In this study, carbon-based polypropylene thermoplastic elastomer (PP-elastomer) composite for current collectors of all-vanadium redox flow battery (VRB) was successfully prepared. The volume resistivity of the PP-elastomer composite was 0.47 Ω·cm. Its tensile strength and elongation at break were 6.6 MPa and 250%, respectively. In addition, good flow property in processing makes this composite has the potential on mass industrial production of current collectors. The single cell and the cell stack of VRB battery equipped with the composite current collectors were assembled for battery tests, including cyclic voltammetry, long-term performance, long-term stability, and the oxidation corrosion. To evaluate the stability and the performance of the cell stack under a long-term operating condition, tests with more than 2300 charge-discharge cycles were carried out. The coulombic efficiency (CE) and voltage efficiency (VE) of the cell stack maintained around 93% and 80% during 2300 charge-discharge cycles, and energy efficiency EE hold around 75%. The results approved that VRB battery equipped the composite current collectors had a good stability and performance. Furthermore, long-term corrosion tests indicated that PP-elastomer composite could endure the strong corrosion of pentavalent vanadium and the concentrated sulfuric acid. The composite materials prepared in this study are more suitable to produce the current collectors. The corrosion resistance of composite materials is much better than that of the graphite, and the mechanism was also discussed.