A novel lithiated polyvinyl formal single-ion conductor (Li-PVFM) membrane has been proposed and prepared as polymer electrolyte for Li-ion batteries with excellent mechanical strength of 11-34 MPa and good thermal stability, but the series faces the common issue of solid-state electrolyte - a low ionic conductivity about 10(-6) S cm(-1) at room temperature. Herein, by purifying the polymer matrix to avoid the negative effect of the impurities on Li+ diffusion, and linking more Li+ from lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) on the matrix to improve the carrier concentration, the as obtained solid-state electrolyte membrane exhibits a significantly improved ambient ionic conductivity in two orders of magnitude to 10(-4) S cm(-1). The results confirm that the polymer matrix is obtained without any residual oxalate and carbonate, resulting in the increasing ionic conductivity of electrolyte membrane from 10(-6) to 10(-5) S cm(-1). Furthermore, the conductor membrane with modulating the lithium content to 0.80 mol L-1 has a high lithium-ion transference number of 0.81, wide electrochemical stability window of > 5 V (vs. Li+ /Li) and excellent tensile strength of 44.8 MPa. The solid electrolyte batteries using LiFePO4 as cathode material exhibit a reversible capacity of 130 mAh g(-1) and a good cycling stability.