Issue 38, 2024

Mitigating the volume expansion and enhancing the cycling stability of ferrous fluorosilicate-modified silicon-based composite anodes for lithium-ion batteries

Abstract

Silicon has emerged as a prominent candidate for anodes in advanced lithium-ion batteries due to its exceptional theoretical capacity and low operational potential. Despite its advantages, silicon-based anodes face significant challenges, including substantial volume changes, formation of an unstable solid-electrolyte interphase (SEI) film, and voltage hysteresis during lithium alloying/dealloying, which compromise their cycling stability. This study introduces a novel ferrous fluorosilicate (FeSiF6)-modified silicon-based composite anode. FeSiF6 is prepared via a simple reaction between Fe–Si alloys and hydrofluoric acid (HF). Various treatment methods are employed to create modified silicon-based composites with different compositions and morphologies. This innovative composite material prevents the formation of crystalline Li15Si4 and facilitates the formation of a stable SEI film, thereby markedly improving the cycling stability of the silicon-based anodes. Among these, the composite material Fe–Si@F@C (consisting of Fe–Si alloy@FeSiF6@graphite) demonstrates a stable discharge capacity of 975 mA h g−1 after 200 cycles at 1 A g−1, with ∼94% capacity retention, and outstanding rate performance (664.4 mA h g−1 at 4 A g−1). In comparison, the Fe–Si alloy/graphite anode without FeSiF6 shows a much lower discharge capacity of 458 mA h g−1 at 1 A g−1 after 200 cycles and 291.8 mA h g−1 at 4 A g−1. These findings underscore the critical role of FeSiF6 in modifying silicon-based anodes and enhancing their cycling stability, significantly increasing their potential for commercial application in next-generation lithium-ion batteries.

Graphical abstract: Mitigating the volume expansion and enhancing the cycling stability of ferrous fluorosilicate-modified silicon-based composite anodes for lithium-ion batteries

Supplementary files

Article information

Article type
Paper
Submitted
12 4 2024
Accepted
29 8 2024
First published
30 8 2024

J. Mater. Chem. A, 2024,12, 25747-25760

Mitigating the volume expansion and enhancing the cycling stability of ferrous fluorosilicate-modified silicon-based composite anodes for lithium-ion batteries

J. Sun, X. Liu, P. Zheng, Y. Zhao, Y. Zheng, J. Chai and Z. Liu, J. Mater. Chem. A, 2024, 12, 25747 DOI: 10.1039/D4TA02532F

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