{"452231":{"#nid":"452231","#data":{"type":"news","title":"Proposed Standards for Triboelectric Nanogenerators Could Facilitate Comparisons","body":[{"value":"\u003Cp\u003EMore than 60 research groups worldwide are now developing variations of the triboelectric nanogenerator (TENG), which converts ambient mechanical energy into electricity for powering wearable electronics, sensor networks, implantable medical devices and other small systems.\u003C\/p\u003E\u003Cp\u003ETo provide a means for both comparing and selecting these energy-harvesting nanogenerators for specific applications, the Georgia Institute of Technology research group that pioneered the TENG technology has now proposed a set of standards for quantifying device performance. The proposal evaluates both the structural and materials performance of the four major types of TENG devices.\u003C\/p\u003E\u003Cp\u003E\u201cTriboelectric nanogenerators are a new energy technology that has shown phenomenal potential,\u201d said \u003Ca href=\u0022http:\/\/www.mse.gatech.edu\/faculty\/wang\u0022\u003EZhong Lin Wang\u003C\/a\u003E, a Regents professor in the Georgia Tech \u003Ca href=\u0022http:\/\/www.mse.gatech.edu\/\u0022\u003ESchool of Materials Science and Engineering.\u003C\/a\u003E \u201cHere, we have proposed standards by which the performance of these devices can be quantified and compared. These standards will be useful for academic researchers developing the devices and for future industrial applications of the nanogenerators.\u201d\u003C\/p\u003E\u003Cp\u003EThe proposed standards are described in an article published September 25 in the journal \u003Cem\u003ENature Communications\u003C\/em\u003E.\u003C\/p\u003E\u003Cp\u003ETriboelectric nanogenerators use a combination of the triboelectric effect and electrostatic induction to generate small amount of electrical power from mechanical motion such as rotation, sliding or vibration. The triboelectric effect takes advantage of the fact that certain materials become electrically charged after they come into moving contact with a surface made from a different material. The electricity generated by TENG devices could replace or supplement batteries for a broad range of potential applications.\u003C\/p\u003E\u003Cp\u003EDeveloped over the past several years, the technology has advanced to the point where it can power small electronic devices, potentially enabling widespread sensing and infrastructure systems \u2013 as well as powering wearable consumer devices.\u003C\/p\u003E\u003Cp\u003E\u201cBecause of the large number of devices being developed, people need to have a standard for judging the performance of these nanogenerators,\u201d Wang said. He noted that standards have allowed technologies such as photovoltaics and thermoelectric devices to advance, though the performance of TENG devices is more difficult to quantify because of the different design and materials options available.\u003C\/p\u003E\u003Cp\u003EIn their paper, Wang\u2019s team proposes a general figure of merit which can be used to quantify the potential energy output of the TENG devices. The general figure of merit is made up of information from two other sources: the capabilities of the specific TENG structure used, and the surface charge density provided by the specific materials chosen to construct the device. The output is compared to the mechanical energy inputs to provide an efficiency comparison.\u003C\/p\u003E\u003Cp\u003EThese measurements are based on plots of the build-up of voltage and total transferred electrical charges from each device. The structural figures of merit are derived from theoretical calculations for each of the four major nanogenerator modes, plus experimental results produced by TENG devices placed into a circuit with a switch and an electrical load. The materials figure of merit depends on experimental measurements of the surface charge density done with an experimental set-up that uses liquid metal to collect the surface charge.\u003C\/p\u003E\u003Cp\u003EVariations in TENG structures allow a variety of applications depending on the source of mechanical energy. The four major groups include (1) vertical contact-separation mode, (2) lateral sliding mode, (3) single-electron mode, and (4) freestanding triboelectric-layer mode. There are also hybrid combinations of these major structural modes.\u003C\/p\u003E\u003Cp\u003EThe contact-separation mode, for example, is powered by a periodic driving force that causes repeated contact, and then separation, between two dissimilar materials that have coated electrodes on the top and bottom surfaces. The lateral sliding model uses two surfaces that briefly slide together, then separate, generating a charge.\u003C\/p\u003E\u003Cp\u003E\u201cWe can calculate for the four modes what are the best sizes and shapes, and the best power output you can expect for a specific structural figure of merit,\u201d Wang explained.