Improving output performance is a key to develop triboelectric nanogenerator (TENG) applications. Herein, an improved melamine foam (MF) /MXene/Ecoflex@TiO2-TENG (FME@TiO2-TENG) based on the composite dielectric MF/MXene/Ecoflex@TiO2 (FME@TiO2) is developed after comprehensively considering charge generation, transport, trapping, and dissipation. A 3D MF framework with evenly dispersed MXene exhibits strong electronegativity, electrical conductivity, and a formation of a large number of micro-capacitances, which are advantageous for surface charge generation, transfer, and retention in the composite dielectric FME@TiO2. More importantly, dual functions of a TiO2 nanotube array film, i.e., its high dielectric property and electron-trapping ability, are beneficial for output of electrical properties. A cathodic protection system powered by the FME@TiO2-TENG was designed to demonstrate its application potential in electrochemistry. Furthermore, a novel in-situ micro-electrolytic cell observation system using K3[Fe (CN)6] as an indicator was designed to evaluate the cathodic protection effect. The results showed that the FME@TiO2-TENG could be used as an independent power source to provide electrochemical cathodic protection. This study provides a useful guidance for a development of the high-performance TENG composite dielectrics and promotes their practical application in the field of the electrochemical cathodic protection.