A New Composite Material on the Base of Carbon Nanotubes and Boron Clusters B12 as the Base for High-Performance Supercapacitor Electrodes

Dmitry A Kolosov,Olga E Glukhova

doi:10.3390/c7010026

Dmitry A Kolosov, Olga E Glukhova

Open Access

https://doi.org/10.3390/c7010026

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Abstract

We explore the quantum capacitance, stability, and electronic properties of single-walled carbon nanotubes decorated with B12 icosahedral boron clusters by first-principle calculation methods implemented in the SIESTA code. After the optimization of the built supercells, the B12 clusters formed bonds with the walls of the carbon nanotubes and demonstrated metallic properties in all cases. The network of carbon nanotubes with its large area and branched surface is able to increase the capacity of the electric double-layer capacity, but the low quantum capacity of each nanotube in this network limits its application in supercapacitors. We found that the addition of boron clusters to both the outer and inner walls increased the quantum capacitance of carbon nanotubes. The calculation of the transmission function near the Fermi energy showed an increase in the conductivity of supercells. It was also found that an increase in the concentration of boron clusters in the structure led to a decrease in the heat of formation that positively affects the stability of supercells. The calculation of the specific charge density showed that with an increase in the boron concentration, the considered material demonstrated the properties of an asymmetric electrode.

Highlights

Supercapacitors (SC) are devices with high capacity, power density and long lifetime.They are designed for highly efficient electricity storage and occupy an intermediate position between dielectric capacitors and accumulators [1,2,3,4,5]
SC are called as electric double-layer capacitors (EDLC), since the charge accumulation occurs at the interface between the electrode and the electrolyte
These theoretical results are confirmed by experimental works [18,19], which show that modified carbon nanotubes (CNTs) have a much larger capacity in comparison to pure CNTs

Summary

Introduction

Supercapacitors (SC) are devices with high capacity, power density and long lifetime. A number of theoretical works demonstrate that an increase in the QC of carbon materials is possible by the adsorption of metal atoms and some nonmetals on their surface or by creating vacancy defects [15,16,17]. These theoretical results are confirmed by experimental works [18,19], which show that modified CNTs have a much larger capacity in comparison to pure CNTs. CNTs can be modified by the adsorption of various atoms and atomic clusters on their walls. We identify (I) the dependence of QC of the electrode material based on CNT/B12 on the mass concentration of boron, (II) the regularities of the charge transfer between CNT and B12 clusters, and (III) the regularities of quantum electron transport in CNT/B12 material

Materials and Methods

B12. The vector translation was directed along the

The supercells the boron-modified nanotubes

Electronic and Transport Properties

Conclusions