\u003C\/p\u003E\u003Cp\u003EMaterial choices tested include fluorinated ethylene propylene, Kapton, polarized polyvinylidene fluoride, polyethylene, natural rubber and cellulose.\u003C\/p\u003E\u003Cp\u003EThe measurement and theoretical techniques were developed by postdoctoral fellow Yunlong Zi and graduate student Simiao Niu, both members of Wang\u2019s research team. In developing their proposed standards, the researchers considered what had already been done in setting standards for heat engines and other technologies.\u003C\/p\u003E\u003Cp\u003E\u201cFor triboelectric generators, because the mechanical input is varied, you have different kinds of measurements to evaluate the performance,\u201d said Zi. \u201cThese figures of merit are considerably more complicated than would be needed for characterizing solar cell performance, for example.\u201d\u003C\/p\u003E\u003Cp\u003EPublishing the proposed standards is a first step in what Wang expects to be a long process of gaining acceptance. He plans to spend the next several months explaining the standards to other research groups developing TENG devices.\u003C\/p\u003E\u003Cp\u003EHe estimates that there could be 60 research groups around the world working on TENG devices, and he expects that number to grow as the nanogenerators become more sophisticated and powerful.\u003C\/p\u003E\u003Cp\u003E\u201cAs wearable electronics become more popular and fashionable, we will need a better way to power them,\u201d Wang said. \u201cTriboelectric nanogenerators can play a large role in that. We have spent a lot of time improving the power efficiency, and the field is quickly expanding.\u201d\u003C\/p\u003E\u003Cp\u003EUltimately, he said, the standards could also be modified for piezoelectric generators and other systems designed to produce electricity from mechanical motion.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Yunlong Zi, et al., \u201cStandards and Figures of Merit for Quantifying the Performance of Triboelectric Nanogenerators,\u201d (Nature Communications, 2015). (\u003Ca href=\u0022http:\/\/dx.doi.org\/10.1038\/NCOMMS9376\u0022\u003Ehttp:\/\/dx.doi.org\/10.1038\/NCOMMS9376\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)\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ETo provide a means for both comparing and selecting energy-harvesting nanogenerators for specific applications, the Georgia Tech research group that pioneered the TENG technology has now proposed a set of standards for quantifying device performance. The proposal evaluates both the structural and materials performance of the four major types of TENG devices.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have proposed standards for comparing and selecting triboelectric nanogenerators."}],"uid":"27303","created_gmt":"2015-09-25 10:06:44","changed_gmt":"2016-10-08 03:19:36","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2015-09-25T00:00:00-04:00","iso_date":"2015-09-25T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"452201":{"id":"452201","type":"image","title":"Developing TENG standards","body":null,"created":"1449256280","gmt_created":"2015-12-04 19:11:20","changed":"1475895194","gmt_changed":"2016-10-08 02:53:14","alt":"Developing TENG standards","file":{"fid":"203367","name":"teng-standards001.jpg","image_path":"\/sites\/default\/files\/images\/teng-standards001_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/teng-standards001_0.jpg","mime":"image\/jpeg","size":5504631,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/teng-standards001_0.jpg?itok=vmjKaAAv"}},"452211":{"id":"452211","type":"image","title":"Triboelectric nanogenerators","body":null,"created":"1449256280","gmt_created":"2015-12-04 19:11:20","changed":"1475895194","gmt_changed":"2016-10-08 02:53:14","alt":"Triboelectric nanogenerators","file":{"fid":"203368","name":"teng-standards002.jpg","image_path":"\/sites\/default\/files\/images\/teng-standards002_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/teng-standards002_0.jpg","mime":"image\/jpeg","size":1367081,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/teng-standards002_0.jpg?itok=VzWbZ1tH"}}},"media_ids":["452201","452211"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"144","name":"Energy"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"213","name":"energy"},{"id":"13689","name":"energy harvesting"},{"id":"1334","name":"nanogenerator"},{"id":"107","name":"Nanotechnology"},{"id":"37991","name":"triboelectric"},{"id":"142711","name":"triboelectric nanogenerator"},{"id":"13751","name":"Zhong Lin Wang"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39531","name":"Energy and Sustainable Infrastructure"},{"id":"39471","name":"Materials"}],"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":""}}}