Reducing and Uniforming the Co₃ O ₄ Particle Size by Sulfonated Graphenal Polymers for Electrochemical Applications

A novel two-dimensional (2D) nanomaterial, namely sulfonated graphenal polymer (SGP), is used to tune the hydrothermal growth of Co₃O₄ nanoparticles. SGP provides abundant nucleation sites to grow Co₃O₄ nanoparticles and effectively reduces the particle size and dimension. As a result, with considering the improved size uniformity of Co₃O₄ and the tight wrapping of SGP around Co₃O₄ as well, the Co₃O₄/SGP hybrid electrode exhibits a high specific electrochemical capacitance of 234.28 F/g at a current density of 0.2 A/g, 237% higher than that of the pure Co₃O₄ electrode. By using the hybrid as the anode of an all-solid-state asymmetric supercapacitor, the capacitance can be well maintained up to 93% after 5000 cycles even at 2 A/g.