Researchers at the University of Illinois (Champaign, Illinois) are applying self-healing technology to lithium-ion batteries to make them more reliable. The group developed a battery that utilizes a silicon nanoparticle composite material on the negatively charged side and uses a novel way to hold the composite together—often a problem in batteries with silicon.
The negatively charged electrode, or anode, inside lithium-ion batteries are typically made of a graphite particle composite. These batteries work well, but they can take a long time to power up. Over time, the charge does not last as long. Past research found that anodes made from nano-size silicon particles are less likely to break down, but suffer from other problems.
“You go through the charge-discharge cycle once, twice, three times, and eventually you lose capacity because the silicon particles start to break away from the binder,” says Scott White, an engineering professor who helped lead the study.
To combat this problem, the group further refined the silicon anode by giving it the ability to fix itself on the fly. This self-healing happens through a reversible chemical bond at the interface between the silicon nanoparticles and polymer binder.
The researchers tested their new battery against one without the reversible chemical bonding and found that it retains 80% of its initial capacity, even after 400 cycles. It also has higher energy density, meaning it can store more electricity than a graphite-anode battery.
Future studies will examine how this technology can work with solid-state batteries.