► A novel single-ion conducting polymer electrolyte, lithium polyvinyl alcohol oxalate borate (LiPVAOB), was prepared. ► It is from the reaction of poly(vinyl alcohol) with boric acid, lithium hydroxide and oxalic acid. ► The prepared materials act as single-ion polymer electrolytes. ► Their electrochemical window can be stable up to 7V (vs. Li+/Li). ► They are of great attraction for high voltage lithium ion batteries with high energy density. In this study, a novel single-ion conducting polymer electrolyte, lithium polyvinyl alcohol oxalate borate (LiPVAOB), from the reaction of poly(vinyl alcohol) (PVA) with different molar ratio of boric acid, oxalic acid and lithium carbonate was prepared. The prepared materials were characterized by Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), differential thermal analysis (DTA), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry. Ionic conductivity of these polymer electrolytes from adding an assistant (about 20wt.% propylene carbonate) is dependent on molar ratio of the reactants and can up to 6.11×10−6Scm−1 at ambient temperature. Their electrochemical window can be stable up to 7V (vs. Li+/Li), which is of great attraction for high voltage lithium ion batteries with high energy density.