本研究以兩步水熱合成法合成出鉬酸鎳銨Ammonium Nickel Molybdenum Oxide Hydroxide(ANM)與硫化鎳(NiS)附載在還原氧化石墨烯(rGO)上並應用於電化學超級電容器之電極材料。我們開創了合成鉬酸鎳銨(ANM)的新方法，透過兩步水熱合成出ANM-rGO，但由於ANM-rGO在3M KOH 電解液下只有127 F/g 的比電容值。為了改善其電容值，在第二步水熱反應中額外添加硫源，使部分的ANM轉換成硫化鎳，就合成出鉬酸鎳胺/硫化鎳/還原氧化石墨烯三元複合材料(ANM-NiS-rGO)。ANM-NiS-rGO作為超級電容器之正極材料，在3M KOH 電解液下操作電壓範圍為0-0.4V，在1 A/g電流密度下具有1346 F/g的高比電容值。在較大電流密度下也具有良好的循環穩定性，譬如在2 A/g下恆電流連續充放電1000次還可維持初始電容量的54 %。為了檢驗ANM-NiS-rGO電極材料在全電池裝置的電容性能，以ANM-NiS-rGO作為正極，還原氧化石墨烯作為負極電極，將兩電極組成非對稱式超級電容器。其操作電壓範圍為0－1.75 V，且在1 A/g下有高的比電容值(71 F/g)。在功率密度為 874.7 W/kg時, 可提供最大能量密度為30.19 Wh/kg。此外，該非對稱式超級電容器在2 A/g電流密度下恆電流充放電連續3000次循環後，維持初始電容量的60 %。 In this study, the composites consisting of ammonium nickel molybdenum oxide hydroxide(ANM)、nickel sulfides(NiS) and reduced graphene oxide (rGO) were synthesized using the two steps hydrothermal method and the as-synthesized composites were used as the electrode materials for supercapacitors. Although ANM-rGO can be synthesized through two step hydrothermal method, it shows the low specific capacitance of 126.65 F/g at 1 A/g in 3M KOH electrolyte. In order to improve its specific capacitance, the addition of sulfur source in the second step of the hydrothermal reaction can convert the partial AMN into nickel sulfide, thus obtaining ANM/NiS/rGO ternary composite (ANM-NiS-rGO). This ternary composite can be used as a cathode material for supercapacitors. Furthermore, ANM-NiS-rGO can be operated in the range from 0 to 0.45 V, and show the specific capacitance of 1346 F/g at 1 A/g. More importantly, the composite electrode shows a good cycling stability at a high current density. At a current density of 2 A/g, the device retains 54% of its initial capacitance after the consecutive 1000 galvanostatic charge-discharge cycles. To examine the capacitive performance of the composite electrode in a full-cell configuration, an asymmetric supercapacitor is fabricated by using the ANM-NiS-rGO composite as the cathode and rGO as the anode, respectively. The asymmetric supercapacitor can be operated reversibly from 0 to 1.75 V, and show a high specific capacitance of 70.97 F/g at 1 A/g, which delivers a maximum energy density of 30.19 Wh/kg at a power density of 874.7 W/kg. Furthermore, the asymmetric supercapacitor retains 60% of its initial capacitance after the consecutive 3000 cycles at a current density of 2 A/g.
