BOFFINS CLAIM THAT crumpled graphene balls could be used to make batteries lighter and capable of holding more lithium.
Scientists at the Northwestern University in the US claim that the new discovery could turn the technology industry “upside down”, with lithium-metal batteries holding the potential to power anything from mobile devices to connected cars.
Jiaxing Huang, a research fellow at the University, has been working on the project: “In current batteries, lithium is usually atomically distributed in another material such as graphite or silicon in the anode.
“But using an additional material ‘dilutes’ the battery’s performance. Lithium is already a metal, so why not use lithium by itself?”
The researchers have spent years trying to find the answer. However, the biggest challenge has been that when lithium charges and discharges, it can generate dendrites and filaments, with implications for safety and reliability.
Huang said: “At best, it leads to rapid degradation of the battery’s performance. At worst, it causes the battery to short or even catch fire.”
One solution involves bypassing the battery’s destructive dendrites by implementing a “porous scaffold”, although this causes different problems.
“As lithium deposits onto and then dissolves from the porous support as the battery cycles, its volume fluctuates significantly. This volume fluctuation induces stress that could break the porous support,” explained the researchers.
The scientists have come up with a solution “that makes batteries even lighter in weight and able to hold more lithium”. They’ve applied a scaffold “made from crumpled graphene balls”.
This method can stack with ease to form a porous scaffold, due to their paper ball-like shape, and can, according to the researchers, “prevent dendrite growth but can also survive the stress from the fluctuating volume of lithium”.
“One general philosophy for making something that can maintain high stress is to make it so strong that it’s unbreakable,” added Huang.
“Our strategy is based on an opposite idea. Instead of trying to make it unbreakable, our scaffold is made of loosely stacked particles that can readily restack.” µ
Source : Inquirer