Composite Hybrid Quasi-Solid Electrolyte for High-Energy Lithium Metal Batteries

Exploring quasi-solid electrolytes with superior ionic conductivities, wide electrochemical stability window, desirable compatibility toward lithium metal, and facile processability for high-energy lithium metal batteries remains a challenge. In this work, all of these issues are fully addressed via a composite hybrid design, of which poly(ethylene oxide) (PEO) is used as a polymeric host and guarantees the interfacial compatibility toward lithium metal, highly conductive and thermally stable ionogel aims at suppressing PEO crystallization and enhancing conductivity, and garnet conductor enhances mechanical and electrochemical stabilities. Such a composite hybrid design yields the required quasi-solid electrolyte, which not only shows a high ionic conductivity of 7.4 x 10(-4) S cm(-1) at 25 degrees C but also extends the electrochemical stability window to 5.5 V vs Li/Li+, demonstrated with the interacted and monolithic structure of the composite hybrid quasi-solid electrolyte by XPS. Moreover, the composite hybrid quasi-solid electrolyte suppresses dendrite growth with a current density up to 0.7 mA cm(-2). The quasi-solid Li parallel to LiNi0.5Co0.2Mn0.3O2 and Li parallel to LiFePO4 cells using this composite hybrid quasi-solid electrolyte are demonstrated. This study suggests that engineering integration of ionogel, polymer, and inorganic conductor offers an alternative to explore new electrolytes for lithium metal batteries.

Automated summary

This study addresses the challenges of high-energy lithium metal batteries by developing a composite hybrid design for quasi-solid electrolytes, which combine polymer, ionogel, and inorganic conductor to achieve superior ionic conductivity and electrochemical stability. The composite hybrid design not only enhances the compatibility towards lithium metal, but also extends the electrochemical stability window, demonstrating a promising alternative for new electrolytes in lithium metal batteries.