Although lithium-ion batteries are now the mainstream energy storage, the basic molecular and atomic science of charging and discharging them remains a mystery.
But Catalysis pointed out in Nature Catalysis that the research team has already made a breakthrough in identifying the chemical constituents of solid-electrolyte interphase (SEI) between electrodes and liquid electrolytes. Dusan Strmcnik, a chemical engineer at argonne national laboratory's materials science division (MSD), says this will help improve the team's ability to predict battery life, which is crucial for ev manufacturers.
For a long time scientists have dedicated to crack the lithium ion battery SEI, but only know when the battery will form the SEI formation, produced in the graphite electrode per mm thick film, the film can protect interface produces harmful reaction, and lithium ion moves back and forth between the electrode and the electrolyte, thus for lithium ion batteries, the performance good SEI as necessary. Strmcnik pointed out that battery efficiency and life span depend on SEI quality, and that if scientists can find out its chemical properties and independent composition rules, the SEI can improve battery efficiency.
So the argonne national laboratory and the university of Copenhagen in Denmark, Germany Munich university of technology, and the composition of the BMW group international research team, and successfully solve the lithium ion battery lithium fluoride SEI common chemicals (lithium fluoride).
Experimental and calculated results, points out that the battery produces in the process of hf (hydrogen fluoride) electrochemical reaction, the shift from the electrolyte to solid lithium fluoride and generate hydrogen gas, this kind of reaction is highly dependent on graphite and graphene and electrode materials such as metals, prove the importance of cell catalysts.
The team also developed a new method for detecting the concentration of hydrogen fluoride, which is a hazardous substance formed by moisture and lithium salts (LiPF6), and which plays a key role in SEI's future scientific research. Researcher Nenad Markovic said the research will be tested at BMW's battery research and development center in the future, and that the next step in the research is to plan to design new lithium-ion battery technology, which could open up a new path for lithium-ion batteries today.