Studi Pengaruh Konsentrasi Na-CMC pada Karakteristik Fisikokimia dan Elektrokimia Elektroda Hibrida CNT/NiCo2O4 sebagai Material Superkapasitor Fleksibel

Abstract

The demand for flexible and environmentally friendly energy storage devices continues to grow alongside the development of wearable electronics. Supercapacitors have emerged as one of the most promising candidates due to their high power density, fast charging capability, and excellent cycling stability. However, the performance of supercapacitors is highly dependent on the electrode material used. Therefore, a hybrid CNT/NiCo2O4 electrode was developed by combining the EDLC behavior of CNT with the pseudocapacitive properties of NiCo2O4. Na-CMC was introduced as a flexibility agent to fabricate a flexible electrode material suitable for supercapacitor applications. This study aims to investigate the effect of varying Na-CMC concentrations on the physicochemical, electrochemical, and mechanical properties of CNT/NiCo2O4 hybrid electrodes. The active CNT/NiCo2O4 material was synthesized via a hydrothermal method, and flexible electrodes were fabricated through manual slurry-casting with Na-CMC at mass ratios of 1:1, 1:2, 1:3, and 1:4. Physicochemical characterization was conducted using FTIR, XRD, and FESEM-EDX. FTIR spectra revealed the presence of O-H (3600–3150 cm-1), C=C (1616 cm-1), and C–O–C (1038 cm-1) functional groups from Na-CMC, as well as Ni-O and Co-O vibrations at 641 cm-1 and 552 cm-1 from NiCo2O4. XRD patterns showed diffraction peaks at 2θ = 31.7o, 37.2o, 43.0o, 62.0o, and 65.3o. FESEM images revealed a porous surface with uniformly distributed granular particles, while EDX analysis confirmed the presence of Na, C, O, Ni, and Co elements. Electrochemical tests using CV and GCD indicated that the 1:1 ratio (SC2) yielded the best performance, with the highest specific capacitance of 491.8 mF/cm2 (CV) and 453.6 mF/cm2 (GCD). The SC2 flexible electrode also exhibited excellent mechanical stability under bending up to 180o. The capacitance slightly decreased to 440.1 mF/cm2 at 90o and 422.2 mF/cm2 at 180o, corresponding to a reduction of approximately 6.9% from the initial value. Stability tests over 10 charge–discharge cycles showed high capacitance retention at all bending angles: 97.9% (0o), 97.3% (90o), and 96.8% (180o), indicating that the electrode possesses excellent mechanical and electrochemical stability