Researchers at the University of California-Riverside’s Bourns College of Engineering are working to modify the size and shape of battery components as a means of achieving smaller, more powerful, and more energy-efficient batteries for electric vehicles.
“First, our goal was to make battery materials with a high power density—that is, to make them so that you could access power quickly and in large quantities,” David Kisailus, the project’s lead researcher, told SAE Magazines.
A team of researchers from Kisailus’s Biomimetics and Nanostructured Materials Lab are also looking to improve the energy density of batteries. "In this case," he said, "by making the particles smaller and thinner, we believe we can pack more material into a battery if we can not only fabricate these nanomaterials but also align them. If we can achieve this, it is possible to get a battery that can hold a charge 50% longer than current batteries.”
The research team’s preliminary work has focused on the cathode, in particular one of lithium-iron-phosphate (LiFePO4). The LiFePO4 benefit list includes relatively low toxicity as well as thermal and chemical stability. But the limitations—namely, poor electronic conductivity and relatively immobile lithium ions—correlate to large, bulky battery packs that take hours to charge.
To overcome these deficiencies, researchers used a solvothermal synthetic method in which reactants were placed in a container and heated under pressure to control particle growth. They used a mixture of solvents to control the size, shape, and crystallinity of the particles, and monitored how the LiFePO4 formed. They were then able to determine the relationship between those nanostructures and battery performance.
“We are using this bio-inspired materials processing to control cathode and anode particle sizes and shapes, which would significantly reduce charging times in batteries,” said Kisailus.
Further research work is expected to unfold on multiple fronts. For instance, the investigative team wants to produce ultra-thin carbon coatings “that make the battery materials more conductive without impeding lithium-ion transport—in other words, making them fast conductors,” Kisailus said.
Also being investigated are novel synthetic routes to tailor the performance of anodes by controlling their size and shape with the goal of shortening battery charging time.
The researchers are also looking at industrial applications, such as municipal energy storage, for batteries.
Whether for vehicles or industrial applications, "there are many aspects and issues with current battery technologies, and the need for intensive research towards this end is massive,” said Kisailus.
This University of California-Riverside research project, which started in October 2011, is sponsored by the Winston Chung Global Energy Center, which is named after Chinese battery inventor Winston Chung.