Solid polymer electrolyte based on thermoplastic polyurethane and its application in all-solid-state lithium ion batteries

In this paper a new kind of solid polymer electrolyte (SPE) based on thermoplastic polyurethane (TPU) is fabricated. With the dispersion of Li 7 La 3 Zr 2 O 12 powders, the lithium ionic conductivity of the SPE can be improved effectively. By optimizing the amount of Li 7 La 3 Zr 2 O 12 , an ionic conductivity of 8.89 × 10 − 5 S cm − 1 at 80 °C is achieved. X-ray diffraction and scanning electron microscopy are employed to analyze the crystallinity and microstructure of the SPE samples. The all-solid-state lithium ion cells with the TPU-based SPE as solid electrolyte and LiFePO 4 as active cathode material are assembled through a simple blade-coating method. Such all-solid-state cells exhibit a specific capacity (160 mAh g − 1 ) comparable with the traditional cells using organic liquid electrolyte at the current density of 5.3 μA cm − 2 . To further investigate the electrochemical performances of the all-solid-state cells, the cyclic voltammetry and galvanostatic cycling are also performed and analyzed. • TPU-Li 7 La 3 Zr 2 O 12 hybrid solid electrolyte exhibits a high ionic conductivity. • An all-solid-state cell based on TPU solid electrolyte is assembled and evaluated. • LFP/solid electrolyte/Li cells deliver a high capacity of 160 mAh g − 1 .