Ahmad Reyaz, Sohail Aamir, Yousuf Mahvesh, Majeed Asif, Mir Arshid, Aalim Malik, Shah M A
Department of Physics, National Institute of Technology Srinagar, Hazratbal, Srinagar 190006, (J&K), India.
Nanotechnology. 2023 Nov 20;35(6). doi: 10.1088/1361-6528/ad06d3.
Nickel-based oxides are selected for their inexpensive cost, well-defined redox activity, and flexibility in adjusting nanostructures via optimization of the synthesis process. This communique explores the field of energy storage for hydrothermally synthesized NiO/ZnO nanowires by analysing their capacitive behaviour. The p-type NiO was successfully built onto the well-ordered mesoporous n-type ZnO matrix, resulting in the formation of p-n heterojunction artefacts with porous nanowire architectures. NiO/ZnO nanowire-based electrodes exhibited much higher electrochemical characteristics than bare NiO nanowires. The heterojunction at the interface between the NiO and ZnO nanoparticles, their specific surface area, as well as their combined synergetic influence, are accountable for the high specific capacitance () of 1135 Fgat a scan rate of 5 mV s. NiO/ZnO nanowires show an 18% dip in initial capacitance even after 6000 cycles, indicating excellent capacitance retention and low resistance validated by electrochemical impedance spectroscopy. In addition, the specific capacitance, energy and power density of the solid state asymmetric capacitor that was manufactured by employing NiO/ZnO as the positive electrode and activated carbon as the negative electrode were found to be 87 Fg, 23 Whkgand 614 Wkg, respectively. The novel electrode based on NiO/ZnO demonstrates excellent electrochemical characteristics all of which point to its promising application in supercapacitor devices.
镍基氧化物因其成本低廉、氧化还原活性明确以及通过优化合成工艺调整纳米结构的灵活性而被选用。本公报通过分析水热合成的NiO/ZnO纳米线的电容行为来探索其储能领域。p型NiO成功构建在有序的介孔n型ZnO基质上，形成了具有多孔纳米线结构的p-n异质结产物。基于NiO/ZnO纳米线的电极表现出比裸NiO纳米线更高的电化学特性。NiO和ZnO纳米颗粒界面处的异质结、它们的比表面积以及它们的协同综合影响，是在5 mV s的扫描速率下1135 Fg的高比电容的原因。即使在6000次循环后，NiO/ZnO纳米线的初始电容也仅下降了18%，这表明其具有优异的电容保持率，并且通过电化学阻抗谱验证了其低电阻。此外，以NiO/ZnO为正极、活性炭为负极制造的固态非对称电容器的比电容、能量密度和功率密度分别为87 Fg、23 Whkg和614 Wkg。基于NiO/ZnO的新型电极表现出优异的电化学特性，所有这些都表明其在超级电容器器件中的应用前景广阔。
