文摘
A hybrid capacitor comprising mixed transition-metal sodium phosphate/activated carbon (AC) with sodium hydroxide electrolyte is reported for the first time. The sodium phosphate (maricite, NaMn1/3Ni1/3Co1/3PO4) positive material was prepared by both urea-assisted combustion and polyvinyl pyrrolidone (PVP)-assisted sol鈥揼el syntheses. The electrochemical behavior of maricite and AC was characterized by cyclic voltammetry (CV) and charge鈥揹ischarge methods. The reaction mechanism at the maricite electrode in NaOH(aq) electrolyte appears to be reversible, involving a faradaic process, while the AC shows capacitive behavior involving a non-faradaic process. The aqueous hybrid capacitor, maricite (as the cathode), and AC (as the anode) studied by galvanostatic (charge鈥揹ischarge) cycling in the range of 0鈥?.6 V at 0.5 A g鈥? exhibited a specific discharge capacitance of 45 F g鈥? stable over 1000 cycles.