{"429491":{"#nid":"429491","#data":{"type":"news","title":"Sol-gel Capacitor Dielectric Offers Record-high Energy Storage","body":[{"value":"\u003Cp\u003EUsing a hybrid silica sol-gel material and self-assembled monolayers of a common fatty acid, researchers have developed a new capacitor dielectric material that provides an electrical energy storage capacity rivaling certain batteries, with both a high energy density and high power density.\u003C\/p\u003E\u003Cp\u003EIf the material can be scaled up from laboratory samples, devices made from it could surpass traditional electrolytic capacitors for applications in electromagnetic propulsion, electric vehicles and defibrillators. Capacitors often complement batteries in these applications because they can provide large amounts of current quickly.\u003C\/p\u003E\u003Cp\u003EThe new material is composed of a silica sol-gel thin film containing polar groups linked to the silicon atoms and a nanoscale self-assembled monolayer of an octylphosphonic acid, which provides insulating properties. The bilayer structure blocks the injection of electrons into the sol-gel material, providing low leakage current, high breakdown strength and high energy extraction efficiency.\u003C\/p\u003E\u003Cp\u003E\u201cSol-gels with organic groups are well known and fatty acids such as phosphonic acids are well known,\u201d noted \u003Ca href=\u0022http:\/\/www.chemistry.gatech.edu\/people\/Perry\/Joseph%20W.\u0022\u003EJoseph Perry\u003C\/a\u003E, a professor in the \u003Ca href=\u0022http:\/\/www.chemistry.gatech.edu\/\u0022\u003ESchool of Chemistry and Biochemistry\u003C\/a\u003E at the Georgia Institute of Technology. \u201cBut to the best of our knowledge, this is the first time these two types of materials have been combined into high-density energy storage devices.\u201d\u003C\/p\u003E\u003Cp\u003EThe research, supported by the Office of Naval Research and the Air Force Office of Scientific Research, was reported July 14 in the journal \u003Cem\u003EAdvanced Energy Materials\u003C\/em\u003E.\u003C\/p\u003E\u003Cp\u003EThe need for efficient, high-performance materials for electrical energy storage has been growing along with the ever-increasing demand for electrical energy in mobile applications. Dielectric materials can provide fast charge and discharge response, high energy storage, and power conditioning for defense, medical and commercial applications. But it has been challenging to find a single dielectric material able to maximize permittivity, breakdown strength, energy density and energy extraction efficiency.\u003C\/p\u003E\u003Cp\u003EPerry and colleagues in Georgia Tech\u2019s \u003Ca href=\u0022http:\/\/www.cope.gatech.edu\/\u0022\u003ECenter for Organic Photonics and Electronics\u003C\/a\u003E (COPE) had been working on other capacitor materials to meet these demands, but were not satisfied with the progress. The hybrid sol-gel materials had shown potential for efficient dielectric energy storage because of their high orientational polarization under an electric field, so the group decided to pursue these materials for the new capacitor applications.\u003C\/p\u003E\u003Cp\u003EUsing an aluminized mylar film coated with the hybrid sol-gel capacitor material, they showed that the capacitor could be rolled and re-rolled several times while maintaining high energy density, demonstrating its flexibility. But they were still seeing high current leakage. To address that, they deposited a nanoscale self-assembled monolayer of n-octylphosphonic acid on top of the hybrid sol-gel. Less than a nanometer thick, the monolayer serves as an insulating layer.\u003C\/p\u003E\u003Cp\u003E\u201cOur silica sol-gel is a hybrid material because it has polar organic groups attached to the silica framework that gives the sol-gel a high dielectric constant, and in our bilayer dielectric, the n-octylphosphonic acid groups are inserted between the sol-gel layer and the top aluminum layer to block charge injection into the sol-gel,\u201d Perry explained. \u201cIt\u2019s really a bilayer hybrid material that takes the best of both reorientation polarization and approaches for reducing injection and improving energy extraction.\u201d\u003C\/p\u003E\u003Cp\u003EIn their structures, the researchers demonstrated maximum extractable energy densities up to 40 joules per cubic centimeter, an energy extraction efficiency of 72 percent at a field strength of 830 volts per micron, and a power density of 520 watts per cubic centimeter. The performance exceeds that of conventional electrolytic capacitors and thin-film lithium ion batteries, though it doesn\u2019t match the lithium ion battery formats commonly used in electronic devices and vehicles.\u003C\/p\u003E\u003Cp\u003E\u201cThis is the first time I\u2019ve seen a capacitor beat a battery on energy density,\u201d said Perry. \u201cThe combination of high energy density and high power density is uncommon in the capacitor world.