BATTERIESBoosting Battery Research
Most Americans don’t leave home without at least one lithium battery-powered device, and someday, the house itself may have a battery backup. Scientists are working to make these large backup batteries less expensive, hold more energy and be less prone to bursting into flame.
Most Americans don’t leave home without at least one lithium battery-powered device, and someday, the house itself may have a battery backup.
Scientists at Sandia are working to make these large backup batteries less expensive, hold more energy and be less prone to bursting into flame. One way to tackle all three challenges is by changing up the battery chemistry with the addition of sulfur, according to Sandia battery expert Melissa Meyerson.
“One of the biggest benefits compared to what is on the market today is the energy density,” Melissa said. “Lithium and sulfur are two of the most energy-dense materials for batteries, and sulfur is incredibly cheap.”
A partnership between technical experts at Sandia and local entrepreneurs facilitated by DOE’s Boost program aims to get big, safe, stationary lithium-sulfur flow batteries to market faster.
The flow battery design allows for a physical separation of the portions of a household battery labeled with a minus and plus sign. This separation should make the battery safer and less likely to lose charge when just sitting idle, said Leo Small, a Sandia materials scientist who is also part of the collaboration.
“One goal is to make grid-scale batteries: really, really big batteries,” Leo said. “One of the objectives we were trying to go after by putting the lithium sulfur chemistry into a flow battery architecture was to physically separate the anode and the cathode to potentially make it safer when dealing with thousands or millions of kilowatt-hours of energy storage.”
One thousand kilowatt-hours are enough to power approximately 33 U.S. households for a day.
Building Better Battery Technology
The team’s largest technical hurdle was adapting lithium-sulfur chemistry into a flow battery design, Melissa said.
The current lab-scale battery, about three inches wide, consists of a solid lithium metal anode, representing the minus sign side of a household battery, and a liquid cathode, representing the plus sign side. When the battery provides electricity, the lithium metal becomes lithium ions. The other side of the battery comprises a complex cathode-organic electrolyte with lithium salt and sulfur bits mixed in, Melissa said. On that side, the lithium salt and sulfur become lithium sulfide when the battery provides electricity. Both sides of the battery contain other chemicals that help charging and discharging reactions take place. A pump moves around the electrolyte and these helper-chemicals to restore them to their active form.
