Engineering durable interphases for high-voltage Li-ion batteries under thermal stress
Shiming Chen, Wenguang Zhao, Guorui Zheng, Chenyu Yang, Taowen Chen, Hengyu Ren, Yue Zuo, Xiangming Yao, Ke Li, Haoyu Xue, Jianjun Fang, Yuxiang Huang, Kai Yang, Zu‐Wei Yin, Luyi Yang, Feng Pan
Abstract
ABSTRACT Achieving stable cycling of high-voltage cathodes at elevated temperatures remains a critical challenge due to intensified interfacial side reactions and the accelerated dissolution of the cathode electrolyte interphase (CEI). In this work, based on theoretical calculations, Li2SO3 with desirable thermal stability and adhesiveness is proposed as a thermally stable binding agent between the selected CEI components (LiF and Li3PO4, where Li3PO4 facilitates fast Li+ transport and thermal stability, while LiF serves as a stable, electron-blocking framework) to prevent undesirable dissolution. This is achieved by leveraging electrolyte engineering to modulate the solvation environment and promote the in-situ formation of the aforementioned CEI architecture. Owing to its structural and compositional stability at elevated temperatures, the constructed CEI effectively mitigates interfacial side reactions even under elevated temperature conditions. As a result, the uncommon achievement of stable cycling for LiCoO2 at 4.6 V and 45°C was realized, demonstrating 81.9% capacity retention over 500 cycles. This work provides a transformative pathway for designing a durable CEI layer tailored to high-voltage and elevated temperature applications, paving the way for lithium-ion batteries to operate reliably in extreme environments.