Now, a new study by researchers at Stanford University points a way forward for building better, safer lithium-metal batteries. The research was recently published in the Journal of the Electrochemical Society.

Longer life lithium battery

 Li-metal batteries store more energy, charge faster, and are lighter than lithium-ion batteries.

 But so far, the commercial use of rechargeable lithium metal batteries has been limited.

 A major reason is the formation of "dendrites" -- thin, metal-like tree-like structures that grow as lithium metal accumulates on the electrodes inside the battery. These dendrites can degrade battery performance and eventually lead to failure and, in some cases, fire.

 Researchers at Stanford University tackle the problem of dendrites theoretically. They developed a mathematical model that combines the physical and chemical problems involved in "dendritic" formation.

 This model provides an insight that exchanging certain properties in a new electrolyte (the medium in which lithium ions move between two electrodes within a battery) can Slows down or even completely stops the growth of dendrites.

 "Our purpose is to serve the design of longer-life lithium metal batteries." said Weiyu Li, lead author of the study and a doctoral student in energy engineering at Stanford University. " Our mathematical framework explains key chemical and physical processes in lithium metal batteries."

 "This study provides some specific details about the conditions under which dendrites form, as well as potential pathways to inhibit their growth." Co-corresponding author of the report, Stanford University Earth, said Hamdi Tchelepi, a professor in the School of Energy and Environmental Sciences.

Prevents dendrite formation

Experimenters have long struggled to understand what causes dendrites to form. But lab work is labor-intensive, making it difficult to interpret the findings. To this end, the researchers developed a mathematical representation of the battery's internal electric field and the transport of lithium ions through the electrolyte material, as well as other related mechanisms.

This way, with research results in hand, experimenters can focus on physically sound material and architectural combinations. "Hopefully, other researchers can use our research to design devices with the right properties and reduce the scope for trial and error and experimental variation they have to do in the lab," Tchelepi said.

Specifically, the new strategies for electrolyte design called for by this research include understanding the anisotropy of materials, which means they exhibit different properties in different directions. Wood is a typical anisotropic material, and its grain is very directional, and many times you can see the lines of the wood, not the grain.

In the case of anisotropic electrolytes, these materials can fine-tune the complex interplay between ion transport and interfacial chemistry, preventing dendrite formation. The researchers note that some liquid crystals and gels exhibit these desirable properties.

Another approach identified in the study focused on battery separators—a thin film that prevents electrodes from touching and shorting across the battery's ends. They say it is possible to engineer new separators with porous features that allow lithium ions to pass back and forth in the electrolyte in an anisotropic manner.

Build a "digital avatar"

The team looks forward to seeing other researchers continue to work on the "clues" they give. Next steps include making devices that rely on new electrolyte formulations and battery architectures, testing which might prove to be efficient, scalable and economical.

"In general, there is a lot of research to be done in terms of material design and experimental validation of complex battery systems," said study co-corresponding author Daniel Tartakovsky, professor of energy engineering at Stanford University. .

Based on these latest findings, Tartakovsky and colleagues are building a virtual representation of a full-fledged lithium metal battery system (DABS) -- dubbed a "digital avatar."

"This research is a key component of DABS, and our lab is developing a full-scale 'digital avatar' or replica of a lithium metal battery," Tartakovsky said. "With DABS, we will continue to improve the technical level of these promising energy storage devices." (Source: China Science News Feng Lifei)