Sang Xiaoyu, Hu Kangjia, Chen Jiaxin, Wang Zhangci, Xu Henghui, Huang Yunhui, Hu Xianluo
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China (X. L. Hu.
Angew Chem Int Ed Engl. 2025 Apr 17;64(17):e202500367. doi: 10.1002/anie.202500367. Epub 2025 Feb 25.
Cost-effective micro-sized silicon (μSi) anodes with high specific capacity are promising for high-energy-density lithium-ion batteries but face significant volume changes during cycling. Constructing anion-derived, inorganic-rich solid-electrolyte interphase by electrolyte engineering is considered a viable strategy for stabilizing μSi anodes. However, at low temperatures, temperature-dependent anion-dominated solvation and sluggish Li desolvation hinder cyclability and capacity retention. Here we introduce a unique temperature-inert weakly solvating electrolyte (TIWSE) that preserves the anion-dominated solvation sheath and has weak solvent coordination capability, enabling stable cycling of μSi anodes in subzero environments. The crucial role of NO anions with a high donor number in regulating competitive coordination in TIWSE is unveiled. As a result, μSi||LiNiCoMnO full cells with TIWSE demonstrate impressive capacity retention of 91.8 % at -20 °C and 80.8 % at 30 °C after 100 cycles, along with a high specific capacity of 137.4 mAh g at 6 C. Furthermore, a 1-Ah pouch cell of Si-C||LiNiCoMnO shows remarkable cycling stability with 89.3 % capacity retention over 300 cycles at 30 °C and 77.3 % retention at -20 °C, demonstrating the practical applicability. This work highlights the importance of solvation chemistry in addressing low-temperature challenges and offers new insights into high-energy μSi-based lithium-ion batteries operating under harsh conditions.
具有高比容量且成本效益高的微型硅（μSi）负极，对于高能量密度锂离子电池很有前景，但在循环过程中会面临显著的体积变化。通过电解质工程构建阴离子衍生、富含无机成分的固体电解质界面，被认为是稳定μSi负极的可行策略。然而，在低温下，温度依赖性的阴离子主导溶剂化和缓慢的锂去溶剂化过程会阻碍循环性能和容量保持率。在此，我们引入了一种独特的温度惰性弱溶剂化电解质（TIWSE），它能保持阴离子主导的溶剂化鞘层，且具有较弱的溶剂配位能力，从而使μSi负极在零下环境中能够稳定循环。揭示了具有高给体数的NO阴离子在调节TIWSE中竞争配位方面的关键作用。结果，采用TIWSE的μSi||LiNiCoMnO全电池在100次循环后，在-20°C时容量保持率达91.8%，在30°C时达80.8%，同时在6C倍率下具有137.4 mAh g的高比容量。此外，一个1 Ah的Si-C||LiNiCoMnO软包电池在30°C下300次循环中容量保持率达89.3%，在-20°C下为77.3%，显示出实际应用价值。这项工作突出了溶剂化化学在应对低温挑战方面的重要性，并为在苛刻条件下运行的高能μSi基锂离子电池提供了新的见解。
