Lithium-ion batteries are ideal for powering rechargeable electronics. This is because they can store a lot of energy and have extended lifespans. However, when temperatures drop below freezing, these energy sources' electrical effectiveness suffers, and in extreme cases, they may fail to transfer any charge. The problem arises as the anodes in the batteries become sluggish, storing less charge and discharging energy more quickly. But since cell phones must be recharged regularly when temperatures drop below freezing, and electric cars have lower driving ranges, this results in a huge problem.
Researchers, in a new study, replaced the conventional graphite anode in a lithium-ion battery. They changed it with a lumpy carbon-based material that maintains its rechargeable storage capacity down to -31°F (-35°C). The innovation could immensely benefit the Lithium Ion Battery Market as it may help overcome the problem and improve electrical performance in the extreme cold.
The team intended to improve the anode's charge transfer mechanism by changing the carbon-based material's surface structure.
The researchers heated the ZIF-67 (Cobalt-Containing Zeolite Imidazolate) framework to high temperatures. It helped them create the novel material. The rough surfaces of the newly created 12-sided carbon nanospheres demonstrated remarkable electrical charge transport capabilities.
The group then took the material through its paces as an anode. It was present within a coin-shaped battery with lithium metal as the cathode. The anode displayed steady charging and discharging at temperatures ranging from 77 degrees Fahrenheit to -4 degrees Fahrenheit. It also maintained 85.9% of its room temperature energy storage capacity, slightly below freezing.
The study found that lithium-ion batteries constructed using different carbon-based anodes, such as graphite and carbon nanotubes, held no charge at freezing temperatures. However, the anode built with rough nanospheres was still rechargeable after the researchers decreased the air temperature to -31 F. Upon discharge, it released nearly 100 per cent of the charge put into the battery.
At last, researchers added, incorporating the rough nanosphere material inside batteries could allow these energy sources to be used at extremely low temperatures.