Eutectogel Electrolyte Constructs Robust Interfaces for High‐Voltage Safe Lithium Metal Battery

• Published in: Advanced science Vol. 11; no. 23; pp. e2310136 - n/a
• Main Authors: Wu, Wanbao, Li, Deping, Gao, Chaochao, Wu, Hao, Bo, Yiyang, Zhang, Jichuan, Ci, Lijie, Zhang, Jiaheng
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01-06-2024; John Wiley and Sons Inc; Wiley
• Subjects: Electrolytes; eutectogel electrolyte; high voltage; Interfaces; LCO cathode; Lithium; lithium metal batteries; Membranes; Morphology; Polymers; Scanning electron microscopy; Spectrum analysis; structure/interface stability; Transmission electron microscopy; eutectogel electrolyte; high voltage; LCO cathode; structure/interface stability; lithium metal batteries
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202310136

Dramatic growth of lithium dendrite, structural deterioration of LiCoO2 (LCO) cathode at high voltages, and unstable electrode/electrolyte interfaces pose significant obstacles to the practical application of high‐energy‐density LCO||Li batteries. In this work, a novel eutectogel electrolyte is developed by confining the nonflammable eutectic electrolyte in a polymer matrix. The eutectogel electrolyte can construct a robust solid electrolyte interphase (SEI) with inorganic‐rich LiF and Li3N, contributing to a uniform Li deposition. Besides, the severe interface side reactions between LCO cathode and electrolyte can be retarded with an in situ formed protective layer. Correspondingly, Li||Li symmetrical cells achieve highly reversible Li plating/stripping over 1000 h. The LCO||Li full cell can maintain 72.5% capacity after 1500 cycles with a decay rate of only 0.018% per cycle at a high charging voltage of 4.45 V. Moreover, the well‐designed eutectogel electrolyte can even enable the stable operation of LCO at an extremely high cutoff voltage of 4.6 V. This work introduces a promising avenue for the advancement of eutectogel electrolytes, the nonflammable nature and well‐regulated interphase significantly push forward the future application of lithium metal batteries and high‐voltage utilization of LCO cathode.
A well‐designed eutectogel electrolyte constructs a robust solid electrolyte interphase with inorganic‐rich LiF and Li3N, contributing to a uniform Li deposition. The severe interface side reactions between LiCoO2 cathode and electrolyte can be retarded with an in situ formed protective layer. The well‐regulated interphases ensure the long cycling performance of high energy density LCO||Li cells at high voltage.