Battery life is the bane of cell phones, laptops and electric cars. A new Lithium-ion battery has been designed to heal itself, increasing its life span and decreasing the number of dead batteries in the land fill.
Although batteries are rechargeable, they eventually break down from wear and tear. For example, the anode, the battery’s negatively charged terminal swells and shrinks as it charges and discharges. This eventually causes cracks which interfere with the current flow and kills the battery. Worse yet, the battery can go down in flames.
You’ll remember the flack over, and recall of, Dell and HP laptops that self destructed. Scott White, Ph.D., a materials engineer at the University of Illinois at Urbana-Champaign has embedded tiny microspheres, seen in the photo, inside the graphite of an anode. The spheres contain liquid indium gallium arsenide. When the battery cracks, the spheres break. The damage is healed as the liquid seeps out and fills the cracks, restoring the flow of electricity.
Professor White’s lab directs their research toward the creation of new materials systems that exhibit autonomy - the ability to achieve adaptation and response in an independent and automatic fashion. A team is developing self-generating structural materials for autonomic damage control in polymeric structures such as circuit boards, in addition to keeping batteries behaving properly.
To counteract the potential fire hazard related to the battery, White embedded small microspheres of solid polyethylene in various components of the battery. When the inside temperature goes above 105 degrees Celsius, the spheres melt to form an insulating material shutting off the flow of electricity, essentially robbing the potential fire of fuel.
As fuel prices go up, electric cars are becoming more common place on our roads. Battery safety, efficiency and life span will become a major consideration. Such advancements in lithium-ion batteries will pave the way for a successful transition from gasoline. Not to mention reducing the frustration everyone experiences with cell phones and laptops going dead at the most inconvenient times.