Abstract Recently, hybrid capacitive deionization devices have gathered much attention due to high ion removal capacity, rapid ion capture and excellent stability. In this study, sodium ion battery material-reduced graphene oxide/cobalt oxide (rGO/Co3O4) has been successfully synthesized and investigated as a potential cathode for hybrid capacitive deionization (HCDI) systems for the first time. The structure and morphology of rGO and rGO/Co3O4 composites have been analyzed using XRD, FT-IR, TGA and SEM. The characterization confirms the homogeneous crystal growth of Co3O4 on the rGO sheets, with rGO weight % of 9.4 (rGO/Co3O4-A) and 25.2 (rGO/Co3O4-B). The cyclic voltammetry studies indicated that the rGO/Co3O4-B electrode exhibited high specific capacitance (210 F g−1 at 5 mV s−1) with redox properties. This paper also investigates the influence of initial concentration and voltage on the ion removal capacity of the rGO and rGO/Co3O4 composites. The rGO/Co3O4-B based HCDI system presents a significantly high ion removal capacity of 18.63 mg g−1 (250 mg L−1, 1.6 V), which is 2.8 times higher than pure rGO based CDI system (6.45 mg g−1). Also, the rGO/Co3O4 composites exhibited excellent regeneration ability indicating its potential use in high performance CDI systems.

中文翻译：

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用于混合电容去离子系统的新型石墨烯/Co 3 O 4 复合材料的开发

摘要 近年来，混合电容去离子装置因其高离子去除能力、快速离子捕获和优异的稳定性而备受关注。在这项研究中，钠离子电池材料还原的氧化石墨烯/氧化钴（rGO/Co3O4）已被成功合成并首次被研究为混合电容去离子（HCDI）系统的潜在阴极。rGO 和 rGO/Co3O4 复合材料的结构和形貌已经使用 XRD、FT-IR、TGA 和 SEM 进行了分析。表征证实了 rGO 片上 Co3O4 的均匀晶体生长，rGO 重量百分比为 9.4 (rGO/Co3O4-A) 和 25.2 (rGO/Co3O4-B)。循环伏安法研究表明，rGO/Co3O4-B 电极表现出高比电容（5 mV s-1 时为 210 F g-1）并具有氧化还原特性。本文还研究了初始浓度和电压对 rGO 和 rGO/Co3O4 复合材料的离子去除能力的影响。基于 rGO/Co3O4-B 的 HCDI 系统具有 18.63 mg g-1（250 mg L-1，1.6 V）的显着高离子去除能力，是基于纯 rGO 的 CDI 系统（6.45 mg g-1）的 2.8 倍）。此外，rGO/Co3O4 复合材料表现出优异的再生能力，表明其在高性能 CD​​I 系统中的潜在用途。