Theoretical Studies on Sodium Storage Mechanism in Hard Carbon Anodes of Sodium-Ion Batteries: Molecular Simulations Based on Machine Learning Force Fields

TL;DR

This study uses advanced machine learning-based molecular simulations to explore and clarify the complex sodium storage mechanisms in hard carbon anodes of sodium-ion batteries, providing insights for improved battery design.

Contribution

It introduces a novel combination of machine learning force fields with multiscale simulations to systematically investigate sodium storage in hard carbon, advancing theoretical understanding.

Findings

Revealed detailed sodium adsorption and intercalation behaviors.

Identified distribution patterns of sodium ions in hard carbon.

Provided a theoretical basis for optimizing sodium-ion battery performance.

Abstract

Sodium-ion batteries (SIBs) have garnered significant attention in recent years as a promising alternative to lithium-ion batteries (LIBs) due to their low cost, abundant sodium resources, and excellent cycling performance. Hard carbon materials, characterized by their high specific capacity, outstanding cycling stability, and low cost, have emerged as potential candidates for SIB anodes. However, the sodium storage mechanism in hard carbon anodes remains highly complex, especially in disordered structures, and is yet to be fully understood. To address this, we employed relative machine learning force fields (MLFFs) in conjunction with multiscale simulation techniques to systematically investigate the sodium storage behavior in hard carbon. By integrating simulations, this study provides a detailed exploration of sodium adsorption, intercalation, and filling mechanisms. High-precision, large-scale simulations reveal the dynamic behavior and distribution patterns of sodium ions in hard carbon. The findings not only deepen our understanding of sodium storage mechanisms in hard carbon anodes, but also offer a theoretical foundation for optimizing future SIB designs, while introducing novel simulation methodologies and technical frameworks to enhance battery performance.