锂离子电池硅基负极电解液添加剂研究进展:挑战与展望

Research progress in the electrolyte additives in silicon-based anode for lithium-ion batteries:Challenges and prospects

随着新能源和动力系统应用的日益成熟,锂离子电池在未来必将发挥越来越重要的作用,高比能电池已经成为当前研究的热点,并不断提出更高的性能要求。具有超高理论能量密度的硅材料被认为是缓解电动汽车行业里程焦虑的新一代负极材料,预示着未来几年将是硅基负极锂离子电池产业化应用的黄金时期。然而,硅在脱/嵌锂过程中会反复收缩膨胀(体积变化率约为300%),致使负极材料粉化、脱落,进而失去电接触,造成负极材料的失活;其次,循环过程中不断的体积变化会对其表面固体电解质界面层造成持续不断的破坏,因此难以形成稳定的固体电解质中间相(SEI)膜,这导致大量活性锂和电解液的消耗,最终导致容量快速衰减。本综述旨在从电解液添加剂在SEI形成和修饰、Lewis碱中和、溶剂化调控等作用机理角度对硅基负极界面恶化方面所面临的挑战进行分析,并重点介绍硅基负极电解液添加剂的最新成果。此外,通过对氟、硅烷、酰胺、氰酸酯等官能团构效关系方面的深入讨论和比较,本综述还深入研究了电解液添加剂的设计问题,以激发读者的新思路和新想法,协助读者识别或者设计合成适用于硅基负极的电解液添加剂,为高比能电池的发展铺平道路。

As the application of new energy and power systems becomes increasingly mature,lithium-ion batteries(LIBs)could play an increasingly crucial role in the future.High-specificenergy batteries could become a research hotspot,constantly introducing greater performance requirements.Silicon-based materials with ultra-high theoretical energy density are the new generation of anode materials that can alleviate the anxiety in the electric vehicle industry.The next few years are anticipated as the golden period for the industrial application and commercialization of silicon-based anode LIBs.However,silicon undergoes repeated shrinkage and expansion during the lithium removal/insertion process(with a volume change rate of approximately 300%),causing the anode material to powder,fall off,and subsequently lose the electrical contact and material deactivation.Moreover,the continuous volume change during the cycle causes damage to the solid electrolyte interphase(SEI)on their surface,making it difficult to form a stable SEI,which leads to the consumption of enormous active lithium and electrolyte and ultimately results in rapid capacity decay.This review aims to analyze the challenges faced by electrolyte additives in SEI formation and modification,Lewis base neutralization,solvation regulation,and other mechanisms of action and highlight the latest achievements of siliconbased electrolyte additives.In addition,through an in-depth discussion and comparison of functional group structures,such as fluorine,silane,amide,cyanate ester,etc.,this review delves into the design of electrolyte additives to inspire the readers to generate new ideas and help them in identifying/designing and synthesizing electrolyte additives suitable for silicon-based anode,thereby paving the way for the development of high-specific-energy batteries.