Leaf-inspired quasi-solid electrolyte enables uniform lithium deposition and suppressed lithium-electrolyte reactions for lithium metal batteries

Lithium metal batteries (LMBs) hold great promise for their high energy density; however, the growth of lithium dendrites and continuous lithium-electrolyte reactions have limited their development. Here, we report a leaf-inspired quasi-solid electrolyte (QSE) to homogenize Li-ion deposition and suppress lithium-electrolyte reactions for long-life LMBs. In the leaf-inspired QSE, the thin and robust polyimide network provides mechanical support as “vein skeleton”, in-situ grown MOF crystals self-fill the polyimide skeleton as “mesophyll cells” to form a defect-free MOF membrane, and liquid electrolytes are confined into nano/sub-nano pores of MOF crystals as “blood”. The leaf-inspired QSE with continuous MOF membrane eliminates hazardous intercrystalline diffusion of electrolytes in voids and gaps, and simultaneously enables uniform Li deposition and suppresses lithium-electrolyte reactivity, thus resisting dendrite growth and avoiding severe side reactions. As a result, the leaf-inspired QSE realizes long-life LiFePO4//Li cells with ultrahigh capacity retention of 98.4% after 5000 cycles, and LiNi0.8Co0.1Mn0.1O2//Li cells with capacity retention of 91.5% over 800 cycles, which exhibits the great promise for highly stable LMBs.