Some scientists believe that, to greatly improve the performance of current lithium-ion batteries, the introduction of lithium metal as an anode component may be a feasible method. And a "dream material" proposed by researchers at Washington State University (WSU) can replace the current anode material, thereby greatly promoting the development of lithium batteries. Facts have proved that if you want to integrate lithium batteries into the device safely, you still face some challenges.
(From: WSU, via New Atlas)
But now, scientists have proposed ways to overcome this obstacle. By adopting a new design, a layer of protection is added around the material to isolate the fire hazard.
It is reported that during the charging and discharging process, lithium ions can move back and forth between the two electrodes. At present, most anodes are made of a mixture of graphite and copper, but scientists have seen great room for improvement.
Min-Kyu Song of Washington State University said: "Pure lithium metal provides the highest energy density among solid materials. If used as an anode, it can extend the life of a lithium battery by two times and accommodate more energy."
Previously, efforts to integrate lithium metal into lithium-ion batteries have been plagued by safety issues. When lithium ions are transferred back and forth between the two poles of the battery, the return leads to the formation of so-called dendrites on the surface of the material.
These tentacle-like protrusions may cause the material to rupture and short-circuit, quickly lose charge, cause electric shock, or even fire. However, WSU's newly developed battery has overcome some of the safety issues surrounding pure lithium metal anodes.
A team of scientists led by Min-Kyu Song thought of the cathode of the battery made of a non-toxic chemical substance (selenium disulfide) with a porous structure.
At the same time, two additives were introduced into the electrolyte solution (a medium for lithium ions to move back and forth between the two poles), and it was found that this mixed material can form a protective layer on the surface of the lithium metal anode.
It is dense, conductive and strong, which can promote good charging stability while avoiding the formation of dangerous crystal dendrites. Subsequent tests show that the new battery can not only be recharged 500 times, but also maintain high efficiency.
Min-Kyu Song said: "This unique protective layer will hardly cause the morphological change of the lithium anode during the cycle, and effectively reduce the growth of lithium dendrites and harmful side reactions."
Finally, scientists are also working on other methods for introducing pure lithium metal anodes into batteries, including the use of solid electric (rather than liquid) electrolytes.
In recent years, such solid-state batteries have shown exciting potential. However, the WSU team's plan clearly has more practical commercial advantages.
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