In the future, when a day arrives that your touchscreen smartphone battery will last you for longer than a single day, one of the people who we would like to thank could be Jianyu Huang. The Hindustan Times offered a cryptic write-up about the U.S based Sandia National Labs researcher who has invented a battery thinner than human hair - or in today's record, the world's thinnest battery.
This lithium-based battery is so small in shape that it was baked inside a transmission electron microscope. Huang says that doing it this way helped them figure out how such micro-batteries worked and bettered their understanding of how batteries worked in general. As those microscopic electrodes put together have a chance for significant improvements over what we've got now, they could be used in hybrid cars, laptops and cell-phones. For further reading please click here
It's good to hear about those scientists working on improving battery technology, rather than just the chip-makers constantly working to budget power consumption. Because let's face it - we're doing a lot more on our mobile devices than we were a decade ago; be it shooting hi-def video or using cell-phones as GPS navigation systems. All these things require more power; and with most smartphones measuring in the range of just 9 to 12 mm thickness, I doubt how many would trade back that slimness for better battery life.
Because nanowire-based materials in lithium-ion batteries offer the potential for significant improvements in power and energy density over bulk electrodes the researchers wanted to gain an understanding of the fundamental mechanisms by which batteries work. They therefore formed the battery inside a transmission electron microscope (TEM) so they could study the charging and discharging of the battery in real time and at atomic scale resolution.
By following the progression of the lithium ions as they travel along the nanowire, the researchers found that during charging the tin oxide nanowire rod nearly doubles in length. This is far more than its diameter increases and could help avoid short circuits that may shorten battery life. This unexpected finding goes against the common belief of workers in the field that batteries swell across their diameter, not longitudinally.
“Manufacturers should take account of this elongation in their battery design,” Huang said. “These observations prove that nanowires can sustain large stress (>10 GPa) induced by lithiation without breaking, indicating that nanowires are very good candidates for battery electrodes,” he added.
Atomic-scale examination of the charging and discharging process of a single nanowire had not been possible before because the high vacuum in a TEM made it difficult to use a liquid electrolyte. Huang’s group overcame this problem by demonstrating that a low-vapor-pressure ionic liquid – essentially molten salt – could function in the vacuum environment.
This means that although the work was carried out using tin oxide nanowires, Huang says the experiments could be extended to other materials systems, either for cathode or anode studies.