Shaping the Future of Energy Storage With Conductive Clay

altIn the race to find materials of ever increasing thinness, surface area and conductivity to make better performing battery electrodes, a lump of clay might have just taken the lead. Materials scientists from Drexel University’s College of Engineering invented the clay, which is both highly conductive and can easily be molded into a variety of shapes and sizes. It represents a turn away from the rather complicated and costly processing—currently used to make materials for lithium-ion batteries and supercapacitors—and toward one that looks a bit like rolling out cookie dough with results that are even sweeter from an energy storage standpoint.

With the publication of their recipe for “conductive MXene clay” in the Dec. 4 edition of Nature, the researchers suggest a significant shift in the way electrodes for storage devices are produced.

Researchers at Drexel University have developed a way to make a highly conductive clay from MXene and water.

The clay, which already exhibits conductivity on par with that of metals, can be turned into a film—usable in an electrode—simply by rolling or pressing it.

“Both the physical properties of the clay, consisting of two-dimensional titanium carbide particles, as well as its performance characteristics, seem to make it an exceptionally viable candidate for use in energy storage devices like batteries and supercapacitors,” said Yury Gogotsi, PhD, Distinguished University and Trustee Chair professor in the College of Engineering, and director of the A.J. Drexel Nanomaterials Institute, who is a co-author of the paper. “The procedure to make the clay also uses much safer, readily available ingredients than the ones we used to produce MXene electrodes in the past.”

The key to the utility of this material, according to Michel Barsoum, PhD, Distinguished professor in the College of Engineering and one of the inventors of MXenes, is in its form.
“As anybody who has played with mud can attest, clay is hydrophilic –water-loving,” Barsoum said. “Clay is also layered and when hydrated, the water molecules slide between the layers and render it plastic that in turn can be readily shaped into complex shapes. The same happens here; when we add water to MXene, water penetrates between the layers and endows the resulting material with plasticity and moldability. Graphene—a material widely studied for use in electrodes- on the other hand, is conductive but does not like water—it is hydrophobic. What we discovered is a conductive two-dimensional layered material that also loves water. The fact that we can now roll our electrodes rapidly and efficiently, and not have to use binders and/or conductive additives renders this material quite attractive from a mass production point of view.”
A graphic illustration of the properties of MXene clay.The discovery came about while Michael Ghidiu, a doctoral student advised by Barsoum and Gogotsi in the Department of Materials Science and Engineering at Drexel, was testing a new method for making MXenes—two-dimensional materials invented at Drexel that are among the leading candidates for use in next-generation batteries and supercapacitors.

Straying slightly from the original chemical etching process pioneered at Drexel, which uses highly toxic hydrofluoric acid, Ghidiu instead used a fluoride salt and hydrochloric acid to etch aluminum out of a titanium-based, layered ceramic material called a MAX phase—also discovered at Drexel by Barsoum. These two ingredients, which are household names in chemistry class and are also much safer to handle than hydrofluoric acid, reduced the MAX phase to a pile of black particles. To stop the reaction and remove any residual chemicals, Ghidiu washed the material in water. But rather than finding the familiar layered MXene particles, he discovered that the etched sediment absorbed the water to form a clay-like material.

“We expected to find a slightly different material coming from the new process—but nothing like this,” Ghidiu said. “We were just hoping for a safer, less expensive way to make MXenes, when something even better landed on the table.”
clay rolling

One of the first tests the team performed on the clay was to see if it could be pressed into a thin layer while retaining its conductive properties—after all, its initial goal was to make a conductive film.

“Being able to roll clay into a film is quite a contrast in production time, safety and cost when compared to the two most common practices for making electrode materials,” Ghidiu said. “Both the etching and peeling process used to make MXenes and a flaking, filtration and deposition method—like paper making—employ strong acids and costly, less common materials. The clay-making process is much simpler, quicker and safer.”

MXene clay made by researchers at Drexel University can be rolled into any thickness while retaining its conductivity.  With the new discovery, all these steps are avoided, greatly simplifying the processing. Now the researchers can simply etch the MAX phase, wash the resulting material and roll the resultant clay into films of various thicknesses.

“I would say the most important benefit to the new method—besides its increased capacitance—is that we can now make an electrode ready-to-go in about 15 minutes, whereas the total process before from the same starting point would be on the order of a day,” Ghidiu said.

The availability of its ingredients also makes the clay rather appealing from a production standpoint.

“Being able to make a conductive clay, essentially out of titanium carbide with the help of a common fluoride salt and hydrochloric acid is the materials equivalent of making a chocolate chip cookie—everybody has these ingredients in the pantry,” said Barsoum.

But a question that resounds through most materials research of this nature is, of course: what can it do with an electrical charge?