\u201d\u003C\/p\u003E\u003Cp\u003EResearchers in Perry\u2019s lab have been making arrays of small sol-gel capacitors in the lab to gather information about the material\u2019s performance. The devices are made on small substrates about an inch square.\u003C\/p\u003E\u003Cp\u003E\u201cWhat we see when we apply an electric field is that the polarization response \u2013 which measures how much the polar groups line up in a stable way with the field \u2013 behaves in a linear way,\u201d said Perry. \u201cThis is what you want to see in a capacitor dielectric material.\u201d\u003C\/p\u003E\u003Cp\u003EThe next step will be to scale up the materials to see if the attractive properties transfer to larger devices. If that is successful, Perry expects to commercialize the material through a startup company or SBIR project.\u003C\/p\u003E\u003Cp\u003E\u201cThe simplicity of fully solution-based processes for our dielectric material system provides potential for facile scale-up and fabrication on flexible platforms,\u201d the authors wrote in their paper. \u201cThis work emphasizes the importance of controlling the electrode-dielectric interface to maximize the performance of dielectric materials for energy storage application.\u201d\u003C\/p\u003E\u003Cp\u003EIn addition to Perry, the research team included Yunsang Kim, Mohanalingam Kathaperumal and Vincent Chen from the Georgia Tech School of Chemistry and Biochemistry; Yohan Park from the Georgia Tech School of Materials Science and Engineering; Canek Fuentes-Hernandez and Bernard Kippelen from the Georgia Tech School of Electrical and Computer Engineering, and Ming-Hen Pan from the Naval Research Laboratory.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by the Office of Naval Research Dielectric Films Program (Grant N000141110462) and U.S. Air Force Office of Scientific Research, BioPAINTS MURI Program (Grant FA9550-09-0669). The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the sponsoring agencies.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Yunsang Kim, et al., \u201cBilayer Structure with Ultra-high Energy\/Power Density Using Hybrid Sol-Gel Dielectric and Charge Blocking Monolayer, (Advanced Energy Materials, 2015). \u003Ca href=\u0022http:\/\/www.dx.doi.org\/10.1002\/aenm.201500767\u0022\u003Ehttp:\/\/www.dx.doi.org\/10.1002\/aenm.201500767\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0181 USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) (404-894-6986)\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing a hybrid silica sol-gel material and self-assembled monolayers of a common fatty acid, researchers have developed a new capacitor dielectric material that provides an electrical energy storage capacity rivaling certain batteries, with both a high energy density and high power density.\u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have developed a new capacitor dielectric material that provides an electrical energy storage capacity rivaling certain batteries."}],"uid":"27303","created_gmt":"2015-07-29 20:50:05","changed_gmt":"2016-10-08 03:19:19","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2015-07-29T00:00:00-04:00","iso_date":"2015-07-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"429461":{"id":"429461","type":"image","title":"Sol-gel solution","body":null,"created":"1449254358","gmt_created":"2015-12-04 18:39:18","changed":"1475895167","gmt_changed":"2016-10-08 02:52:47"},"429441":{"id":"429441","type":"image","title":"Sol-gel materials","body":null,"created":"1449254358","gmt_created":"2015-12-04 18:39:18","changed":"1475895167","gmt_changed":"2016-10-08 02:52:47"},"429421":{"id":"429421","type":"image","title":"Testing sol-gel materials","body":null,"created":"1449254358","gmt_created":"2015-12-04 18:39:18","changed":"1475895167","gmt_changed":"2016-10-08 02:52:47"},"429451":{"id":"429451","type":"image","title":"Sol-gel samples","body":null,"created":"1449254358","gmt_created":"2015-12-04 18:39:18","changed":"1475895167","gmt_changed":"2016-10-08 02:52:47"},"429481":{"id":"429481","type":"image","title":"Perry research group","body":null,"created":"1449254358","gmt_created":"2015-12-04 18:39:18","changed":"1475895169","gmt_changed":"2016-10-08 02:52:49"}},"media_ids":["429461","429441","429421","429451","429481"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"144","name":"Energy"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"7564","name":"capacitor"},{"id":"136861","name":"dielectric"},{"id":"213","name":"energy"},{"id":"479","name":"Green Buzz"},{"id":"7435","name":"material"},{"id":"169747","name":"sol-gel"}],"core_research_areas":[{"id":"39531","name":"Energy and Sustainable Infrastructure"},{"id":"39471","name":"Materials"},{"id":"39491","name":"Renewable Bioproducts"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E404-894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}