As a new approach of collecting friction energy, triboelectric nanogenerators (TENGs) have shown promising applications in many fields. However, the most TENGs based on organic polymer materials often suffer from durability problems of aging, wear, and low output performance. Here, a novel inorganic coating TENG based on normal microarc oxidation coating (FM-TENG) is constructed and designed for wave energy collection and in situ self-powered cathodic protection against corrosion. After fluorination treatment, FM-TENG exhibits good output performance with a maximum short-circuit current density of 3 mA/m2 and power density of 2 mW/m2, which is 3–5 times larger than that of Teflon film-based TENG that is commonly used as the best solid–liquid triboelectrification material. As a high-output coating, TENG can be easily coated on the surface of marine equipment, such as ships, to collect wave energy in situ for energy supply or self-powered cathodic protection. More importantly, TENG with inorganic coating as the friction material possesses high wear resistance and long-term stability. When FM-TENG is damaged in a complex marine environment, it can self-healing by releasing fluoride in the pores of the microarc oxidation coating, and a self-healing FM-TENG is achieved. This new type of inorganic coating TENG has great potential applications in the field of ocean wave energy harvesting, energy supply, and self-powered devices.