Unveiling the latent potential: Ni/CoFe2O4-loaded electrospun PVDF hybrid composite-based triboelectric nanogenerator for mechanical energy harvesting applications
Hema Malini Venkatesan, Insun Woo, Jae Uk Yoon, Prasad Gajula, Anand Prabu Arun, Jin Woo Bae
Abstract
This study investigates the potential of Ni-doped cobalt ferrite (CoFe₂O₄, N-CF) nanoparticles (NPs)-loaded electrospun poly(vinylidene fluoride) (PVDF) composites for triboelectric nanogenerators (TENGs) to efficiently harness electrical energy from low-frequency mechanical vibrations. PVDF was chosen for its strong electroactive polar phase and inherent tribo-negative properties. Cobalt ferrite (CF) NPs exhibit exceptional charge-trapping capabilities, while nickel’s metallic nature minimizes triboelectric losses due to its conductivity. The synergistic effects of Ni-doped CF (N-CF) fillers enhance charge-trapping efficiency and reduce triboelectric losses, significantly boosting TENG performance. Nickel oxide (NiO), CF, and N-CF NPs were synthesized using a facile co-precipitation method, and PVDF composites were fabricated through electrospinning. The physical and crystalline properties of the composites were characterized using various spectroscopic techniques. Results indicated that incorporating 3 wt% N-CF into PVDF optimized the β -crystalline phase content, crucial for improved output performance. Electrospun PVDF/N-CF (PNC) nanocomposite mats served as the tribo-negative (TN) layer, while aluminum (Al) electrode acted as the tribo-positive (TP) layer in TENG device fabrication. Electrical measurements showed that pristine PVDF/Al TENG devices exhibited lower performance (open-circuit potential— V oc = 22 V, short-circuit current— I sc = 0.61 µA) compared to the optimized Al/PNC3 TENG devices ( V oc = 421 V, I sc = 1.0 µA). The importance of a spacer gap was emphasized, with devices incorporating a spacer gap demonstrating superior performance. The optimized TENG device successfully powered over 30 light-emitting diodes and a stopwatch in real-time applications. This study highlights the exceptional output performance of Al/PNC3-based TENGs and provides valuable insights into the development of next-generation sustainable energy harvesting materials.