Zinc Tailored Cobalt\nPrussian Blue Analogue (PBA)\nas a Prospective Candidate for Supercapacitor Applications

Supercapacitors have recently garnered copious consideration\nin\nenergy storage due to their high power density, incredible stability,\nand long operating life. Prussian blue analogues (PBAs) have attracted\nresearchers’ attention due to the facile modulation of their\natoms without bothering the existing lattice array, and their open\n3D framework aids in ion conduction making it an excellent choice\nfor developing advanced electrode materials. Herein, we report the\nsynthesis of a trimetallic PBA by tuning the concentration of one\nof the metals. First, keeping the core ferricyanide structure intact,\nbimetallic cobalt PBA (Co-PBA) and zinc PBA (Zn-PBA) were prepared,\nyielding a specific capacitance of 96 and 77 F g<sup>–1</sup>, respectively, at 1 mA/cm<sup>2</sup>. However, in a trimetallic\nPBA with both cobalt and zinc introduced into the framework, the net\nspecific capacitance plummeted to a higher value. The as-synthesized\nZn<sub>0.04</sub>Co<sub>0.06</sub>-PBA achieved a specific capacitance\nof 203 F g<sup>–1</sup> at 1 mA/cm<sup>2</sup>, which is an\noverall 211 and 263% increase compared to Co-PBA and Zn-PBA performance,\nrespectively. An asymmetric device achieved a specific capacitance\nof 23 F g<sup>–1</sup> at an operational voltage of 1 V. It\nalso exhibited a capacitance retention of 84.6% after 2230 cycles\nwith 100% Coulombic efficiency. The device yielded an energy density\nof 2.13 W h kg<sup>–1</sup> and a power density of 76.75 W\nkg<sup>–1</sup>, which points out the fact that the developed\nmaterial can truly revolutionize the field of energy storage.