
Scientists from the Korean Institute of advanced technology have found a promising way to protect the batteries with silicon anodes from degradation.
For this they used a molecular "couplers" from polyrotaxane molecules, which do not allow silicon particles to the anode to fall apart. Batteries with a silicon anode can store several times more energy in comparison with existing analogues. Scientists say they are already working on a possible implementation of the invention with a large Korean manufacturer of rechargeable batteries.
A study published in the journal Science, briefly about it reports the Verge.
Common lithium-ion batteries consist of a lithium cathode and a graphite anode. During charging, lithium ions move to the anode during discharging in the opposite direction. But a graphite anode is a promising alternative to silicon. It can store several times more energy, but this material has a drawback: during charging, it expands several-fold and crack. Because of this, the life of these batteries drops sharply after tens of cycles of charge-discharge, which is clearly insufficient for widespread application.
Korean scientists have found a way to keep the microparticles of silicon in the anode. To do this they attached to the anode grid of polyrotaxane molecules. They consist of molecules, strands and "threaded" on it, molecules of the rings. Some rings were connected with threads. Thus, the silicon surface was created molecular sieve, which allowed it to expand, but pulled it back and thus not allowed to disintegrate.
Comparison of conventional silicon-based anode and an anode made of new technology
Sunghun Choi et al. / Science, 2017
This prototype battery with such an anode efficiency hardly decreases after more than a hundred cycles of charge-discharge. Despite the rather complicated structure of the anode, the scientists hope that they will be able to Refine its production technology for widespread adoption. They claim that they are already in partnership with an unnamed "major Korean manufacturer of batteries".
Scientists are constantly working to improve batteries, in particular of the anodes. In 2016 the American scientists replaced the graphite anode, but not on silicon, and modified nanoparticles of the fiber of mushrooms. Another group of scientists in the same year, proposed to use as the anode material, pollen, and Indian scientists have proposed to make the anodes of soot from candles.
Source: N+1