Performance of ultrafine silver chromate particles in electrochemical capacitors for low-pass frequency filtering applications

Electrochemical capacitors or supercapacitors have become a prominent area of research in energy storage because of their extended cycle life and rapid electrochemical performance along with significant energy and power density. This report provides a comprehensive synthesis and analysis of silver chromate (Ag₂CrO₄) nanoparticles and investigates their electrochemical performance as an electrochemical capacitor. Ag₂CrO₄ is a chemically stable material that exhibits high electrical conductivity and low solubility, making it an ideal candidate for supercapacitor applications. Nanosized Ag₂CrO₄ was synthesized using an organic molecule mediated complexation route where particles ranging from 10 to 30 nm in size are encapsulated within the organic matrix. For the Ag₂CrO₄-based three-electrode system, at a scan rate and current density of 5 mV s^-1 and 3 A g^-1, the specific capacity values obtained were 131 and 203C g^-1, respectively. An asymmetric supercapacitor device was fabricated utilizing Ag₂CrO₄ as the cathode and activated carbon as the anode material, which displayed a specific capacity of 36C g^-1 at 0.4 A g^-1 and 31C g^-1 at 10 mV s^-1. The assembled device displayed a maximum power density of 361 W kg^-1 at an energy density of 1.5 Wh kg^-1. The performance of the device was successfully demonstrated by powering a red LED, confirming its capability as an energy storage component. Furthermore, the ability of the device to attenuate high-frequency signals was demonstrated through its integration into a resistor-capacitor (RC) circuit, where it operated as a low-pass filter, emphasizing its potential for use in frequency-selective electronic applications.