific capacity of lithium of 4059 mAh/g, yet with a low dif-fusion barrier of 0.039-0.17 eV as well as low open circuit voltage in the range of 0.002-0.34 V. These novel properties endow the Al2C monolayer a promising anode material for future lithium ion batteries. Our study offers a new way to design promising 2D anode materials with high specific capacity, fast lithium-ion diffusion, and safe lithium storage mechanism.