A systematic investigation of the composite electrode materials is vital in fabricating supercapacitors with high specific capacitance and good stability. The present work systematically studies the synergistic effects of Ag nanoparticles (AgNPs) on the electrochemical behaviour of rGO-based supercapacitor anode and CoO/rGO composite cathode. The CoO/(Ag/rGO) composite has been fabricated by hydrothermally growing CoO nanoparticles over the previously prepared Ag/rGO support in the 70:30 ratio. The electrochemical performance of fabricated electrodes was evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in 1 M KOH electrolyte. The Ag/rGO electrode having 15 - 20 % of AgNPs displays a specific capacitance of 553.6 F/g by CV (@10 mV/s) and 449.4 F/g by GCD (@0.35 A/g), which is 2.9 – 3.1 times higher than pristine rGO, when scanned in the range of – 1.0 V - 0.0 V (Vs. Ag/AgCl). The CoO/(Ag-20/rGO) composite electrode (in the ratio 70:30) possesses 244.9 F/g of specific capacitance (by GCD @3.8 A/g in the range of – 0.2 V - 0.5 V (Vs. Ag/AgCl)), which is 3.2 and 2.0 times higher than CoO and CoO/rGO respectively. The CoO, CoO/rGO and CoO/(Ag/rGO) samples retained 67 % (at 3.8 A/g), 91 % (@1.4 A/g), and 82 % (@1.4 A/g) of specific capacitance after 2000 cycles. The asymmetric supercapacitor device in rGO||CoO/Ag/rGO configuration shows an initial specific capacitance of 438.0 F/g, energy and power densities of 38.9 Whkg and 640 Wkg, respectively, at 2 A/g current density. The demonstrated boost in performance arises due to the presence of Ag nanoparticles leading to enhanced conductivity, catalyzing the pseudocapacitive reactions and preventing the graphene layers from aggregation by acting as spacers, spacers, thus making Ag/rGO and CoO/Ag/rGO as potential electrode materials for asymmetric supercapacitors.

中文翻译：

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Ag纳米颗粒在rGO和Co3O4基非对称超级电容器电极材料中的协同效应


对复合电极材料的系统研究对于制造具有高比电容和良好稳定性的超级电容器至关重要。本工作系统研究了银纳米颗粒（AgNPs）对rGO基超级电容器阳极和CoO/rGO复合阴极电化学行为的协同效应。 CoO/(Ag/rGO) 复合材料是通过在先前制备的 Ag/rGO 载体上以 70:30 的比例水热生长 CoO 纳米颗粒而制成的。在 1 M KOH 电解质中通过循环伏安法 (CV) 和恒电流充放电 (GCD) 评估制造的电极的电化学性能。含有 15 - 20% AgNP 的 Ag/rGO 电极的比电容为 553.6 F/g（CV（@10 mV/s））和 449.4 F/g（GCD（@0.35 A/g）），即 2.9 - 3.1在 – 1.0 V - 0.0 V (Vs. Ag/AgCl) 范围内扫描时，比原始 rGO 高出数倍。 CoO/(Ag-20/rGO) 复合电极（比例为 70:30）具有 244.9 F/g 的比电容（GCD @3.8 A/g，范围为 – 0.2 V - 0.5 V（Vs. Ag）） /AgCl))，分别比 CoO 和 CoO/rGO 高 3.2 和 2.0 倍。 CoO、CoO/rGO 和 CoO/(Ag/rGO) 样品在 3.8 A/g 条件下保留了 67% (@1.4 A/g)、91% (@1.4 A/g) 和 82% (@1.4 A/g) 的比电容。 2000 次循环。 rGO||CoO/Ag/rGO 配置的不对称超级电容器器件在 2 A/g 电流密度下的初始比电容为 438.0 F/g，能量和功率密度分别为 38.9 Whkg 和 640 Wkg。 由于Ag纳米粒子的存在导致导电性增强，催化赝电容反应并通过充当间隔物防止石墨烯层聚集，从而使Ag/rGO和CoO/Ag/rGO成为潜在的电极，因此性能得到了提升非对称超级电容器材料。