Scientists discover new way to make high-energy, low-cost and long-life batteries

The journey from lab discovery to practical application can be long and challenging. Take lithium-sulfur batteries, for example. While lithium-sulfur batteries offer significant advantages over existing lithium-ion batteries for automobiles, they have not made substantial progress in the marketplace, despite years of rigorous development.

Thanks to the efforts of scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory, that may change in the future.best lithium ion battery machine company Over the past decade, they have made several key discoveries in lithium-sulfur batteries. Their latest discovery, published in the journal Nature, unravels a previously unknown reaction mechanism and addresses the major shortcoming of the battery's extremely short lifespan.

Lithium-sulfur batteries have three significant advantages over current lithium-ion batteries. First, lithium-sulfur batteries can store two to three times as much energy in a given volume, thus extending the range of a car. Second, they are economically viable due to their abundance and affordability, as they are less expensive. Finally, these batteries do not rely on key resources such as cobalt and nickel,equipment for lithium battery assembly which may be in short supply in the future.

Lithium-sulfur batteries have different reaction paths from lithium polysulfide to lithium sulfide, and sulfur anodes with and without catalysts.

Despite these advantages, a successful transition from laboratory to commercial viability is difficult. Laboratory batteries have shown good results, but when scaled up to commercial scale, their performance declines rapidly with repeated charging and discharging.

The root cause of the performance degradation is the dissolution of sulfur from the cathode during discharge to form soluble lithium polysulfide. This problem is further exacerbated by the flow of these compounds into the lithium metal negative electrode (anode) during charging. As a result, the loss of sulfur from the anode and changes in the composition of the negative electrode severely affect the performance of the battery during cycling.

In a recent early education study, Argonne scientists conducted development designed as a catalytic material that can be catalyzed to radically improve the solution to the sulfur loss problem by adding a small amount of this material to the sulfur cathode. While our catalyst of this kind has shown promise in both laboratory and commercial batteries, the incentives for it to work at the atomic level have remained a mystery until now.

The team's latest study reveals this mechanism. In the absence of a catalyst, lithium polysulfide forms on the surface of the cathode and undergoes a series of reactions that ultimately convert the cathode to lithium sulfide.

"However, the presence of a small amount of catalyst in the cathode makes a big difference," and the ensuing reaction path is quite different, with no intermediate reaction steps. "

The key is the formation of dense nanoscale lithium polysulfide bubbles on the surface of the cathode, which cannot be formed without a catalyst. Lithium polysulfide rapidly diffuses throughout the cathode structure during discharge and transforms into lithium sulfide composed of nanocrystals. The process prevents sulfur loss and performance degradation in commercial-sized batteries.

In uncovering the black box of the reaction mechanism, the scientists used state-of-the-art characterization techniques. The structure of the catalyst was analyzed using an intense synchrotron X-ray beam from the Advanced Photon Source 20-BM at the DOE Office of Science User Facility. The results show that the catalyst plays a crucial role in the reaction pathway. The structure of the catalyst affects the shape and composition of the final and intermediate products after discharge. In the case of using catalyst, nanocrystalline lithium sulfide is formed after complete discharge. Without a catalyst, a micron-sized rod-like structure is formed.

Another important piece of information technology developed at Xiamen University enabled the research through the team to visualize the electrode-electrolyte interface on a nanoscale while testing battery management efforts. This newly invented technological development helps to combine nanoscale variations with theoretical links to the behavior of working batteries.

"Based on this exciting discovery, we will conduct more research to design better sulfur cathodes. Whether this mechanism is applicable to other next-generation batteries, such as sodium-sulfur batteries, is also worth exploring."

With this latest breakthrough by the team, the future of lithium-sulfur batteries seems brighter, offering a more sustainable and environmentally friendly solution for the transportation industry.

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