• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.509-513
• /
• 2020

The performance of TiO₂ microcones/CNT composites as an anode material for lithium ion batteries was investigated. TiO₂ microcones/CNT composites were prepared by the polarization followed by electrophoretic deposition approaches on anodic TiO₂ microcones, which were composed of individual nanofragments resulting in a large surface area where lithium ion can be stored. Compared to pristine TiO₂ microcones, TiO₂ microcones/CNT composite electrodes showed higher areal capacity with a stable cyclability due to an enhanced electrical and lithium ion conductivity. Furthermore, TiO₂ microcones/CNT composite electrodes exhibited good cycle life characteristics and excellent rate retention under a high current density of up to 20 C.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.3
• /
• pp.187-192
• /
• 2014

In this article, we report the fabrication and characterization of $CNT/Co_3O_4$ nanocomposite for lithium ion batteries. We expected that the composition with CNT is effective method to compensate for the low electronic conductivity of $Co_3O_4$ and suppress the stress from phase transition of $Co_3O_4$ during cycling. $CNT/Co_3O_4$ nanocomposites were composed of nano-sized $Co_3O_4$ particles, which were homogeneously distributed on the surface of CNTs. The $CNT/Co_3O_4$ electrode presented higher capacity than commercial graphite, good rate capability and stable cyclic performance. This implies that the $CNT/Co_3O_4$ could be a promising anode material for lithium ion batteries.

• Composites Research
• /
• v.25 no.3
• /
• pp.70-75
• /
• 2012

Interfacial durability and electrical properties of CNT, ITO or xGnP coated PVDF nanocomposites were investigated for acoustic actuator applications. The xGnP coated PVDF nanocomposite exhibited better electrical conductivity than CNT and ITO case due to the unique electrical property of xGnP, and this nanocomposite also showed good sound characteristics. Interfacial adhesion durability between either neat CNT or plasma treated CNT and plasma treated PVDF were measured by static contact angle, surface energy, work of adhesion, and spreading coefficient tests. The optimum acoustic actuation performance of xGnP coated PVDF nanocomposite was measured using sound level meter with changing radius of curvature and coating conditions. As compared to CNT and ITO, the xGnP was known as more appropriate acoustic actuator due to the characteristic electrical property. It is the most appropriate condition when the radius of curvature is 15 degree. Although sound characteristics were different with various coating thicknesses, it is possible to manufacture transparent actuator with good sound quality.

• Composites Research
• /
• v.28 no.6
• /
• pp.348-355
• /
• 2015

NDT (Non Destructive Test) of the adhesive joints is very important because their strengths have greatly affected by the worker's skill and environmental condition. Recently, the electric impedance method in which 1-2 wt% CNT was dispersed in the adhesive and the electric resistance of the adhesive joint was measured was suggested for the defect detection of the adhesive joint. The uniform dispersion of CNT in the electric impedance method is very important to make a constant electric resistance of the adhesive joint and the accuracy of defect detection depends on the uniform dispersion. In this paper, the adhesive joints in which CNT was dispersed in the adhesive by the four dispersion methods were made and their electric resistance were measured. The pre-process and evaporation process of CNT using the ultrasonic method and agitation method was used and the effective dispersion method was suggested. Also, the criteria to evaluate the dispersivity was proposed.

• Korean Chemical Engineering Research
• /
• v.46 no.5
• /
• pp.898-902
• /
• 2008

Prepared are three types of composite supercapacitor electrode, such as electroactive polyaniline(PAN), PAN/multi-walled carbon nanotube(CNT), and $CNT/PAN/RuO_2$. Cyclic voltammetry was performed to investigate the supercapacitive properties of these electrodes in an electrolyte solution of 1.0M $H_2SO_4$. The $CNT/PAN/RuO_2$ electrode showed the highest specific capacitance at all scan rates(e.g., 441 and $392F\;g^{-1}$ at 100 and $1,000mV\;s^{-1}$, respectively). In cycle performance, however, the PAN/CNT electrode demonstrated the best capacitance retention (66%) at $10^4th$ cycle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.275-275
• /
• 2007

Two sorts of electrode composed of Sulpur/CNT/PVDF and Silver/CNT/PVDF were prepared by in situ chemical method and their electrochemical performance were evaluated by using cyclic voltammetry, impedance measurement and constant-current charge/discharge cycling technique. Also, composite electrodes were characterized by FE-SEM and BET. Raw materials such as CNT/Silver and CNT/Sulfur were mixed in ethanol, dried. These mixed materials were heated at 900 and $320^{\circ}C$ for 2hr, respectively in order to enhance contact among CNT electrodes. Electric double layer capacitor cells were fabricated using these mixed powder with polymer of PVDF. For the charging and discharging characteristics measured at scan rate of 1 mA/s, Supercapacitor of Sulphur-CNT-PVDF electrode showed a better performance than that of Ag-CNT-PVDF, which seems to be related with lower contact resistance of Sulphur-CNT-PVDF electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.265-265
• /
• 2009

전기이중층 커패시터 전극으로 사용하는 활성탄에 도전제로서 CNT와 super-p의 함량에 따른 이중층 커패시터의 특성을 연구하였다. CNT 함량이 4wt%까지는 도전제로서 CNT 함량이 증가할 수록 용량이 감소하는 반면 6wt%이상에서는 CNT 함량이 증가할 수록 단위 체적당 정전용량이 증가하였다. 충, 방전 특성과 직류 저항도 정전용량의 경향과 유사함을 보이고 있으며 이와 같은 결과는 비표면적이나 도전율에 의한 결과 보다는 분산성에 의한 결과로 예상된다. Super-p 10.5wt%, CNT 6.0wt%에서 단위 체적당 정전용량은 $22g/cm^3$, 직류저항 6.1[$\Omega$]의 전기이중층 커패시터 특성을 얻을 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.146-150
• /
• 2004

We researched carbon nanotube(CNT) cartridge as a CNT sample for the fabrication of nanotweezer which is composed of a couple of single CNT tip. Our CNT cartridge was made by dielectrophoretic methods, a kind of micromanipulation technique using electric field. Therein we intended to fabricate the CNT cartridge with just conventional function generators and a set of simple electrode. A knife edge and a flat metal electrode were employed as a couple of electrode, and these electrode pair faced each other with the gap. When the gap is filled with CNT suspension, we induced AC electric field into the gap. Then CNTs was attached on the sharp edge in knife edge by dielectrophoresis. This knife edge with attached CNTs is called as the CNT cartridge.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.7
• /
• pp.550-554
• /
• 2013

Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed ${\beta}$ phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned ${\beta}$ phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the ${\beta}$ phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.3
• /
• pp.245-249
• /
• 2011

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, indium tin oxide (ITO), etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.