Cathodic protection is one of the effective methods for metal protection, but it faces issues such as the use of an external power supply or the need for repeated charging. The self-powered metal corrosion prevention system based on triboelectric nanogenerator (TENG) is a viable solution to address the power supply issues in traditional methods. However, the low surface charge density of traditional triboelectric materials poses a challenge to the practical application of TENGs. Herein, we successfully modulated the dielectric constant and surface roughness of poly(vinyl chloride) (PVC) by incorporating Bi2Ti2O7 nanoparticles, and fabricated a Bi2Ti2O7/PVC composite triboelectric material with a surface charge density of 711 μC/m2, which is 108% higher than that of pure PVC film. The 1.5 wt % Bi2Ti2O7/PVC-based TENG can generate alternating current (AC) signals up to 416 V and a current of 55 μA, and it only requires 13 s to charge a 1000 μF capacitor from 0 to 3 V. Furthermore, the device maintains good operational stability after 20 h of continuous operation. The self-powered metal corrosion protection system based on 1.5 wt % Bi2Ti2O7/PVC composite film can effectively protect iron sheet and 45 steel sheet in simulated seawater. This research not only offers a reference for the creation of triboelectric materials with high surface charge density but also demonstrates the application of high-performance TENG in metal corrosion protection systems.