Facile construction of copper nanoparticles decorated 3D calcium titanate toward tunable high dielectric and energy storage epoxy composites

With the continuous development of semiconductor power electronic devices and the rising operating frequencies of systems such as 5G, there is an urgent need for energy storage units that exhibit high dielectric constants and energy densities while simultaneously reducing dielectric losses. Achieving this optimization is critical for mitigating thermal failure in electronic devices and enhancing their operational reliability and service life. A 3D CTO-Cu/epoxy (EP) dielectric composite has been successfully fabricated by reverse-infiltrating epoxy into a pre-constructed 3D network of calcium titanate (CTO) decorated with copper nanoparticles. The continuous 3D CTO architecture, created via a facile sol-gel process, ensures uniform distribution of copper (Cu) nanoparticles throughout the structure, synergistically enhancing the overall performance of 3D CTO-Cu/EP composite. Moreover, in virtue of the equivalent micro-capacitors and the Coulomb-blockade effect generated by the Cu nanoparticles, the dielectric properties of the 3D CTO-Cu/EP composites were significantly enhanced, while the dielectric loss was simultaneously and effectively suppressed—an achievement that is particularly challenging to realize. The 3D CTO-0.2Cu/EP system achieved the highest dielectric constant of 28.0 (at 1 kHz) and the lowest dielectric loss of 0.021, which are 184 % and 70 % improvements over the 3D CTO/EP composite, respectively, offering an effective method to adjust the dielectric and energy storage properties of polymer-based dielectrics.