Boosting Output Performance of Triboelectric Nanogenerator via Interface Self-Regulation Strategy

Abstract

The long-term durability of triboelectric nanogenerators (TENGs) remains a critical challenge for their practical deployment. Although approaches like reducing interfacial friction or contact duration can enhance durability, they often compromise electrical performance. The charge self-excitation method can improve the output performance. However, when it is introduced into the sliding mode with small capacitance change, it increases the complexity of the circuit and cannot solve the problem of charge attenuation caused by material wear. Herein, we propose a self-regulation strategy that concurrently controls the interface contact state and contact force. This approach synergistically combines the advantages of both sliding and contact-separation configurations, enabling the triboelectric materials to micro-slide and deform adaptively, ensuring stable dynamic interfacial contact under minimal normal pressure. Such a mechanism promotes strong electron cloud overlap at the microscale, thereby enhancing charge transfer efficiency. Compared to conventional TENGs, the self-regulating TENG achieves a 72.5-fold reduction in frictional force and a 13-fold increase in energy output. Furthermore, a wireless self-powered sensing system is integrated, achieving a power density of 242.4 mW/m² under real water flow conditions. The system maintains 97.6% of the initial output after 10 h of continuous operation, confirming the practical feasibility of the proposed approach. This work presents a universal method to enhance the electrical performance and durability of TENGs, paving the way for their broader application.

Fig. 1.

Implementation strategy and working mechanism of SR-TENG. (A) Output performance and wear of TENG as a function of contact force: small force (i), large force (ii), and their interrelationship (iii). (B) Conceptual diagram of implementation process of the interface self-regulation strategy: insufficient contact (i), sufficient contact (ii), and minimal contact force maintenance (iii). (C) Structure scheme (i) and working mechanism (ii) of SR-TENG. (D) Performance enhancement mechanism via DFT simulation calculation. (E) Configuration of CF-TENG and SR-TENG. (F) Output charge comparison of CF-TENG and SR-TENG. Comparison of (G) energy and (H) driving force between CF-TENG and SR-TENG.

Fig. 2.

Results of increasing output performance and parameter optimization for SR-TENG. (A) Comparison of output charge (i), voltage (ii), and current (iii) between CF-TENG and SR-TENG under different interface contact forces. (B) Comparison of output energy between CF-TENG and SR-TENG. (C) Self-regulation effect of SR-TENG on driving force. (D) Comparison of durability between CF-TENG and SR-TENG. (E) Structural parameter diagram of single-layer SR-TENG. Dependence of SR-TENG output charge and voltage on (F) freestanding layer substrate thicknesses, (G) distances between 2 electrodes, and (H) layout angles. SR-TENG output charge and output voltage at various (I) electrode areas and (J) sliding distances.

Fig. 3.

Multi-layer SR-TENG electrical output. (A) Experimental measurement platform schematic. The (B) charge and (C) voltage outputs of SR-TENG at various number of layers and slider drag. (D) Output charge and driving force of SR-TENG by different layer numbers at 1.2-N slider drag. (E) Output charge and output current of SR-TENG at variable excitation frequencies. (F) Multi-layer SR-TENG output current at varying strokes. (G) Charging curves of multi-layer SR-TENG for capacitors with different capacitances. (H) Multi-layer SR-TENG output power density under various external loads.

Fig. 4.

Electrical output evaluation under water flow conditions. (A) Schematic diagram of the integrated prototype. (B) Spring-damp system model of the designed prototype in water flow. (C) Amplitude of the bluff body with various spring stiffness. (D) Bluff body frequency at varying spring stiffness. Prototype (E) output charge and (F) current under various flow velocities. (G) Power density of the prototype at various external loads under 0.64 m/s flow velocity. (H) Prototype output current variation during continuous operation for 10 h in water flow. (I) SEM images of Nylon and FEP film before (i and ii) and after (iii and iv) durability testing.

Fig. 5.

Application demonstration of the designed prototype. (A) Conceptual illustration of a wireless self-powered sensing system for water environment. (B) Circuit diagram of the prototype with a PMC. (C) Comparison of the capacitor charging speeds with and without the PMC. (D) Photo of the wireless self-powered sensing system. Voltage curves of (E) the wireless self-powered water temperature, (F) water level, and (G) water quality sensing process.