Light-weight flexible solid-state supercapacitor based on highly crystalline 2D BiOCl nanoplates/ MWCNT nanocomposites

Abstract

Two dimensional (2D) nanomaterials with high specific surface area and large electro-active sites have been promising candidate for flexible electrochemical energy storage applications. Here, we have adopted a simple, cost-effective hydrothermal approach for the synthesis of scalable amount of 2D bismuth oxychloride (BiOCl) nanoplates. Thin flexible films of BiOCl/MWCNT composites have been prepared with varying the weight percentage. A remarkable electrochemical performance has been obtained for BiOCl/MWCNT flexible solid state symmetric supercapacitor (FSSSC) with PVA/H2SO4 gel as solid electrolyte. Among various compositions, 60% BiOCl loaded electrodes (FSSC60) delivers a highest specific capacitance of 421 F/g at 5 mV/s. Furthermore, FSSSC60 exhibits a high energy density of 14.62 Wh/kg at power density 947.5 W/kg compared to previously reported bismuth materials. The FSSSC60 shows excellent durability with 94% of initial specific capacitance after 2000 cycles. In addition, as fabricated device exhibits good flexibility and retains almost constant performance after bending through different angles.