Abstract This paper describes the preparation and characterization of CG/Co(OH)2 electrode obtained by electrodeposition of cobalt hydroxide on expanded carbon graphite electrode (CG) for potential application as energy storage devices. The CG electrodes used in this work were obtained from exhausted batteries. Firstly, the CG electrode was submitted to an anodic polarization at 2 V in H2SO4 solution, in order to increase the active surface area at different times. Thereafter, the electrodeposition of the Co(OH)2 was carried out by applying different reduction potentials over different times in order to optimize the electrodeposition process. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy results confirmed the expansion of the bare CG and the Co(OH)2 electrodeposition. Cyclic voltammetry, galvanostatic charge/discharge curves and electrochemical impedance spectroscopy were used to evaluate the electrochemical performance of the modified electrode. It was observed that the parameters of the modification process affect the morphology of the electrodeposited cobalt hydroxide. The best performance was found for the CG/Co(OH)2 modified electrode obtained by CG expanded during 750 s, followed by the electrodeposition conditions of −1.25 V during 250 s, presenting a capacitiy of 3.4 C cm−2 in an applied current density of 1.0 mA cm−2. In addition, this modified electrode also presented a retention capacity of 91% after 1400 cycles.

中文翻译：

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从废旧电池中获得的膨胀碳石墨电极中的电沉积氢氧化钴用作储能装置

摘要 本文描述了通过在膨胀碳石墨电极 (CG) 上电沉积氢氧化钴获得的 CG/Co(OH)2 电极的制备和表征，该电极具有作为储能装置的潜在应用。在这项工作中使用的 CG 电极是从废旧电池中获得的。首先，CG 电极在 H2SO4 溶液中以 2V 进行阳极极化，以增加不同时间的活性表面积。此后，通过在不同时间施加不同的还原电位来进行 Co(OH)2 的电沉积，以优化电沉积过程。扫描电子显微镜、X 射线衍射和拉曼光谱结果证实了裸 CG 和 Co(OH)2 电沉积的膨胀。循环伏安法，使用恒电流充放电曲线和电化学阻抗谱来评估修饰电极的电化学性能。观察到改性过程的参数影响电沉积氢氧化钴的形态。通过 CG 获得的 CG/Co(OH)2 修饰电极在 750 s 期间获得最佳性能，其次是在 -1.25 V 的电沉积条件下 250 s，在外加电流下的容量为 3.4 C cm-2 1.0 mA cm−2 的密度。此外，该修饰电极在 1400 次循环后还具有 91% 的保留容量。观察到改性过程的参数影响电沉积氢氧化钴的形态。通过 CG 获得的 CG/Co(OH)2 修饰电极在 750 s 期间获得最佳性能，其次是在 -1.25 V 的电沉积条件下 250 s，在外加电流下的容量为 3.4 C cm-2 1.0 mA cm−2 的密度。此外，该修饰电极在 1400 次循环后也呈现出 91% 的保留容量。观察到改性过程的参数影响电沉积氢氧化钴的形态。通过 CG 获得的 CG/Co(OH)2 修饰电极在 750 s 期间获得最佳性能，其次是在 -1.25 V 的电沉积条件下 250 s，在外加电流下的容量为 3.4 C cm-2 1.0 mA cm−2 的密度。此外，该修饰电极在 1400 次循环后也呈现出 91% 的保留容量。