Novel three-dimensional carbon nanotube networks as high performance thermal interface materials

Abstract

Vertically aligned carbon nanotube (VA CNT) arrays are considered as promising thermal interface materials (TIMs) due to their superior out-of-plane thermal conductivities. However the air gaps between adjacent CNTs within the CNT array hinder the in-plane heat transfer, thus significantly degrading the thermal performance of VACNT-based TIMs. To improve the inter-tube in-plane thermal conduction within of VACNT arrays, we propose a novel three dimensional CNT (3D CNT) network structure, where the CNTs in a VACNT array are cross-linked by randomly-oriented secondary CNTs. Three different catalyst preparation methods for the secondary CNT growth are compared in terms of their ability to produce a dense network of secondary CNTs. Among the tested methods, the chemical impregnation method shows a denser 3D CNT network structure. The 3D CNT network grown using this method and is thus chosen for further thermal characterization via a framework especially developed for the evaluation of in-plane thermal properties of such devices. The temperature fields of the corresponding 3D CNT network under different heating powers are recorded using a 15 μm-resolution infrared thermal imaging system. The in-plane thermal conductivity is then derived from these fields using numerical fitting with a 3D heat diffusion model. We find that the in-plane thermal conductivity of the 3D CNT network is 5.40±0.92 W/mK, at least 30 times higher than the thermal conductivity of the primary VACNT array used to grow the 3D CNT network.

Thermal conductivity of carbon nanotube networks: a review

“…The third-harmonic method (3-x method) is commonly used in measurement of thermal properties of bulk materials and films [31][32][33][34][35][36][37][38][39], in which the sample is heated using alternating current with x frequency. A temperature variation with 2 x frequency was induced in the sample while heating, and a drop in voltage with 3 x frequency was recorded across the heater.…”

Two‐Dimensional SnSe2/CNTs Hybrid Nanostructures as Anode Materials for High‐Performance Lithium‐Ion Batteries

“…Doping or compounding of the two different materials can lead to ah ybrid electrode with good performance. [40][41][42] The special structureo fc arbon nanotubes makes them an excellente nergy storagem aterial for lithiumion batteries. [27][28][29][30][31] As aI V-VI layered material, and with the merits of natural abundance and low toxicity,S nSe 2 has demonstrated good prospects as an anode material for use in lithium-ionb atteries and solar cells.…”

“…[39] Carbon nanotubes (CNTs) are seamless, hollow "micropipes" made up of single or multi-layer graphite sheets wound aroundacentral axis at ac ertain helix angle, with each layer consistingo fahexagonal arrangement of sp 2 -hybridized carbon atoms. [40][41][42] The special structureo fc arbon nanotubes makes them an excellente nergy storagem aterial for lithiumion batteries. In addition, the cylindrical structure of carbon nanotubes does not collapse after repeatedc harge and discharge cycles, which can significantly enhance electrochemical performance, especially the cycle life of batteries.…”

3D Thermally Cross‐Linked Graphene Aerogel–Enhanced Silicone Rubber Elastomer as Thermal Interface Material

“…The TC of the composite increased from 0.16 to 0.26 W m −1 K −1 with the addition of 8 wt% of GNPs. Based on the previous works, it can be seen that graphene as a filler can improve the TC of TIMs effectively, nevertheless, the TC is still much lower than the theoretical value (according to the formula: κ TIM = ϕ matrix κ matrix + ϕ np κ np , where ϕ is the volume fraction and κ is the TC), which is caused by the interfaces between graphene and matrix.…”