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EETE APR 2014

Sticky composites make safer lithium-ion batteries By Paul Buckley Researchers at the University of Delaware have shown that fragmented carbon nanotube films can serve as adhesive conductors in lithium-ion batteries. Electrodes in lithium-ion batteries typically comprise three components - active materials, conductive additives, and binders - but new research by a team of researchers at the University of Delaware has discovered a ‘sticky’ conductive material that may eliminate the need for binders. “The problem with the current technology is that the binders impair the electrochemical performance of the battery because of their insulating properties,” explained Bingqing Wei, professor of mechanical engineering. “Furthermore, the organic solvents used to mix the binders and conductive materials together not only add to the expense of the final product, but also are toxic to humans.” Wei and doctoral student Zeyuan Cao discovered that fragmented carbon nanotube macrofilms (FCNT) can serve as adhesive conductors, combining two functions in one material. FCNTs are web-like meshes with ‘tentacles’ that are coupled with active lithium-based cathode and anode materials. They are then assembled using simple ultrasound processing. The process employs no organic solvents. “We’ve found that the adhesive FCNT conductors actually have higher adhesion strength than PVDF, the binder traditionally used in lithium-ion battery manufacturing,” said Wei. “We’ve also demonstrated that these composite electrodes exhibit higher electrical conductivity than traditional materials, and we’ve achieved these benefits in a low-cost green fabrication process that replaces toxic organic solvents with just water and alcohol.” “There is a wide market for lithium-ion batteries and we see great potential for the use of this technology in vehicle applications, where quick charging and discharging are required.” The approach strategy could also be employed for electrode preparation for other energy storage devices such as electrochemical capacitors. The research is reported in ACS Nano, a specialty publication of the American Chemical Society. PSA, IBM jointly develop customized driver services By Christoph Hammerschmidt French carmaker PSA Peugeot Citroen announced it will offer connected services for the drivers of its vehicles - services that search and analyse huge amounts of data generated by connected vehicles and other sources. To identify useful information in the Exabytes of data, the company taps IBMs expertise in Big Data and Analytics. Both companies jointly develop techniques and solutions to acquire, integrate, store and analyse the data streams from connected vehicles but also from smartphones in these cars, traffic control system and other traffic data sources. The goal is devising individual information services to drivers which can be accessed through a variety of channels like Internet or smartphone. Today, the use of mobile devices is endemic - the growing popularity of smartphones does not only help people to stay connected, these devices also generate vast amounts of data themselves - data that are already used for dynamic traffic prediction (‘Floating Phone Data’ and ‘Floating Vehicle Data’). But there’s more in it, believe PSA Peugeot Citroën and IBM. The challenge for car manufacturers is to integrate value brought by processing and analysing real-time data from the connected vehicle. PSA and IBM collaborate to integrate these data from cars as well from other trafficrelated data and analyse it in real-time. PSA plans to combine its expertise in the auto industry with IBM’s Big Data & Analytics and MobileFirst to offer a range of Connected Services. An example could be more precise local weather forecasts generated by the data imput from the cars: Onboard temperature sensors, lights and windscreen wiper status will be fed into the system; as soon as in a certain area many vehicles turn on their wipers, the system will issue a precipitation warning. Many other services are imaginable, said IBM’s Global Automotive Industry manager Dirk Wollschläger. 20 Electronic Engineering Times Europe April 2014 www.electronics-eetimes.com


EETE APR 2014
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