From pv magazine Global.
Among the many pathways to improving on today’s energy storage technologies, the addition of conductive ‘filler’ materials to electrodes promises better rate capability, conductivity and overall battery performance.
“Although a variety of conductive fillers have been extensively developed,” explain scientists led by the University of Texas at Austin (UTA), “the understanding of how the geometry and dimensionality of these fillers affect the electrode conductivity, architecture, and ultimately the electrochemical performance in high-energy storage systems, is still insufficient.”
The group conducted experiments with three different conductive carbon materials, to determine which offered the best performance. Varying amounts of single-walled carbon nanotubes, graphene nanosheets and ‘Super P’ – a type of carbon black particle already commonly used as a conductive filler in lithium-ion batteries – were added to a nickel-cobalt-manganese (NCM) cathode.
These cathodes were then measured using various spectroscopic and electrochemical characterisation techniques. Full results are published in the paper Unveiling the dimensionality effect of conductive fillers in thick battery electrodes for high-energy storage systems, published in Applied Physics Reviews.
Carbon nanotubes
Single-walled carbon nanotubes (SWCNTs) were shown to be the best performing additive. The group observed that the nanotubes formed a conductive coating around the NCM particles, and also formed interconnected networks between the NCM particles. Graphene nanosheets had a similar effect but formed less uniform structures.
The best of the SWCNT electrodes showed a capacity of 142 milliamp-hours per gram (mAh/g) at a charge rate of 0.2 C, falling to 101 mAh/g when the rate increased to 2 C. The group also found that as little as 0.16% by weight of SWCNTs was enough to ensure good conductivity. “When an electrically conductive filler is added to an insulating matrix,” explains UTA’s Guihua Yu, “significant increases in conductivity will occur once the first conducting pathway through the composite is formed.”
The group says its findings suggest that integration of SWCNTs in this way could facilitate better ion and charge transfers, leading to better-performing batteries especially at high discharge rates. And overall, the improved understanding of conductive filler behaviour could open new doors in the design of high energy/power density electrodes.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
26 comments
By submitting this form you agree to pv magazine using your data for the purposes of publishing your comment.
Your personal data will only be disclosed or otherwise transmitted to third parties for the purposes of spam filtering or if this is necessary for technical maintenance of the website. Any other transfer to third parties will not take place unless this is justified on the basis of applicable data protection regulations or if pv magazine is legally obliged to do so.
You may revoke this consent at any time with effect for the future, in which case your personal data will be deleted immediately. Otherwise, your data will be deleted if pv magazine has processed your request or the purpose of data storage is fulfilled.
Further information on data privacy can be found in our Data Protection Policy.