Heterostructured Ni(OH)2–Co(OH)2 composites on 3D ordered Ni–Co nanoparticles fabricated on microchannel plates for advanced miniature supercapacitor

• Published in: Journal of alloys and compounds Vol. 589; pp. 364 - 371
• Main Authors: Li, Mai, Xu, Shaohui, Zhu, Yiping, Yang, Pingxiong, Wang, Lianwei, Chu, Paul K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-03-2014; Elsevier
• Subjects: Applied sciences; Electrochemical capacitors; Electrodeposition; Electronics; Exact sciences and technology; Materials; Nanoparticles; Ni–Co alloys; Ordered three-dimensional microchannel plates; Nanoparticles; Electrodeposition; Ordered three-dimensional microchannel plates; Ni–Co alloys; Electrochemical capacitors; Nanoparticle; Nickel Hydroxides; Nanostructure; Microminiaturization; Composite material; Electrochemical properties; Cobalt Hydroxides; Cobalt alloy; Reaction mechanism; Supercapacitor; Capacitance; Microstructure; Heterostructures; Nickel alloy; Ni-Co alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.11.230

•Electrochemical deposit heterostructured Ni(OH)2–Co(OH)2 composites uniformly on Si microchannel plates (MCP).•The microchannel is an ideal 3D substrate giving an aspect ratio of around 50.•The device performance change with the different Co(OH)2 doping proportion in Ni(OH)2.•The specific capacitance of 7.8Fcm−2 can achieved when Ni(OH)2 mixed with 10% Co(OH)2.•The impedance spectra insist that the device is excellent for micro power sources.
Silicon microchannel plates (Si-MCPs) coated with a layer of nickel cobalt alloy (NCA) constitute an excellent substrate for miniature supercapacitors. Nanoscale Ni(OH)2–Co(OH)2 composite particles serving as the active materials are electrodeposited on ordered three-dimensional (3D) NCA/Ni/Si-MCPs and the Ni(OH)2–Co(OH)2 composites have different structures depending on the amount of Co(OH)2 in Ni(OH)2. The nickel hydroxide synthesized from a water–acetone 0.1M Ni(NO3)2⋅6H2O solvent has a compact structure, but that from a 0.1M Ni(NO3)2⋅6H2O solvent containing 5% Co(NO3)2⋅6H2O is loosely packed with nanoparticles and that from a 0.1M Ni(NO3)2⋅6H2O solvent containing 10% Co(NO3)2⋅6H2O contains many nanoparticles. Addition of Co(NO3)2⋅6H2O results in a smooth morphology. The smooth structure is also observed from active materials produced in 20% and 30% Co(NO3)2⋅6H2O solvents. Five types of electrode materials are investigated from the perspective of electrochemical capacitors by conducting cyclic voltammogram, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy. In this experiment, the highest specific capacitance of 7.8Fcm−2 is achieved in the samples prepared in 10% Co(NO3)2⋅6H2O at a discharge current density of 20mAcm−2. It is much better than 1.46Fcm−2 observed from previous attempts and the materials have excellent capacity retention.