| Popis: |
New advances in synthesis of single wall carbon nanotubes (SWCNTs) allowed for the first time to produce multi-ton quantities of this unique material while significantly reducing its cost, opening up many commercial applications in energy storage. One of the applications is the use of SWCNTs as a conductive additive for high energy Li-ion batteries. It was found, that electrical properties of SWCNTs allow to reduce the amount of it in cathode and anode formulations to below 0.1% versus typical 2-5% of carbon black, maximizing the percentage of active materials and increasing the energy density of the Li-ion cells. Investigation of the electrode formulations revealed uniform distribution of SWCNT throughout the electrode structures, reinforcement of the electrode structure resulting in improved mechanical properties and electrochemical performance with both cathode and anode materials. In this presentation we will discuss the properties of commercially made SWCNTs and their comparison to MWCNTs and typical conductive carbons. Technical challenges facing application of SWCNTs in batteries include preparation of stable dispersions and formulation of electrodes with good electrical and mechanical properties. The results on various polymer dispersants will be presented along with ways of accommodating low concentration dispersions into the material mixing process and battery manufacturing. Test data was generated with LCO, LFP and NCM cathode materials and Si anode material will be discussed in detail with short term rate capability and long term cycle life and storage results. |
