Carbon NanoTubes-based Conductive Additives for Lithium Ion Batteries

  

The lithium-ion battery is widely used in the fields of portable electronics to electric cars, due to their superior energy density over other rechargeable battery technologies and promising energy storage applications. The unique one-dimensional structure formed by the graphene layer makes carbon nanotube-based conductive additives possess excellent mechanical, electrical, and electrochemical properties and becomes a hot material in the research of lithium-ion battery. CNTs-based Conductive Additives for Lithium Ion Battery are a kind of composite having high electric conductivity containing high electric conductive carbon nanotubes and carbon black. The Carbon black particles help preventing carbon nanotubes dispersion from reagglomeration, exhibit synergetic effect with CNTs in Li-ion battery and enhance the conductivity of the composite electrodes. This product can be used in both anodes and cathodes of the Li-ion batteries and improve their electrochemical properties remarkably. When using our CNTC the capacity of battery does not decline with repeated cycling. More important, the product is very easy to be dispersed in Li-ion battery electrode, and can help to prevent the electrode materials from degradation caused by the expansion and contraction of electrode materials during charging and discharging.

In addition, CNTs have the capability to be assembled into free-standing electrodes (absent of any binder or current collector) as an active lithium ion storage material or as a physical support for ultra high capacity anode materials like silicon or germanium. The measured reversible lithium ion capacities for CNT-based anodes can exceed 1000 mAh g−1 depending on experimental factors, which is a 3× improvement over conventional graphite anodes.

The CNT-based composite electrodes can be fabricated by mechanical or chemical approaches. Owing to the large aspect ratio and the high electrical conductivity, CNTs at very low loading can lead to an efficient conductive network. The excellent mechanical strength suggests the great potential in forming a structure scaffold to accommodate nano-sized electrode materials. Dispersion of Carbon Nanotubes is known to be challenging due to the presence of bulk nanotubes which are normally highly entangled with each other. By adding grain electrode conductive additives to Carbon Nanotubes, the entangled Nanotubes are well separated. Furthermore, after adding Conductive Nanotubes Composite additive, the tap density of battery electrode coatings can be increased by 10%. Other progress may be achieved using open-ended structures and enriched chiral fractions of semiconducting or metallic chiralities that are potentially able to improve capacity and electrical transport in CNT-based lithium ion batteries.