Computational Screening of Current Collectors for Enabling Anode-free Lithium Metal Batteries

TL;DR

This paper computationally screens and identifies promising current collector materials, particularly Li-alloys, to improve lithium nucleation and growth in anode-free lithium metal batteries, enhancing energy density and cycling stability.

Contribution

It introduces a density functional theory-based screening method to identify Li-alloys as superior current collectors for anode-free lithium batteries, improving performance.

Findings

Li-alloys have ideal lithium adsorption and diffusion properties.

Li-alloys can significantly enhance specific energy.

Current metal collectors are less effective for uniform lithium growth.

Abstract

Lithium metal cells are key towards achieving high specific energy and energy density for electrification of transportation and aviation. Anode-free cells are the limiting case of lithium metal cells involving no excess lithium and the highest possible specific energy. In addition, anode-free cells are easier, cheaper and safer as they avoid handling and manufacturing of lithium metal foils. Issues related to dendrite growth and poor cycling are magnified in anode-free cells due to lack of excess lithium. Electrolyte and current collector surface play a crucial role in affecting the cycling performance of anode-free cells. In this work, we have computationally screened for candidate current collectors that can nucleate lithium effectively and allow uniform growth. These are determined by the free energy of lithium adsorption and lithium surface diffusion barrier on candidate current collectors. Using density functional theory calculations, we show that Li-alloys possess ideal characteristics for Li nucleation and growth. These can lead to vastly improved specific energy compared to current transition metal current collectors.