{"id":3925,"date":"2022-03-24T22:00:00","date_gmt":"2022-03-24T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=3925"},"modified":"2022-03-09T08:59:20","modified_gmt":"2022-03-09T08:59:20","slug":"gamma-sulfur-may-hold-the-key-to-future-lithium-sulfur-batteries","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/gamma-sulfur-may-hold-the-key-to-future-lithium-sulfur-batteries\/","title":{"rendered":"\u201cGamma Sulfur\u201d May Hold the Key to Future Lithium-Sulfur Batteries"},"content":{"rendered":"\n

Sulfur (S) has seen itself in the center of several new developments in the field of battery engineering<\/a> as the material is often touted for its high energy capacity; new research from Drexel University<\/a> seems set on cementing sulfur\u2019s status in the field, as new findings from their research show that batteries may stand to benefit a lot from adapting a rare kind of sulfur called \u201cgamma\u201d sulfur.<\/p>\n\n\n\n

Technically, this rare form of sulfur is called monoclinic gamma-phase sulfur<\/em>, and its rarity is at least partly due to the fact that this particular sulfur form is hard to come by. Known production pathways in forming \u201cgamma sulfur\u201d are within oil wells or at high-temperature environments in laboratory settings.<\/p>\n\n\n\n

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The scientists used vapor deposition to lock sulfur inside the spaces within a carbon nanofiber mesh; instead, they found sulfur in a form that\u2019s rarely seen in both nature and the lab. Gamma sulfur may then prove useful in the development of stable sulfur-based batteries. (Pai et al, 2022)<\/figcaption><\/figure><\/div>\n\n\n\n

Drexel scientists wanted to create a way to confine sulfur in a carbon-based electrode to be used in batteries, given sulfur\u2019s unfortunate penchant for forming unwanted polysulfides during the electrochemical reactions that happen inside lithium-sulfur (Li-S) batteries.<\/p>\n\n\n\n

The hope was that by confining the sulfur within the carbon mesh, they would be able to limit the sulfur\u2019s exposure to the carbonate electrolyte that all too often lead to polysulfide formation\u2014especially given the fact that polysulfide buildup often leads to deteriorating battery performance and even failure.<\/p>\n\n\n\n

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The carbon nanofiber mesh produced by the research team contains spaces within its structure; the goal was to incorporate sulfur within the spaces to prevent it from forming polysulfides while in use in a battery. (Pai et al, 2022)<\/figcaption><\/figure><\/div>\n\n\n\n

However, Drexel researchers found themselves with a pleasant surprise as they attempted to use vapor deposition onto a carbon (C) nanofiber mesh to try and incorporate sulfur into its structure; instead of simply seeing sulfur locked inside, they instead found the rare \u201cgamma sulfur\u201d locked within the carbon nanofiber mesh\u2014and it just so happens that gamma sulfur was unreactive to the carbonate electrolyte, meaning no polysulfides to worry about. Their radical new battery technology was published as a paper in the journal Communications Chemistry<\/em><\/a>.<\/p>\n\n\n\n

\u201cAt first, it was hard to believe that this is what we were detecting because in all previous research monoclinic sulfur has been unstable under 95 \u00b0C (203 \u00b0F),\u201d said co-author Rahul Pai. \u201cIn the last century there have only been a handful of studies that produced monoclinic gamma sulfur and it has only been stable for 20-30 minutes at most. But we had created it in a cathode that was undergoing thousands of charge-discharge cycles without diminished performance \u2013 and a year later, our examination of it shows that the chemical phase has remained the same.\u201d<\/p>\n\n\n\n

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The schematic from the research team shows how the presence of gamma sulfur in their novel electrode prevents the formation of unwanted side-products during the electrochemical charge-and-discharge process. (Pai et al, 2022)<\/figcaption><\/figure><\/div>\n\n\n\n

“Having a cathode that works with the carbonate electrolyte that they’re already using is the path of least resistance for commercial manufacturers,” added Drexel\u2019s Department of Chemical and Biological Engineering<\/a> George B. Francis Chair professor Dr. Vibha Kalra in a Drexel University press release<\/a>. “So rather than pushing for the industry adoption of a new electrolyte, our goal was to make a cathode that could work in the pre-existing Li-ion electrolyte system.”<\/p>\n\n\n\n

The resulting gamma sulfur battery remained stable across 4,000 charge-discharge cycles across about one year of testing, with the prototype battery possessing triple the capacity of a standard lithium-ion battery.<\/p>\n\n\n\n

Finally, Dr. Kalra said to New Atlas<\/a>: \u201cWhile we are still working to understand the exact mechanism behind the creation of this stable monoclinic sulfur at room temperature, this remains an exciting discovery and one that could open a number of doors for developing more sustainable and affordable battery technology.\u201d<\/p>\n\n\n\n

References<\/h2>\n\n\n\n