Perfluoropolyether-based block copolymer electrolytes enabling high-temperature-resistant solid-state lithium metal batteries

• Published in: Journal of power sources Vol. 561; p. 232751
• Main Authors: Sun, Yuxue, Zhang, Xiaorong, Xu, Pingbo, Liu, Ying, Dong, Feilong, Ma, Chunhui, Liu, Jun, Xie, Haiming
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.03.2023
• Subjects: All-solid-state lithium metal battery; Block copolymer electrolyte; High temperature; Perfluoropolyether; Thermal stability; Perfluoropolyether; All-solid-state lithium metal battery; High temperature; Block copolymer electrolyte; Thermal stability
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2023.232751

In recent years, the safety problems caused by thermal runaway during the operation of lithium-ion batteries (LIBs) are common. Therefore, fabrication of LIBs that can be used under high temperature is the current research focus. In this work, we designed a perfluoropolyether (PFPE)-based block copolymer electrolyte (PFPEBCPE). The PFPE blocks can improve the thermal stability of PFPEBCPE. The LiFePO4//Li cell assembled with PFPEBCPE exhibits excellent capacity retention (100 cycles, 90%), long-term charge-discharge stability (Coulomb efficiency, 99%) and rate performance (1 C, 137.7 mA h g−1) at 120 °C. The PFPE blocks can also improve the electrochemical stability window (5.0 V) and the lithium-ion transference number (0.56) of PFPEBCPE. In addition, PFPEBCPE can participate in the creation of stable fluorinated solid electrolyte interphase (SEI), enabling the Li//Li symmetric cell to cycle stably for up to 1500 h at a current density of 0.1 mA cm−2. •The PFPE block allows the decomposition temperature of PFPEBCP up to 345 °C.•The PFPE block can adsorb TFSI− and increase the lithium-ion transference number.•The PFPE block can improve the electrochemical stability window of PFPEBCPE.•The LiFePO4//Li cells have excellent cycle and rate performance at 70 and 120 °C.