New imaging technique that allows to observe the processes inside a lithium-ion battery.
Lithium-ion batteries are very widely used in small-scale and large-scale applications such as wireless IoT networks, electric vehicles, mobiles, laptops, uninterruptible power supplies, etc. These are rechargeable batteries in which lithium ions move from the negative electrode of the battery to the positive electrode through an electrolyte. In this way, the chemical energy converts into electrical energy. For charging, the afore-mentioned process reverses.
For optimizing the charging process and reducing the charging time, it is necessary to understand what exactly happens inside the lithium-batteries and how lithium ions flow in real-time as battery charges and discharges.
Researchers from the University of Cambridge have recently discovered a low-cost technique that allows them to observe the processes inside the battery. This technique helped them identify the speed-limiting processes in the li-ion batteries. If addressed correctly, the researchers believe that this study can enhance the charging process and allow us to charge our portable devices in as little as a few minutes.
To improve the lithium-ion battery charging process, researchers need to follow and understand the processes occurring in functioning materials under realistic conditions in real time. This is currently done by X-ray microscopy technique which is time consuming as well as expensive.
The team of researchers developed an optical microscopy technique called interferometric scattering microscopy to observe these processes at work. Using this technique, they were able to observe individual particles of lithium cobalt oxide (LCO) while charging and discharging by measuring the amount of scattered light.
The team discovered that there are different speed-limits for lithium-ion batteries depending on whether it is charging or discharging. During charging, the speed depends on how fast the lithium ions can pass through the particles of active material and when discharging, the speed depends on how fast the ions are inserted at the edges.
According to the researchers, if we can learn from what we observe with this technique, we can create new materials and mechanisms that would enable lithium-ion batteries to charge much faster. With this technique, safety of the li-ion batteries can also be improved. The amount of particles flowing through a cross section can be sampled to get information about what happens when batteries fail and how to prevent it.
“The technique is a quite general way of looking at ion dynamics in solid state materials, so you can use it on almost any type of battery material,” said Professor Clare Grey, from Cambridge’s Yusuf Hamied Department of Chemistry, who co-led the research.
Further information regarding the research can be found on the Nature article.