Nickel metal hydride batteries and lead-acid batteries, two types of aqueous batteries, are attractive for many applications due to their safety, low cost, high specific power, and flexible cell designs. They are used in hybrid and all-electric vehicles, consumer electronics, and telecommunications. Much progress has been made on some battery components (anodes, cathodes, and electrolytes) with a focus on increasing energy density and performance. However, current collectors, usually a metal grid or sheet, account for a significant amount of the weight and cost of batteries and play a critical role in performance, but have had little development. The current collectors commonly used today are heavy, expensive, bulky, and prone to corrosion under prolonged use. Next-generation current collectors could improve corrosion resistance and battery performance while decreasing weight and cost.
Project Innovation + Advantages:
The University of Maryland (UMD) will develop a new type of current collector using a film that is composed of functionalized few-walled carbon nanotubes (FWNTs) and polymers. The team seeks to develop a thin, low-cost current collector that displays high conductivity, excellent mechanical strength, flexibility, and manufacturing scalability. Carbon nanotubes have high conductivity, but in their pure state lack the needed mechanical strength. The FWNT concept will "functionalize" or bolster the outer walls by integrating polymers to increase the mechanical strength. This will give the product the dual benefits of direct tube-on-tube contact for fast recharging and increased mechanical strength and stability from the polymers. Replacement of metal mesh by FWNT-polymer film will not only address current collector corrosion concerns, but will also offer increased energy density due to the substantially lighter weight of these carbon-based materials compared to traditional metallic current collectors.