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High interface impedance, slow ion transmission, and easy growth of lithium dendrites in solid-state lithium battery are main obstacles to its development and application. Good interface combination and compatibility between electrolyte and electrodes is an important way to solve these problems. In this work, we successfully combined a high ionic conductive polymerized 1,3-dioxolane (PDOL) solid-state electrolyte and a PDOL gel-state electrolyte to form a rigid-flexible composite structural electrolyte and realized the gelation modification of solid electrolyte/electrode interface. This "PDOL SE + PDOL Gel" composite structure not only improves the electrode/electrolyte interfacial contact, reduces the interfacial impedance, but also inhibits the growth of lithium dendrites in the interface between lithium anode and electrolyte by forming an uniform Li-Zr-O and LiF composite protection layer. This composite electrolyte has high ionic conductivity of 5.96 × 10

Low ionic conductivity at room temperature and poor interfacial compatibility are the main obstacles to restrain the practical application of polymer solid electrolytes. In this work, lanthanum zirconate (LZO) fibers were prepared by electrospinning method and used for the first time as fillers in sandwich polypropylene carbonate (PPC)-based solid electrolyte. Meanwhile, a graphite coating was applied on one surface of the composite solid electrolyte (CSE) membrane. The results show that the LZO fibers significantly increases the room-temperature electrochemical performance of the CSE, and the graphite coating enhances the interfacial compatibility between electrolyte and lithium anode. Furthermore, an ultra-thin PPC-LZO CSE with a total thickness of 22 μm was prepared and used in NCM622/CSE/Li solid-state cell, which shows an initial discharge capacity of 165.6 mAh/g at the current density of 0.5C and a remaining capacity of 113.0 mAh/g after 250 cycles at room temperature. Rise to 1C, the cell shows an initial discharge capacity of 154.2 mAh/g with a remaining capacity of 95.6 mAh/g after 250 cycles. This ultra-thin CSE is expected to be widely applied in high energy-density solid-state battery with excellent room-temperature electrochemical performances.

High ionic conductivity, strong stability to lithium metal, convenient preparation and good adaptability to cathodes are the important prerequisites for the practical application of solid-state electrolytes (SE). In this work, an 'environment-friendly' poly(1,3-dioxolane) (PDOL) solid electrolyte membrane was for the first-time prepared by a rapid surface-initiating 1,3-dioxolane (DOL) polymeration process under the interaction of substrate and initiator. The -SiO3, -CaO5 and -NaO3 groups on the surface of glass substrate can react with the oxygen atoms on the DOL ring, initiate the rings opening and polymerizing to be long chains under the action of LiPF6, which provides an efficient and environment-friendly preparation method for PDOL membrane without any organic solvent release, and the monomer conversion rate of the DOL reaches 97.6%. This highly polymerized PDOL electrolyte is friendly to the lithium metal environment and shows strong stability, the Li/SE/Li cell can run stably for nearly 4000 h at a current density of 0.3 mA/cm2. High electrochemical stability window up to 5.0 V enables PDOL electrolyte friendly adapt to various cathode environments including sulfur (S) and LiFePO4, and LiCoO2 and Li(Ni0.6Co0.2Mn0.2)O2 (NCM622). The assembled NCM622/SE/Li solid-state soft-pack battery can be cycled for 300 cycles at 0.5 C with the capacity retention of 85%. This PDOL electrolyte membrane shows a high promising commercial application prospect due to its friendly and high-efficiency polymerization process and strong adaptability to electrodes.