Heterostructured Gel Polymer Electrolyte Enabling Long-Cycle Quasi-Solid-State Lithium Metal Batteries
Shaolun Cui, Xuewen Wu, Yang Yang, Minfei Fei, Sheng Liu, Guoran Li,* and Xue-Ping Gao
For rechargeable lithium–metal batteries (RLBs), gel polymer electrolytes (GPEs) are a very competitive and pragmatic option because the special composite structure could restrain the uncontrolled lithium dendrite in a liquid electrolyte and avoid the poor interface contact for a solid-state electrolyte. However, the difficulty lies in finding a delicate balance between ion transport and interface stability. Herein, a heterostructured GPE, in which a metal–organic framework layer and an ultrathin AlO deposition are coated on the same side of a polymer matrix, is fabricated to homogenize lithium ion transport and stabilize the lithium anode interface. With the heterostructured GPE, the Li transference number is improved to 0.74, and the lithium metal electrode displays an enhanced cycle stability over 1000 h. Moreover, Li-rich Mn-based layered oxides, the high-capacity cathode material, are matched for the first time with a lithium–metal anode to assemble a quasi-solid-state RLB, which delivers an initial discharge capacity of 257.5 mAh g with a long-cycle capacity retention of 84.6% after 500 cycles at a rate of 0.2C.