A promising TPU/PEO blend polymer electrolyte for all-solid-state lithium ion batteries

[Display omitted] •Solid polymer electrolyte based on TPU/PEO is prepared by polymer blending technique.•The mechanical stability and the electrochemical properties of the SPE is improved by TPU.•All solid state battery based on TPU/PEO SPE shows attractive discharge capacity and outstanding cycling stability. Solid polymer electrolyte (SPE) membranes composed of thermoplastic polyurethane (TPU), poly(ethylene oxide) (PEO) and lithium bis(trifluoromethane sulfonimide) (LiTFSI) are prepared and investigated in this work. The results show that addition of TPU to the blend polymer results in loss of the crystallinity of PEO and improve the dissolution of lithium salts into the SPE matrix. TPU can also improve the mechanical stability and the electrochemical properties. Among the TPU/PEO blend electrolytes, the TPU/PEO=1:3 based electrolyte presents an ionic conductivity of 5.3×10−4Scm−1 with electrochemical stability above 5V (vs. Li+/Li) at 60°C. The LiFePO4/SPE/Li coin cell based on SPE (TPU/PEO=1:3) is assembled and shows the attractive discharge capacity (140 and 154mAhg−1 at 0.2C under 60 and 80°C, 112 and 127mAhg−1 at 1C under 60 and 80°C) and outstanding cycling stability (close to 96% and 94% after 100th cycles at 1C under 60 and 80°C), respectively. These results demonstrated that the TPU/PEO blend polymer electrolyte should be a promising electrolyte for all-solid-state lithium ion batteries.