Recently, scientists have been facing major obstacles in terms of improving the performances of dielectric materials for triboelectric nanogenerators. The triboelectric nanogenerator (TENG) is one of the first green energy technologies that can convert random mechanical kinetic energy into electricity. The surface charge density of TENGs is a critical factor speeding up their commercialization, so it is important to explore unique methods to increase the surface charge density. The key to obtaining a high-performance TENG is the preparation of dielectric materials with good mechanical properties, thermal stability and output performance. To solve the problem of the low output performance of PI-based triboelectric nanogenerators, we modified PI films by introducing nanomaterials and designed a new type of sandwich-shaped nanocomposite film. Herein, we used polyimide (PI) with ideal mechanical properties, excellent heat resistance and flexibility as the dielectric material, prepared an A-B-A sandwich structure with PI in the outer layer and modified a copper calcium titanate/polyimide (CCTO/PI) storage layer in the middle to improve the output of a TENG electrode. The doping amount of the CCTO was tailored. The results showed that at 8 wt% CCTO content, the electrical output performance was the highest, and the open-circuit voltage of CCTO/PI was 42 V. In the TENG, the open-circuit voltage, short-circuit current and transfer charge of the prepared sandwich-structured film were increased by 607%, 629% and 672% compared to the TENG with the PI thin film, respectively. This study presents a novel strategy of optimizing dielectric materials for triboelectric nano-generators and has great potential for the future development of high output-performance TENGs.

Cellulose-based insulation paper is widely used in high-voltage equipment, but its limited thermal conductivity and dielectric strength restrict reliable performance under elevated temperatures and strong electric fields. In this work, a dual-phase composite paper is developed by incorporating nano-ZnO and polyimide (PI) into a cellulose matrix, guided by molecular dynamics (MD) simulations. The combined fillers improve interfacial compatibility, suppress void defects, and establish continuous thermal pathways together with stable insulating barriers. Simulation predictions of enhanced thermal transport, charge suppression, and mechanical reinforcement are verified by experiments. The optimized formulation containing 3 wt% nano-ZnO and 6 wt% PI achieves a thermal conductivity of 0.294 W·m⁻¹·K⁻¹, a tensile strength of 72.12 MPa, corresponding to 87.26% and 41.02% improvements over pure cellulose (P0). Meanwhile, the breakdown strength increases from 60.22 to 73.51 kV·mm⁻¹ (+22.07%), and the relative permittivity and dielectric loss tangent decrease to 2.49 (−40.86%) and 0.46% (−43.21%). These results demonstrate that the dual-filler strategy provides a structurally compact and functionally stable composite architecture, enabling simultaneous enhancement of thermal, mechanical, and dielectric properties. This study confirms the effectiveness of simulation-guided design in accelerating the development of multifunctional cellulose-based insulating materials and highlights their potential for application in next-generation high-voltage power systems.

Nano-modified insulating oils have great potential to enhance the dielectric and thermal performance of offshore wind transformers, but nanoparticles are affected by temperature fluctuations to change the oil properties and microstructure, which restricts their large-scale application in offshore wind power equipment. In this study, γ-aminopropyltriethoxysilane (APTES) modified graphene oxide/natural ester composite insulating oil is developed through a surface functionalization strategy. The thermal conductivity and dielectric loss characteristics are systematically evaluated within a wide temperature range, revealing temperature-nanoparticle synergistic interaction mechanisms. Additionally, a model of natural ester insulating oil doped with nanoparticles is constructed based on molecular dynamics (MD) to elucidate the performance enhancement mechanisms, and the performance enhancement mechanism is clarified by calculating the mean square displacement (MSD), free volume (FFV), and radial distribution function (RDF) of the model. Results show that when the temperature rises, the modified nanoparticles can efficiently suppress the diffusion behavior of molecules in the oil, significantly reduce the free volume fraction by filling the gaps between oil molecules, and form hydrogen bonds with water to maintain the number of hydrogen bonds. This work provides theoretical foundations and design guidelines for developing high-temperature-resistant nanocomposite insulating oils.