The development of a high-performance polymer for a robust droplet-based triboelectric nanogenerator (RD-TENG) is crucial for sustainable energy harvesting and adaptive sensing applications in harsh environments. However, achieving thermal and chemical stability of dielectrics and induction electrodes remains a challenge. This study addresses these requirements by leveraging the intrinsic properties of polyether ether ketone (PEEK), which enables semicrystalline composites integration through a thermal bonding technique. The rigid molecular backbone of the PEEK and crystalline regions formed by its orderly arrangement impart thermomechanical properties and chemical stability. Incorporating multiwalled carbon nanotubes allows for tailoring low surface resistance and mechanical reinforcement. The results demonstrate a high glass transition temperature of 160 °C and structural integrity at 300 °C, along with exceptional durability and electrical performance under long-term salt spray, a wide pH range, and organic solvents. This work offers a valuable strategy for fabricating RD-TENG and promotes advancements in harsh environments.