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

Herein, leaf-like Co 3 (PO 4 ) 2 was synthesized via a simple and low-cost approach without adding any additional surfactant. Such leaf-like Co 3 (PO 4 ) 2 showed the high crystallinity as proved by spectra analysis. The electrochemical performance of as-synthesized Co 3 (PO 4 ) 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 Co 3 (PO 4 ) 2 nanoflakes are promising materials for potential application in high-performance flexible energy storage devices.