New, lighter batteries are under development for soldiers now, in-house, at the Army Research Laboratory.
Chemists at the lab do materials research on lithium ion batteries and other advanced battery chemistry in an effort to support the warfighter.
“We help to develop new battery materials that are lighter and last longer for the soldier, so he doesn’t have to carry so many batteries,” said Cynthia Lundgren, a chemist and Chief of the Electrochemistry Branch of the Power and Energy Division in the Sensors and Electron Devices Directorate.
Army chemist, Jan Allen, demonstrates how to build a “button cell,” the type of battery used in a watch, at the Army Research Laboratory. (Photo by Gary Sheftick/Released)
To create a better battery, Lundgren and her team experiment with small “button cells,” such as what one might find in a watch. A cell consists of two electrodes: an anode, which is the side marked with a “minus” sign; and a metal oxide or phosphate cathode, which bears the plus sign.
Between these two electrodes is a liquid electrolyte soaked separator that facilitates the transfer of lithium ions to transfer charge. One or more of these cells is used to construct a battery pack.
The team tinkers with the different materials that make up both the cathode and the anode. They also tinker with the chemistry of the electrolyte of the battery. Lundgren said that one way to make a battery lighter is to use electrodes that increase its cell voltage.
“If we could raise the voltage of a single cell — energy density is a direct function of the voltage — we could make the battery lighter,” she said. “The problem is, as you go up in voltage, the electrode becomes much more energetic, and so it reacts with the electrolyte.”
The reaction of electrodes with the electrolyte is one of the key problems Lundgren and her team have proven successful at tackling.
Emily Wikner, an Army Research Laboratory intern (left), assists Army Research Laboratory scientist Arthur Cresce, in the Electrochemistry Branch. Cresce is the co-inventor of an electrolyte additive with the potential to increase lithium battery energy density by 30 percent. (Photo by Conrad Johnson, RDECOM Public Affairs/Released)
“The electrodes are very corrosive, and they react with the electrolytes,” said Von Cresce, a chemist at the lab. “So what ends up happening as you cycle the battery back and forth is that the electrolytes are degraded — For more information read the original article here.