Some scientists believe that the introduction of lithium metal as an anode component may be a viable way to significantly improve the performance of current lithium-ion batteries. Researchers at Washington State University (WSU) have come up with a “dream material” that could replace the current negative material, boosting the development of lithium batteries. It turns out that there are still tests to be faced with the safe integration of lithium batteries into the device.
(From: WSU, via New Atlas)
But now, scientists have come up with ways to overcome this obstacle. By adopting a new design, a layer of protection is added around the material to protect against fire hazards.
It is reported that in the process of charging and discharging, lithium ions can move back and forth between the two electrodes. Most of the current anodes are made from a mixture of graphite and copper, but scientists see significant room for improvement.
Min-Kyu Song, of Washington State University, said: “Pure lithium metal provides the highest energy density in solid materials, and if used as an anode, it can double the life of lithium batteries and hold more energy.”
Previous efforts to integrate lithium-ion metal into lithium-ion batteries have been plagued by safety concerns. When lithium ions pass back and forth between the cells of the battery, the back causes the formation of so-called branches on the surface of the material.
These tentacle-shaped protrusions can cause materials to break short, quickly lose charge, trigger electric shocks and even fires. However, WSU’s newly developed batteries have overcome some of the safety concerns surrounding pure lithium metal anodes.
A team of scientists led by Min-Kyu Song came up with the cathode of a battery made from a porous non-toxic chemical, selenium disulfisulfied.
At the same time, two additives are introduced into the electrolyte solution (the medium for lithium ions to move back and forth between the poles), and it is found that this mixture can form a protective layer on the surface of the lithium metal anode.
It is dense, conductive and robust, promoting good charging stability while avoiding the formation of dangerous branches. Subsequent tests have shown that the new battery can not only be recharged 500 times, but also remain sveable.
“This unique protective layer, during the cycle, rarely causes a change in the morphological form of lithium anodes and effectively reduces the growth of lithium crystals and harmful side-reactions,” says Min-Kyu Song.
Finally, scientists are working on other methods of introducing pure lithium-metal anodes into batteries, including using solid-state electricity instead of liquid electrolytes.
In recent years, these solid-state batteries have shown exciting potential. However, the WSU team’s approach clearly has a more practical commercial advantage.