High performance binary composite (Sr(OH)2/CoO(OH)) thin film for solid state supercapacitor

The fabrication of supercapacitor with efficient power and energy densities with capacity retention is currently leading need in each corner of the globe. In this regard, we have deposited nanoflakes tuberose structured Sr(OH)2/CoO(OH) thin films via layer by layer method over the stainless steel substrate. The crystalline nature and functional groups present in the electrode have been analysed by X-ray diffraction and Fourier transform analysis respectively. The chemical composition and oxidation states present within sample have been vetted via X-ray photoelectron spectroscopy. The nanoflakes grown over the tuberose surface have been revealed by scanning electron microscopy. The electrochemical performance and sustainability of the electrode have been analysed by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The deposited electrode exhibits an excellent specific capacitance of 1544.8 F g−1 and cycle stability ~67% over 12,000 cycles. A solid-state symmetric supercapacitor device, exhibiting outstanding electrochemical performance with a specific capacitance of 155.2 F g−1 and cycle stability ~71% up to 6000 cycles, has been fabricated. This device has a high energy density of 49.9 Wh kg−1 and power density of 7088.5 W kg−1. To show the practical application, blue, green, red, and white coloured light emitting diodes have been illuminated by the fabricated device. These results exhibit that this electrode is a suitable candidate for next-generation energy storage devices. © 2022 Elsevier Ltd