Synergistic Enhancement of WO₃@Co₃O₄ Layered Supercapacitors via PAA-Directed Electrodeposition: A Comparative...

In this study, a novel layered WO₃@Co₃O₄ composite electrode was synthesized via a controlled electrodeposition method employing different surfactants to finely tune its nanostructure. The incorporation of polyacrylic acid (PAA) surfactant yielded an optimized P-W@Co electrode with a hierarchical porous morphology and reduced crystallite size, markedly enhancing electroactive site exposure and electron transport. Structural analyses confirmed the amorphous nature of WO₃ and crystalline spinel Co₃O₄ phases forming an integrated composite architecture. Electrochemical characterizations in a three-electrode system revealed that the P-W@Co electrode exhibited superior pseudocapacitive behavior, with an areal capacitance of 11.70 F/cm² at 20 mA/cm² and excellent rate capability, retaining 80% capacitance at 40 mA/cm². Kinetic studies demonstrated enhanced diffusion-controlled charge storage attributed to improved ion accessibility and charge transfer kinetics. To evaluate practical feasibility, asymmetric supercapacitor devices incorporating P-W@Co as the positive electrode coupled with activated carbon as the negative electrode were fabricated. This device showcased a widened operational voltage (1.5 V), outstanding areal capacitance (211 mF/cm²), and energy density (0.066 mWh/cm²). Importantly, the device exhibited exceptional cycling stability, retaining 81.8% capacitance after 7000 cycles. This work signifies a major advancement in surfactant-mediated design of WO₃@Co₃O₄ layered electrodes for scalable, high-performance supercapacitor applications, combining structural stability, enhanced conductivity, and multifaceted charge storage mechanisms.