In Korea, there were more than 100,000 newly registered electric vehicles (EVs) in just one year. The only other nation that has comparable numbers is Norway. Anode materials are the key components that govern the battery life and charging efficiency of currently popular EVs. The domestic battery industry in Korea is dedicated to developing ground-breaking techniques for boosting battery capacity through the use of new technologies or different anode materials. But what if we eliminate anode materials entirely?
Anode-free lithium batteries with a long battery life on a single charge have been created by a POSTECH research team led by Professor Soojin Park and PhD candidate Sungjin Cho (Department of Chemistry) in collaboration with Professor Dong-Hwa Seo and Dr. Dong Yeon Kim (School of Energy and Chemical Engineering) at Ulsan Institute of Science and Technology (UNIST).
The volumetric energy density of the newly created anode-free battery is 977Wh/L, which is 40% more than that of conventional batteries (700Wh/L). This indicates that a single charge will power the battery for 630 kilometers.
During repeated charging and discharging, lithium ions flow to and from the electrode, changing the structure of anode materials in batteries. For this reason, the battery’s capacity depletes over time. It was believed that the energy density, which determines the battery capacity, would increase if charging and discharging could be accomplished solely with a bare anode current collector devoid of anode materials. The anode volume swells significantly, which shortens the battery life and is a serious flaw in this method. It grew because the anode lacked a stable place to store lithium.
By incorporating an ion conductive substrate, the research team was able to develop an anode-free battery in a typical carbonate-based liquid electrolyte. The substrate helps to limit the anode’s bulk expansion and protects it by forming a layer over it.
According to the study, the battery was able to maintain a high capacity of 4.2mAh cm-2 and a high current density of 2.1 mA cm-2 for an extended period of time in a liquid electrolyte based on carbonates. Substrates’ ability to store lithium has also been demonstrated, both theoretically and experimentally.
The fact that the team successfully demonstrated the solid-state half-cells using an argyrodite-based sulfide-based solid electrolyte is also grabbing attention. Because it can keep its high capacity for longer, it is expected that this battery will speed up the process of making non-explosive batteries available to the public.
The study that was just published in Advanced Functional Materials was paid for by the Alchemist project.
