Triboelectric nanogenerator (TENG) has been widely researched and used for sustainable energy, sensing and other applications in recent years due to its energy conversion properties. However, in practical applications, TENG is often exposed to complex and harsh environments, so ensuring its stable output performance is a significant challenge. Here, a flexible, superhydrophobic and environmentally resistant TENG for energy harvesting and self-powered sensing is proposed by a cost-effective surface modification and co-blending method. The roughness, hydrophobicity and surface potential of the composites are significantly enhanced by the introduction of surface modified BN (m-BN), resulting in excellent triboelectric output (43 W/m2) of the m-BN/TENG. Moreover, the m-BN/TENG not only maintains 90% initial electrical output at 80% humidity but also its output performance has no noticeable change after treatment with acid and alkali. Apart from energy harvesting, the TENG has been demonstrated as a self-powered humidity sensor with a sensitivity of − 80 nA RH−1 and a self-powered droplet detector with an ultra-fast response time of 0.6 ms. Our work provides a practical approach for stable energy harvesting and self-powered sensing of TENG in harsh environments.