It is prepared by mixing inorganic solid electrolyte (Li.3Al0.3Ti1.7(PO4)3), organic polyoxyethylene (PEO) and boronized polyethylene glycol (BPEG) in a ratio of 7:1.5:1.5 The inorganic-organic composite solid electrolyte (CSE-B-71515).

　　The next generation of lithium batteries for electric vehicles and mobile phones will choose all-solid-state lithium-ion batteries with higher energy density and better safety. In order to accelerate the research and development of new materials and all-solid-state lithium-ion batteries, our country established the “Material Genome Technology” national key research and development plan for the first time during the “13th Five-Year Plan” period, and hopes to pass the high-throughput calculation, synthesis, detection and database of the material genome ( Big data machine learning and intelligent analysis) new concepts and new technologies to accelerate the research and development of all-solid-state lithium-ion batteries, and set up a national key special project of “All-solid-state battery research and development based on material genome technology”, which is sponsored by Peking University Shenzhen Graduate School As the chief scientist, Professor Pan Feng of the School of New Materials took the lead in organizing the joint responsibility of 11 units.

　　An important part of the project's research and development includes the research and development of new solid electrolytes and the control of each interface of solid-state battery materials. Solid electrolytes are mainly divided into inorganic solid electrolytes, solid polymer electrolytes and composite solid electrolytes. Traditional solid polymer electrolytes have low conductivity near normal temperature and a narrow potential window, while inorganic solid electrolytes have poor flexibility and large interface impedance. As a combination of the two, the composite solid electrolyte not only has flexibility, but also has good electrical conductivity at relatively low temperatures, and has broad research prospects.

　　Professor Pan Feng's research group has recently made important progress in the research of composite solid electrolytes and interface regulation. It is prepared by mixing inorganic solid electrolyte (Li.3Al0.3Ti1.7(PO4)3), organic polyoxyethylene (PEO) and boronized polyethylene glycol (BPEG) in a ratio of 7:1.5:1.5 The inorganic-organic composite solid electrolyte (CSE-B-71515). The three components play their own roles. The inorganic solid electrolyte provides a channel for lithium ions, and can also make the composite solid electrolyte have higher mechanical strength; the organic macromolecule PEO can not only conduct lithium ions, but also act as a bonding ceramic The role of particles; the organic small molecule BPEG first reduces the crystallinity of PEO, and secondly changes the hard contact between the solid-solid interface into a soft contact, which can make the deposition and extraction of lithium on the metal lithium more uniform. By having the above characteristics, the electrolyte can well physically and chemically block the generation of lithium dendrites. In addition, the composite solid electrolyte was electrochemically tested at 60 degrees Celsius using the lithium iron phosphate and metal lithium of the solid-state battery as the positive and negative electrodes. The specific capacity was 158mAhg-1 at a rate of 0.1C and a specific capacity of 158mAhg-1 at a rate of 2C. Specific capacity of 94mAhg-1. This research has important guiding value for the study of solid electrolytes.