A superior PVDF-HFP based quasi-solid-state composite electrolyte synergistically reinforced with succinonitrile and W-doped Li1.3Al0.3Ti1.7(PO4)3 for lithium-ion batteries with excellent cycling stability

• PVDF-HFP-SN-LAWTP SCE displays an enhanced electrochemical performance. • The SCE exhibits the good interfacial compatibility with Li anode. • LFP/SCE/Li quasi-solid-state battery shows the excellent cycling performance. Solid polymer electrolytes (SPEs) have excellent flexibility and reliable safety performance, making them promising candidates for lithium-ion batteries (LIBs). While the low ionic conductivity of SPEs has hindered their practical application, the addition of plasticizers or lithium-ion conductors into the SPEs can effectively solve this problem. Herein, a W-doped Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LAWTP) lithium-ion conductor was synthesized, achieving a high room-temperature ionic conductivity of 1.07 mS/cm. Succinonitrile (SN) and LAWTP were added into a poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP) polymer to form PVDF-HFP-SN-LAWTP solid composite electrolytes (SCEs). The optimum SCE shows an ionic conductivity of 1 × 10 −4 S/cm at 50 ℃, which is attributed to the lower crystallinity of PVDF-HFP and high ionic conductivity of LAWTP. Moreover, this SCE has a high lithium-ion transference number of 0.478, a wide electrochemical stability window of 4.8 V, and excellent interfacial stability against lithium. In a cycling test, a Li/SCE/Li symmetric cell can undergo stable lithium striping and plating for 1000 cycles. An LFP/SCE/Li quasi-solid-state battery exhibits an initial discharge specific capacity of 142.69 mAh/g at 0.5C and maintains a capacity retention of 95.60 % after 500 cycles. These results confirm that PVDF-HFP-SN-LAWTP SCE possesses the excellent application potential in LIBs.