Li1.4Al0.4Ti1.6(PO4)3 nanoparticle-reinforced solid polymer electrolytes for all-solid-state lithium batteries

The applications of solid polymer electrolytes in all-solid-state Li-ion batteries are restricted by their low ion conductivities at room temperature and poor mechanical and thermal stabilities. Herein, Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 (LATP) electrolyte nanoparticles were used as active fillers to improve the properties of polyethylene oxide (PEO)-based electrolytes. The ion conductivity of the composite electrolyte with 1 wt% LATP increased to 1.2 × 10 −5  S/cm at room temperature, because of the effective inhibition of the PEO matrix crystallization by the high-conductivity LATP nanofillers . The electrochemical, mechanical and thermal stabilities were also enhanced by the LATP nanofillers. The LATP-filled composite electrolytes can effectively block Li dendrites in symmetric Li/electrolyte/Li cells during repeated Li stripping/plating with a current density of 0.10 mA/cm 2 for 600 h at 30 °C. Furthermore, the LATP-based all-solid-state LiFePO 4 /Li cells exhibited higher reversible capacity (152 mAh/g at 0.10 C), cycling stability (84% after 20 cycles at 50 °C) and rate capability than the LATP-free cells.