Liquid Capacitor Based on Hafnium Oxide

Abstract

In this work, we synthesize Hafnium (IV) oxide (HfO2) ink from hafnium chloride (HfCl4) powder assisted with deionized water. The poly acrylic acid (PAA) is used as surfactant to decrease the surface tension. Conversion of HfCl4 into HfO2 was detected by Raman spectroscopy and energy dispersive X-ray spectroscopy (EDS) characterization techniques. This proposed ink can be easily synthesized at a low temperature. Using the synthesis ink, a liquid capacitor is proposed, which is tested for electrochemical analysis. Indium tin oxide (ITO) coated PET is used as bottom and top current collector electrode, polydimethylsiloxane (PDMS) mold is used as separator, and HfO2 ink is used as aqueous electrolyte. Liquid capacitor is also tested on different bending diameters using bending machine from flat down to 10 mm bending curvature, which shows a stable capacitor function.