Triboelectric nanogenerators (TENGs) are emerging as a promising, cost-effective energy harvesting approach for Internet of Things (IoT) applications. However, their practical deployment faces challenges due to extremely high output voltages, ultra-low intrinsic capacitance, the necessity for non-self-powered interface circuits, and ultra-low transfer efficiency due to output voltage asymmetry.

Addressing these issues, this research introduces a novel dual-output rectifier (DOR)-based interface circuit designed to efficiently convert TENG outputs into two different voltage levels, optimizing energy harvesting and switching generation. Our approach leverages energy from the TENG's transition from separation to contact in the negative half cycle to produce a step-down switching control signal. Concurrently, energy generated during the positive half cycle, from contact to separation, is temporarily stored at a high voltage level. This energy is later stepped down and directed to the load via a flyback converter, upon reaching a threshold that activates the control module, optimizing energy transfer efficiency.

The effectiveness of our approach was demonstrated using self-manufactured vertical contact-separation TENGs (CS-TENGs) featuring a spring-assisted separation structure comprising two copper sheets and a polytetrafluoroethylene (PTFE) sheet, which occupies a 120mm × 90mm effective contact area. The PTFE layer is 0.1mm thick, allowing for a maximum displacement of 1.2mm in our experiments. The experimental results demonstrate significant improvements, achieving 2.75 and 2.34 times the maximum output power compared to a full-wave rectifier (FWR)-based design at 2 Hz and 3 Hz, respectively. Additionally, under the same frequency and load conditions (1MΩ at 2 and 3 Hz), the output gains are 152 and 160 times greater than the FWR's. 

Our approach brings about a significant advancement in integrating TENGs for low-frequency and low-load IoT devices, demonstrating its potential for wider practical application. The corresponding achievements have been accepted for publication in IEEE Transactions on Power Electronics.