In-situ constructing “ceramer” electrolytes with robust-flexible interfaces enabling long-cycling lithium metal batteries

The lifetime and safety of lithium metal batteries (LMBs) with commercial polyolefin separators and liquid electrolytes are deteriorated by the lithium dendrites, as well as leakage and combustion of liquid electrolytes. To effectively address these issues, a “ceramer” electrolyte is in-situ synthesized to exquisitely combine meritorious properties of both ceramic silica (e.g. high modulus) and polymer poly-1,3-dioxolane (e.g. flexibility/good interface with electrodes), leading to excellent performance for the LMBs. The lithium anodes with the novel “ceramer” electrolyte exhibit ultra-long cycle life and lithium dendrite-free property that is confirmed by in-situ optical microscope. The Li/Li symmetric cells stably plat and strip for up to 3,600 h at 0.5 mA cm−2 with a constant low overpotential. The LiFePO4/Li cells present up to 90.3% capacity retention and 99.9% coulombic efficiency at 1 C after 500 cycles. Even at a higher current density of 2 C, the cell performs an excellent long-term cycle stability with a capacity decay of only 0.0285% per cycle. More significantly, the assembled coin cells (LiNi0.8Co0.1Mn0.1O2/Li) delivers high capacity retention of 80.2% at 1 C after 500 cycles, and the pouch cell with high cathode loading (10 mg cm−2) and thin lithium anode (∼50 µm) is operated stably. This research provides a very promising strategy to construct a unique organic-inorganic electrolyte with excellent comprehensive properties effectively enabling long-cycle and high-safety LMBs.