Dendrite-Free Solid-State Li–O2 Batteries Enabled by Organic–Inorganic Interaction Reinforced Gel Polymer Electrolyte

Gel polymer electrolytes (GPEs) have received extensive attention due to their excellent nonflammability, leak prevention, and low cost. However, low ionic conductivity at room temperature and poor interfacial stability hinder the further application of GPEs. Here, a novel GPE based on PVDF-HFP/PMMA/SiO2 (PPSE-X, X represents the mass percentage of SiO2 in the GPE) is designed and fabricated. The synthesized PPSE-15 demonstrates an organic–inorganic double complexation structure, in which two kinds of polymer cross-link, leading to the increase of lithium-ion migration amount (tli+) in PPSE-15. Moreover, polar functional group (Si–O) in the nanometer SiO2 promotes the lithium salt dissociation, regulates the Li+ deposition and thus inhibits the production of lithium dendrite. The Li/PPSE-15/Li symmetric cell can run steadily for more than 750 h at a current density of 0.5 mA cm–2. Not only that, the Li–O2 battery assembled with PPSE-15 as an electrolyte can operate over 300 cycles at room temperature. After full charge and discharge for 5 cycles, the capacity retention reaches 48.3%. In addition, the existing PPSE-15 demonstrates excellent safety and flexibility and shows great potential in high-performance Li–O2 batteries.