Peranan Pengikat Na-CMC terhadap Karakteristik Fisikokimia dan Kapasitansi Spesifik Elektroda Hibrida rGO/Co3O4 Sebagai Material Superkapasitor

Abstract

The increasing global energy demand drives the development of efficient and sustainable energy storage technologies. Supercapacitors are considered a promising solution due to their high power density and long-term stability, although optimizing electrode materials to improve performance remains a challenge. Hybrid materials such as rGO/Co₃O₄ combine high electrical conductivity and large capacitance, but issues related to material distribution and stability still need improvement. The use of environmentally friendly binders such as sodium carboxymethyl cellulose (Na-CMC) is expected to enhance the homogeneity and electrochemical performance of electrodes. The research was conducted in four stages: synthesis of GO via a modified Hummer’s method, synthesis of rGO/Co3O4 hybrid through hydrothermal and calcination processes, preparation of rGO/Co3O4 hybrid electrodes by mixing, and analysis of physicochemical and specific capacitance properties using different rGO/Co3O4:carbon black:Na-CMC ratios (85:10:5, 80:10:10, 75:10:15, and 70:10:20 wt%). XRD analysis revealed GO peaks at 2θ = 10.84° and rGO at 26.69°, along with eight Co3O4 peaks (19.17°–65.20°) corresponding to spinel structures. FESEM showed porous morphology with Co3O4 nanorods dispersed on rGO surfaces. EDX identified evenly distributed C, O, Co, and Na elements. Raman spectra exhibited D (1340–1345 cm⁻¹) and G (1603–1606 cm⁻¹) bands and five Co3O4 modes, with ID/IG increasing from 1.077 (GO) to 1.145 (rGO/Co₃O₄), then decreasing to 1.055 in the electrode due to graphitization by carbon black and Na-CMC. FTIR confirmed the presence of O–H, C=O, C=C, C–OH, C–O, and Co–O groups. CV and GCD results showed that increasing Na-CMC ratio improved electrode’s specific capacitance, with the optimum at E3 (75:10:15 wt%), reaching Cs = 322.3 F/g at 5 mV/s and Cm = 191.6 F/g at 0.1 A/g.