Heterostructured Gel Polymer Electrolyte Enabling\nLong-Cycle Quasi-Solid-State Lithium Metal Batteries

Abstract

For\nrechargeable lithium–metal batteries (RLBs), gel polymer\nelectrolytes (GPEs) are a very competitive and pragmatic option because\nthe special composite structure could restrain the uncontrolled lithium\ndendrite in a liquid electrolyte and avoid the poor interface contact\nfor a solid-state electrolyte. However, the difficulty lies in finding\na delicate balance between ion transport and interface stability.\nHerein, a heterostructured GPE, in which a metal–organic framework\nlayer and an ultrathin Al₂O₃ deposition are\ncoated on the same side of a polymer matrix, is fabricated to homogenize\nlithium ion transport and stabilize the lithium anode interface. With\nthe heterostructured GPE, the Li⁺ transference number is\nimproved to 0.74, and the lithium metal electrode displays an enhanced\ncycle stability over 1000 h. Moreover, Li-rich Mn-based layered oxides,\nthe high-capacity cathode material, are matched for the first time\nwith a lithium–metal anode to assemble a quasi-solid-state\nRLB, which delivers an initial discharge capacity of 257.5 mAh g^–1 with a long-cycle capacity retention of 84.6% after\n500 cycles at a rate of 0.2C.