Ultrathin Metal Oxides Layer on A Carbon Nanotube Oriented Arrays Surface Formation Process Development and Study for Supercapacitors Electrode Specific Capacity Increasing

Sergei Aleksandrovich Gavrilov¹, Alexey Alexeevich Dronov¹, Evgeny Pavlovich Kitsyuk², Egor Aleksandrovich Lebedev ¹and Igor Makarovich Terashkevich¹

¹National Research University of Electronic Technology (MIET) 124498, Moscow, Zelenograd, Shokin Square, 1 ²Scientific Manufacturing Complex “Technological Centre” 124498, Moscow, Zelenograd, Shokin Square, 1  

Abstract: The study demonstrates the possibility of the increase of specific capacity of supercapacitors by means of the formation of ultrathin layers of metal oxides (Al₂O₃, TiO₂, NiO) on a surface of an electrode material, which is an oriented arrays of carbon nanotubes. The study discusses the possibility of the application of ultrathin insulating layers of Al₂O₃ formed by means of ALD method. Deposition of ultrathin oxide layers was carried out by means of successive ionic layer adsorption and reaction (SILAR) and atomic layer deposition (ALD) methods from a gas phase. The authors developed and studied the features of methodologies of conformal deposition of ultrathin layers of metal oxides on complex surface of CNT (carbon nanotubes) based electrode. The study revealed the relationship of the specific capacity of an electrode materials and the thickness of formed layers of metal oxides on its surface. In order to do that the authors prepared experimental specimens, which consisted of two current collectors, made from stainless steel; on the specimen of those collectors composite electrodes, which comprised a separator, made from porous polypropylene, and electrolyte, were synthesized. The specific capacity of a capacitor structure was calculated in the course of the analysis of experimental charge-discharge characteristics. The analysis of the results showed that presence of an ultrathin layer of a metal oxide on a surface of an electrode material based on CNT significantly increases the specific capacity of a structure; however, an optimal thickness of the layer must be specified depending on a material and a method of deposition case-by-case. Presence of an optimum value of thickness of an oxide layer is related to the fact that, from one point of view, the increase of the thickness of a deposited layer increases the influence of pseudocapacity; from another point of view, it can lead to the decrease of the effective area of an electrode surface due to filling of mezapores' space between CNT. It was observed that the optimal method for application of ultrathin oxide layers in mass-production condition is ALD method with implementation of equipment with group loading of slices.

Keywords: atomic layer deposition; SILAR; (transition) metal oxides; supercapacitor; carbon nanotubes; electrode material; nanocomposite; energy accumulation (storage)

[ HTML Full Text]

Back to TOC