PTFE-Based Triboelectric Nanogenerator with All-Symmetric Tribolayers Enabled by Self-Excited Charge Injection for Highly Corrosive Environments

Conventional triboelectric nanogenerators (TENGs) generally rely on asymmetric contact pairs with pronounced triboelectric-polarity differences, such as polymer/metal combinations, which limits device stability and lifetime in corrosive environments. Herein, we propose an all-symmetric triboelectric nanogenerator (AS-TENG) based on identical polytetrafluoroethylene (PTFE) tribolayers. The AS-TENG consists of two identical Cu/PTFE electrode-dielectric units, so the exposed contact interface is PTFE/PTFE. To overcome the intrinsic output bottleneck caused by the nearly zero triboelectric-polarity contrast of identical-material interfaces, we introduce a voltage multiplier circuit (VMC)-assisted self-excitation strategy to promote charge injection. Under the same PTFE film thickness and contact separation conditions, the AS-TENG achieves a peak current of 71 μA, which is approximately 61% higher than that of a conventional PTFE/Al TENG. This all-symmetric strategy is further shown to be applicable to other polymer systems. By replacing the exposed heterogeneous contact interface with a chemically identical PTFE/PTFE interface, the device exhibits improved corrosive environment tolerance while maintaining a stable mechanical output; the PTFE-based AS-TENG retains approximately 70% of its output after a 40 h immersion in strong acidic and alkaline solutions. A self-powered floor based on the AS-TENG principle transfers 15 μC per cycle. This work provides a practical route for enhancing identical tribolayer TENGs through VMC-assisted self-excitation and expands the structural design space of TENGs for energy harvesting under corrosive operating conditions.