Synthesis of Core-Shell Based Artificial Nanodielectrics Via Scalable and Cost Effective Methods

R. Singh, N. Badi
University of Houston, US

Keywords: nanodielectrics, energy storage, capacitors, core-shell, nanoparticles

Summary:

We have previously reported K value of 20 and breakdown field of 50V/µm as measured for a dielectric samples with 10% loading of M@SiO2 core-shell nanoparticles (NPs) in polyvinyl pyrrolidone (PVP). Resulting capacitance value of 11.5nF/In2 is in par with commercially available capacitor devices. However, elaborated synthetic methods developed so far were time consuming in addition to higher processing costs. This paper reports on the development of cost effective two fabrication methods to mass produce high energy storage capacitors using artificial “nanodielectrics” material. First method calls for a modified aqueous sol-gel route based on power ultrasound technique for silica coating of metal nanoparticles. In this approach, organosilanes with required functional groups were first used to cover the surface of metal nanoparticles. Subsequent silica coating was performed through ultrasonic processing in an aqueous mixture of surface treated nanoparticles and appropriate silane. In the second method, The metal nanoparticles coated metal nanoparticles (M-NPs) were easily encapsulated by polymer such as polystyrene spheres (PS). Swelling of PS microspheres in acetone in the presence of M-NPs resulted in the formation of the M-PS core-shell nanostructures. These core-shell structures maintain their integrity when re-suspended in water. Tests were performed by XEM/TEM morphology, thermal and frequency experiments.