Thorough investigation of the clay’s electrochemical performance, conducted by Maria Lukatskaya a doctoral student advised by Gogotsi and Barsoum, which was reported in the paper, indicated that the clay’s ability to store an electrical charge is three times that reported for MXenes produced by hydrofluoric acid etching. This means it could find uses in the batteries that power cell phones and start cars, or even in a supercapacitor that could one day help renewable energy sources fit into a regional power grid.
clay circuit

“Keep in mind this is the very first generation of the material that we’re testing,” Lukatskaya said. “We haven’t done a thing to augment its abilities, and at 900 F/cm3 it’s already showing a higher capacitance per unit of volume than most other materials. We’re also reporting that it does not lose any of its capacitance through more than 10,000 charge/discharge cycles, so we’re talking about quite a special lump of clay here.”

Changing materials scientists’ medium from film to clay presents a variety of new avenues for research and manufacturing. The clay can be molded into any shape. It could also be watered down into a conductive paint that hardens within a few minutes while still retaining its conductive properties. This means it could have applications in batteries, conductive transparent coatings and reinforcement for composites among others.
An electron microscopic study of the clay particles dispersed in water, conducted by co-author Mengqiang Zhao, PhD, a post-doctoral researcher in Gogotsi’s group, showed that the clay is made up of single layers of MXene about one nanometer—just a few atoms—thick. This atomically thin structure indicates that researchers are likely to find that the clay has many attractive electronic and optical properties as they continue to learn more about it.   

“We plan to keep pushing forward with our study of this new material in hopes of developing a truly scalable manufacturing process, improving quality and yield of MXene and exfoliating other MAX phases to produce new MXenes, which could not be synthesized using the previously used process—the possibilities seem endless. While it might look like just a bit of clay, I believe this discovery will reshape research in the field going forward.” Barsoum said.

This work was supported by the Ceramics Program of the National Science Foundation and by the U.S. Department of Energy’s FIRST Energy Frontier Research Center.

Source: http://drexel.edu/now/archive/2014/November/MXene-clay/

Related Articles:

 

 

Drexel Engineers Improve Strength, Flexibility of Atom-Thick Films - a conductive polymer MXene nanocomposite

A scanning electron microscopic image of MXene-polymer nanocomposite shows the polyvinyl alcohol filling in the layers of MXene to give the material its unique properties.Flexible new material, which the group has identified as a conductive polymer nanocomposite, is the latest expression of the ongoing research in Drexel’s Department of Materials Science and Engineering on a family of composite two-dimensional materials called MXenes

 

Flexible and conductive MXene films and nanocomposites with high capacitance

altTwo-dimensional transition metal carbides (MXenes) offer a quite unique combination of excellent mechanical properties, hydrophilic surfaces, and metallic conductivity.

 

 

 

 

News from MRC.ORG.UA

Congratulations to Professor Yury Gogotsi who received prestigious Chineese Government Friendship Award, Beijing, Great Hall of the People, September 29, 2018

Yury Gogotsi recevide Friendship Award from Chinas GovernmentChina"s Government Friendship Award ceremony was held in Great Hall of the People, in Beijing on September 29, 2018, the award to the winners were presented by the Vice Premier of China Liu He. The People's Republic of China Government Friendship Award is China's highest award for foreign experts who have made outstanding contributions to the country's economic and social progress.

 
Spray-On Antennas Could Be the Tech Connector of the Future

Invisibly thin MXene antennas can be applied to a variety of substrates and perform better than antenna materials currently used in mobile devices.

Now, researchers at Drexel University have developed a method for creating nearly invisible antennas on almost any surface by literally spraying them on like paint. The antennas are made from a special two-dimensional metallic material called MXene. MXene powder can be dissolved in water to create a paint that is then airbrushed on. In tests, even a layer as thin as just 62 nanometers – thousands of times thinner than a sheet of paper – could communicate effectively. Performance maxed out at just 8 microns, a point at which the spray-on antennas worked just as well as those currently used in mobile devices and wireless routers.

 
Congratulations to professor Yury Gogotsi, professor Rodney S. Ruoff and professor Patrice Simon with being named by Clarivate Analythics among of the 17 most cited and influenced world-class scientists in 2018!

Professor Yury GogotsiThis designation celebrates researchers whose influence is comparable to that of Nobel Prize recipients, as attested by exceptionally high citation records within the Web of Science. 

 
15th YES Annual Meeting: “The Next Generation of Everything” September 13 – 15, 2018

alt

Yalta European Strategy (YES)  introduced nightcap events for the participants of the 15th YES Annual Meeting to wind down at the end of the first conference day and discuss interesting topics in an informal atmosphere. YES invited leading politicians, opinion makers and business leaders to present their views on modern trends that define the world and Ukraine. The nightcaps were organized in partnership with the U.S. Embassy in Ukraine and America House, International Renaissance Foundation, Ukrainian-Jewish Encounter and the Atlantic Council, Mejlis of the Crimean Tatar people and Ministry of Information Policy of Ukraine, Western NIS Enterprise Fund and Embassy of the Republic of Estonia.

