Despite its cutthroat nature, the mobile device market can be quite predictable in terms of innovation, which is mostly restricted to just a handful of areas. What’s more, most of the innovation that we see is evolutionary. But to quote late Apple founder Steve Jobs, “Every once in a while a revolutionary product comes along that changes everything.” That’s exactly the kind of breakthrough researchers at Northwestern University seem to have stumbled upon.
In a breakthrough that could have implications for everything from cellphones to electric cars, a team of engineers at Northwestern University have managed to improve energy capacity and charge rate in lithium-ion batteries by a factor of 10.
“We have found a way to extend a new lithium-ion battery’s charge life by 10 times,” said Professor Harold H. Kung. “Even after 150 charges, which would be one year or more of operation, the battery is still five times more effective than lithium-ion batteries on the market today.”
This is how a press release issued by the University explains the breakthrough:
“In current rechargeable batteries, the anode — made of layer upon layer of carbon-based graphene sheets — can only accommodate one lithium atom for every six carbon atoms. To increase energy capacity, scientists have previously experimented with replacing the carbon with silicon, as silicon can accommodate much more lithium: four lithium atoms for every silicon atom. However, silicon expands and contracts dramatically in the charging process, causing fragmentation and losing its charge capacity rapidly.
Currently, the speed of a battery’s charge rate is hindered by the shape of the graphene sheets: they are extremely thin — just one carbon atom thick — but by comparison, very long. During the charging process, a lithium ion must travel all the way to the outer edges of the graphene sheet before entering and coming to rest between the sheets. And because it takes so long for lithium to travel to the middle of the graphene sheet, a sort of ionic traffic jam occurs around the edges of the material.
Now, Kung’s research team has combined two techniques to combat both these problems. First, to stabilize the silicon in order to maintain maximum charge capacity, they sandwiched clusters of silicon between the graphene sheets. This allowed for a greater number of lithium atoms in the electrode while utilizing the flexibility of graphene sheets to accommodate the volume changes of silicon during use.
Kung’s team also used a chemical oxidation process to create miniscule holes (10 to 20 nanometers) in the graphene sheets — termed “in-plane defects” — so the lithium ions would have a “shortcut” into the anode and be stored there by reaction with silicon. This reduced the time it takes the battery to recharge by up to 10 times.”
Original Post by Pulkit Chandna, Reposted Courtesy of Maximum PC – Covering everything from hi-end gaming PCs to tablets, peripherals and home theater rigs, Maximum PC’s print and Web editions stay one step ahead of the fast-changing world of everything computer and computing related. Whether its the latest on building your own desktop system, reviews of the latest laptops and accessories, or roundups of the games and software that make your machine go, Maximum PC brings it to you with news, reviews, and years of expertise. TechnoBuffalo is thrilled to bring you the best of Maximum PC right here on our own pages to keep you immersed in all things digital.