A cerium-doped NASICON chemically coupled poly(vinylidene fluoride-hexafluoropropylene)-based polymer electrolyte for high-rate and high-voltage quasi-solid-state lithium metal batteries

The isolated inorganic particles within composite polymer electrolytes (CPEs) are not correlated to the Li+ transfer network, resulting in the polymer dominating the low ionic conductivity of CPEs. Therefore, we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors (NASICON) Na1.3+xAl0.3CexTi1.7-x(PO4)3 (NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide (LiTFSI) matrix. A strong interaction between Ce3+ from NCATP and TFSI- anion from the polymer matrix contributes to the fast Li+ transportation at the interface. The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 x 0-3 S cm-1 and a Li+ transference number of 0.88. A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm-2 presents outstanding cycling stability over 2000 h at 25 degrees C. The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO4 at 2 C after 400 cycles and Li/CPEs/LiCoO2 at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g-1 at 25 degrees C, respectively. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

A novel quasi-solid-state composite polymer electrolyte with high ionic conductivity and excellent cycling stability has been developed for lithium metal batteries.