 
2018 IEEE 8th International Conference on Nanomaterials: Applications & Properties, September 09-14, 2018

2018 IEEE International Conference on “Nanomaterials Applications & Properties”At the poster session of the conference Oleksiy Gogotsi presented two poster presentations on advanced nanomaterials for different applications, prepared with colleagues from Drexel University, USA, and Jilin University, China

 
NANO2DAY project participants Oleksiy Gogotsi and Veronika Zahorodna visited Polymer Institute SAS, Bratislava, Slovakia, July-September 2018

altNANO2DAY project participants from Materials Research Centre, Kiev, Ukraine, MRC director and project leader Oleksiy Gogotsi and ESR Veronika Zahorodna are working in Polymer Institute, Slovak Academy of Sciences, Bratislava, Slovakia under the project secondments plan.

 
NANO2DAY project: Professor Maria Omastova, Polymenr Institue Slovak Academy of Science, visited Materials Research Centre, Kiev, Ukraine, July-August 2018

Professor Maria Omastova, Polymer Institute SAV, Bratislava, Slovakia, and Oleksiy Gogotsi, director of Materials Research Centre, Kiev, Ukraine,  July 2018Professor Omastova was acquainted with the activities and research infrastructure of MRC project partner, she held several seminars on polymer composites and talked about the experience and developments of her institute. 

 
The 6th International Conference on Novel Functional Carbon Nanomaterials at the 8th Forum on New Materials (CIMTEC 2018) in Perugia, Italy, June 11-14

Фото Yury Gogotsi.The 6th International Conference “Novel Functional Carbon Nanomaterials”within the 8th Forum on New Materials at CIMTEC 2018 held in Perugia, Italy,  highlighted recent achievements and challenges in the synthesis, structural control and modeling at the meso- and nano-scales of the variety of low-dimensional carbon allotropes including nanodiamonds, diamond-like carbon, fullerenes, nanotubes, graphene and graphene-related structures, as well as high surface area carbon networks, which are promising for a range of emerging applications in energy conversion and storage, water purification, high-speed nanoelectronics, optoelectronics, photonics, quantum information processing, quantum computing, biosensing, drug delivery, medical imaging, thermal management, catalysis, lubrication, etc.

 
1st International Conference on MXenes at Jilin University, Changchun, China

MXene conference 2018The meeting is the first international conference focusing on MXene materals, which is to bring scientists in the two-dimensional materials or energy area to interact and discuss the advances and challenges in various fields.

 
Our Congratulations to Prof. Gogotsi with Receiving an Honorary Doctorate from Kyiv Polytechnic Institute KPIthe National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute"

 Prof. Yury Gogotsi received an honorary doctorate from the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic InstituteOn May 14th, 2018, Prof. Yury Gogotsi received an honorary doctorate from the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute (NTUU “KPI”), Kiev, Ukraine.

 
H2020-MSCA-RISE Nano2Day Kick-off project meeting, Academic Centre of University of Latvia, Riga, 10-11 May 2018

altH2020-MSCA-RISE project „Multifunctional polymer composites doped with novel 2D nanoparticles for advanced applications NANO2DAY” started on May 1, 2018. It is aimed to develop novel multifunctional composites with outstanding electronic and mechanical properties by incorporation of novel MXene nanosheets into polymer matrixes.

 
Materials Research Center team visited the Training " on "How to write a successful proposal in Horizon 2020" at National Aviation University of Ukraine" as part of the NAU Info Day

horizon2020 семінарOn February 14, 2018, Materials Research Center team visited the Training " on "How to write a successful proposal in Horizon 2020" at National Aviation University of Ukraine"  as part of the NAU Info Day.

 
Paper on Rheological Characteristics of 2D Titanium Carbide (MXene) Dispersions: A Guide for Processing MXenes

Processing guidelines for the fabrication of MXene films, coatings, and fibers have been established based on the rheological propertiesProcessing guidelines for the fabrication of MXene films, coatings, and fibers have been established based on the rheological properties.

 
Professor Yury Gogotsi will give a lecture on 2D materials MXenes in Stanford University

altProfessor Yury Gogotsi will give a lecture on 2D materials MXenes on MSE winter Colloquim in Materials Science and Engineering Department, Stanford University. 

 
MXene is one of the most sensitive gas sensors ever reported

MXene gas sensorsMXene is one of the most sensitive gas sensors ever reported that sniff out chemicals in the air to warn us about everything from fires to carbon monoxide to drunk drivers to explosive devices hidden in luggage have improved so much that they can even detect diseases on a person’s breath. Researchers from Drexel University and the Korea Advanced Institute of Science and Technology have made a discovery that could make our best “chemical noses” even more sensitive.