High-Performance Triboelectric Nanogenerators Based on Triazine-Based Covalent Organic Framework/PVDF-HFP Composite Nanofibrous Membranes for Wearable Electronics

Abstract

In this study, triazine-based covalent organic framework (COF)/poly(vinylidene fluoride-co-hexafluoropropylene) (COF/PVDF-HFP) nanofibrous membranes were fabricated via electrospinning and utilized as the negative triboelectric layer in a triboelectric nanogenerator (TENG). The large electronegativity difference between PVDF-HFP and the COF gives rise to an interfacial p–n heterostructure. The polarity disparity at the interface intensifies charge transfer during frictional interactions, leading to increased charge generation. The TPTP-COF- and TPBT-COF-based TENGs generated higher open-circuit voltages (VOC) and short-circuit current densities (ISC) values compared to the TPDA-COF- and TPBTz-COF-based devices, owing to their larger specific surface areas, higher dielectric constants, and more efficient surface charge generation. The optimized TPBT-COF/PVDF-HFP membrane-based TPBT-1.5 TENG achieved maximum VOC, ISC, and transferred charge of 338.2 V, 74.0 μA, and 127.1 nC, respectively. A maximum output power density of 16.76 W m–2 was achieved at an external load resistance of 50 MΩ. Under operating conditions of 60 N applied force at 5 Hz, the COF/PVDF-HFP-based TENG successfully powered LEDs while maintaining stable Voc performance over 20,000 contact–separation cycles. Furthermore, four TPBT-1.5 TENGs connected in series were attached to a custom-made insole and placed inside a shoe. A researcher wore the shoe and performed jogging to generate electrical energy, which was stored in a connected capacitor and subsequently used to power an LED. The developed COF/PVDF-HFP TENG can function as a walk-induced energy-harvesting device, serving as a practical power source for wearable electronic devices.