A friction layer with stability and durability is important to promote the practical application of triboelectric nanogenerators (TENGs). In this work, a two-dimensional cobalt coordination polymer (Co-CP) was successfully synthesized using cobalt nitrate, 4,4',4''-tricarboxyltriphenylamine and 2,2'-bipyridine. To clearly clarify the effect of the doping proportions of Co-CP and the types of composite polymers on the output performance of the TENG, Co-CP was combined with two organic polymers having different polarities (polyvinylidene fluoride (PVDF) and ethyl cellulose (EC)) to form a series of composite films, which were used as the friction electrode materials to fabricate TENGs. Electrical characterizations indicated that a high output current and voltage were obtained from the TENG based on 15 wt.% Co-CP incorporated in PVDF (Co-CP@PVDF), which could be further improved by the Co-CP@EC composite film at the same doping ratio. Furthermore, the optimally fabricated TENG was demonstrated to prevent electrochemical corrosion of carbon steel.