Synthesis of cobalt phosphate nanoflakes for high-performance flexible symmetric supercapacitors

Herein, leaf-like Co3(PO4)2 was synthesized via a simple and low-cost approach without adding any additional surfactant. Such leaf-like Co3(PO4)2 showed the high crystallinity as proved by spectra analysis. The electrochemical performance of as-synthesized Co3(PO4)2 was firstly characterized in a three-electrode system, which shows the specific capacitance of 410 F g− 1 at the current density of 1.0 A g− 1. Furthermore, flexible symmetric supercapacitor was fabricated with PVA-KOH gel electrolyte, exhibiting the specific capacitance of 165 F g− 1 at a current density of 0.5 A g− 1 with a high energy density of 52.8 Wh kg− 1 at a power density of 756 W kg− 1. This superior performance is attributed to the unique morphology and fast surface redox reaction. These excellent results suggested that Co3(PO4)2 nanoflakes are promising materials for potential application in high-performance flexible energy storage devices.