Sulfone electrolyte based quasi-solid-state high-voltage lithium metal batteries enabled by component design and interfacial engineering

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2025-01, Vol.504, p.158719, Article 158719
• Main Authors: Zhou, Qingru, Huang, Zhouyu, Yang, Tianqi, Zhang, Haiyuan, Yao, Xiayin, Zhang, Wenkui, Huang, Hui, Xia, Yang, Tao, Xinyong, Zhang, Jun
• Format: Article
• Language: English
• Subjects: High-voltage LiCoO2; In situ polymerization; Lithium metal batteries; solid electrolyte interface (SEI); Sulfone-based electrolytes
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.158719

[Display omitted] •A sulfone-base quasi solid electrolyte (MSFE) is designed for lithium batteries.•The MSFE showed wide voltage, high ionic conductivity, and flame-retardant.•The MSFE enabled high voltage batteries with LiCoO2 cathode and Li anode.•A hybrid electrode/electrolyte interface of LiF, Li3N , LiBxOy and LiSixOy was revealed. Sulfone-based electrolyte (SL) as a novel type electrolyte for lithium-ion batteries (LIBs) has attracted increasing attention due to its exceptional high-voltage stability and flame retardancy. However, the polar thionyl groups in sulfone lead to continuous reaction with lithium (Li) metal, and high viscosity of sulfone could decrease its Li+ ionic conductivity, which obstructs further application of SL in Li metal batteries (LMBs). Herein, the methylenebisacrylamide (MBA) crosslinked SL, fluorinated ethylene carbonate (FEC) based quasi-solid-state electrolyte (MSFE) was designed to address above problems. By introducing FEC to passivate metallic Li and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (OTE) as diluent to decrease viscosity of electrolyte, MSFE exhibits a high ionic conductivity of 1.77 × 10−3 S cm−1 and wide electrochemical stability window up to 5.6 V. Therefore, LiCoO2/MSFE/Li (LCO/MSFE/Li) batteries show a high capacity retention of 95.7 % after 100 cycles under 0.2C. Moreover, formation mechanism and kinetic evolution of the hybrid EEI is revealed via density functional theory (DFT) calculations and in-situ galvanostatic electrochemical impendence spectra (IS-GEIS) coupled with distribution relax time (DRT) technology. Well-formed hybrid EEI prevents the structural degradation of LCO materials and induces uniform deposition of Li-ion to inhibit formation of Li dendrites. This work provides a new insight towards high energy density in-situ polymerized solid LMBs.