WSU's Dream Material Brings Breakthrough to Lithium Battery Design

To significantly improve the current lithium battery performance, some scientists believe that the introduction of lithium metal as an anode component may be a feasible method. A "dream material" proposed by researchers at Washington State University (WSU) could replace the current negative electrode material, boosting the development of lithium batteries. As it turns out, wanting to integrate lithium batteries safely into the device still faces some challenges.

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 isolate fire hazards.

It is reported that in the process of charging and discharging, 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 significant room for improvement.

researchers at WSU image

Min-Kyu Song of WSU 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 battery and hold more energy.”

Previous efforts to integrate lithium metal into lithium-ion batteries have been plagued by safety issues. 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-like protrusions can cause the material to rupture and short, quickly lose its charge, trigger electric shocks, and even fires. However, WSU's newly developed batteries have 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 a battery made of a porous non-toxic chemical (selenium disulfide).

At the same time, two kinds of additives were introduced into the electrolyte solution (a medium for lithium ions to move back and forth between the poles), and it is found that this mixed material can form a protective layer on the surface of the lithium battery anode.

Washington State University research team image

It is dense, conductive and sturdy, which can promote 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 maintain high efficiency.

Min-Kyu Song said: "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."

Finally, scientists are working on other ways to introduce pure metal anodes into lithium battery, including using solid-state (rather than liquid) electrolytes. In recent years, such solid-state batteries have shown exciting potential. However, the WSU team's plan obviously has a more practical commercial advantage.

 

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