Lithium metal batteries are the next generation of battery after the lithium-ion battery. They use a lithium anode and have higher energy density but have problems with dendritic growth, low efficiency, and low cycle life. To solve these problems, researchers developed a self-assembling monolayer that is electrochemically active so that it can decompose into its proper components and protect the surface of the lithium anode.
The battery is composed of the lithium anode, a lithium metal oxide cathode, and an electrolyte that also has lithium-ion conducting materials and the protective, thin film layer. Without this layer, the battery would tend to grow lithium crystal spikes if charged rapidly or under cold conditions. These lithium spikes eventually short out the battery, greatly decreasing the usefulness and cycle life.
The monolayer provides a solid electrolyte interface when charging and protects the lithium anode. The monolayer is deposited on a thin copper layer. When the battery charges, lithium hits the monolayer and decomposes to form a stable interfacial layer. Some lithium is deposited on the copper along with the remaining layer, and the decomposed portion of the original layer reforms on top of the lithium, protecting the lithium and preventing dendrites of lithium from forming.
The technology can increase the amount of storage capacity of the battery and can increase the number of times the battery can be charged; however, at this point, the battery can only be charged a few hundred times. The technology shows an ability to form a layer when needed and decompose and spontaneously reform so it will stay on the copper and also cover the surface of the lithium.