Researchers from Stanford University have successfully created a lithium battery that self heals, thus, extending its capacity to hold electrons effectively for a longer time.
The biggest glitch in the world of technology today is the absence of longer lasting batteries. Your phone, your car battery and your watch only runs till the time your device battery is charged. How long the charge lasts depends on its capacity to hold on to electrons. Silicon is one material that effectively fulfills this requirement and is used in lithium-ion batteries. This material is capable of holding large amounts of energy, thus, lengthening the battery life. However, over time silicon loses this capability. This is because the process of charging them causes them to expand and then shrink again as the electrons are released. Over time, cracks develop in the silicon and it eventually can't store electrons anymore.
In an attempt to find a permanent solution to longer lasting batteries, researchers from Stanford University and the Department of Energy's (DOE) SLAC National Accelerator Laboratory developed a self-healing battery that is the first of its kind, reveals a press release.
"Self-healing is very important for the survival and long lifetimes of animals and plants," said Chao Wang, a postdoctoral researcher at Stanford and one of two principal authors of the paper. "We want to incorporate this feature into lithium ion batteries so they will have a long lifetime as well."
The team of researchers first developed a polymer coating for the electrodes that's based on research being used to develop artificial "skin" for robots. These polymers have weaker bonds than ordinary polymers, so that they break when the silicon electrode expands. However, the broken bonds of the polymer attract each other. So as the silicon shrinks, the polymer re-forms and pulls it back into shape.
"We found that silicon electrodes lasted 10 times longer when coated with the self-healing polymer, which repaired any cracks within just a few hours," said Zhenan Bao, a professor of chemical engineering at Stanford, whose group has been working on flexible electronic skin for use in robots, sensors, prosthetic limbs and other applications.
"Their capacity for storing energy is in the practical range now, but we would certainly like to push that," said Yi Cui, an associate professor at SLAC and Stanford who led the research with Bao. The electrodes worked for about 100 charge-discharge cycles without significantly losing their energy storage capacity.
"That's still quite a way from the goal of about 500 cycles for cell phones and 3,000 cycles for an electric vehicle," Cui said, "but the promise is there, and from all our data it looks like it's working."
The self-healing electrode, which is made from silicon micro-particles that are widely used in the semiconductor and solar cell industry, is the first solution that seems to offer a way to developing longer lasting batteries.
