Capacitive Storage Science

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Capacitive Storage Science Chairs: Bruce Dunn (UCLA), Yury Gogotsi (Drexel) Panelists: Michel Armand (Amiens) Martin Bazant (MIT) Ralph Brodd (Broddarp) Andrew Burke (UC Davis) Ranjan Dash (Maxwell) John Ferraris (UT Dallas) Wesley Henderson (USNA) Sam Jenekhe (U. Washington) Katsumi Kaneko (Chiba Univ.) Prashant Kumta (Carnegie-Mellon) Keryn Lian (U. Toronto) Jeff Long (NRL) John Miller (JME) Katsuhiko Naoi (Tokyo Univ.) Joel Schindall (MIT) Bruno Scrosati (Rome) Patrice Simon (Toulouse) Henry White (Univ. Utah) Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Energy versus Control Supercapacitors connect amongst batteries and routine capacitors Energy – the ability to do work Power – how quick the vitality is conveyed Supercapacitors can accomplish more noteworthy vitality densities while as yet keeping up the powerful thickness of ordinary capacitors. Supercapacitors are a conceivably adaptable answer for an assortment of rising vitality applications in light of their capacity to accomplish an extensive variety of vitality and power thickness. Regone plot of vitality stockpiling systems* *Halper, M.S., & Ellenbogen, J.C., Miter Nanosystems Group, March 2006 Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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+ - Electrolyte Electrode Electrolyte Electrode M +n + - + - + - + - M +n+1 + - Capacitive Storage Systems Electrochemical Capacitors EC Double Layer Capacitor Pseudocapacitors Pseudocapacitance Charge exchange through surface Faradaic, redox responses Non-Faradaic (no exchange of charge) Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Electrochemical Double Layer Capacitors (EDLC) - + - + - + - + - + - + - Electrolyte + - + - + - + - + - + - + - + - Electrode E Charged EDLCs store charge electrostatically at cathode/electrolyte interface as charge partition. C dl : 10-50 m F/cm 2 * There is no charge exchange amongst terminal and electrolyte. Characteristically high power gadgets (short reaction time), constrained vitality stockpiling, high cycling solidness (~10 6 ). Diverse types of high surface territory carbon are utilized as a terminal material: activated carbon carbon aerogels carbon nanotubes *Conway, B. E., Birss, V. & Wojtowicz, J. Diary of Power Sources 66, 1-14 (1997) Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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An e - + Electrolyte Pseudocapacitors store by charge exchange amongst anode and electrolyte. The charge is exchanged at the surface or in the mass close to the surface through adsorption, redox response and intercalation of particles. Pseudocapacitors can accomplish higher particular capacitance and vitality thickness than EDLCs. ex. Hydrous RuO 2 (700+ F/g)* Electrode materials: Metal oxides Conducting polymers H + or Li + *Zheng, J.P., Jow, T.R., J. Control Sources 62 (1996) 155 Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Capacitive Devices and Systems How would we enhance the particular gravimetric and volumetric capacitance without trading off reaction time? Are awry designs (e.g. battery cathode/capacitor anode) a practical exchange off between lifetime decline and vitality thickness increment? Could frame element and bundling changes increment vitality and power thickness? Could we assemble multi-cells in a straightforward bundle? By what method would we be able to enhance the present gatherer properties (contact resistance, erosion resistance, and so on)? www.answers.com/theme/capacitor Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Materials for EDLCs What is the part of surface useful gatherings in deciding particular capcitance? How does the pore-strong design and nuclear course of action influence the high current thickness conduct of carbon? Could we plan this? What is the relationship between electrolyte particle size and pore estimate? Will a similar reliance be watched for anions and cations? Will carbon nanotubes convey a high particular capacitance and high power? A. G. Pandolfo, A. F. Hollenkemp, J. Control Sources 157 (2006) 11-27 Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Materials for Pseudocapacitors Are there materials that show vitality and power thickness superior to RuO 2 ? Are move metal non-oxides suitable materials for super-capacitors? How would they collaborate with the electrolyte? By what means can the synthetic strength be progressed? Could pseudocapacitance be included through synthetic or electrochemical alteration on top of EDLC to improve limit? By what means would we be able to adventure natural redox couples to enhance vitality/control thickness? Conway, B. E., Birss, V. & Wojtowicz, J. Diary of Power Sources 66, 1-14 (1997) H. Kim, B. Popov, J. Electrochemical Soc. 150 (2003) 1153 Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Electrolytes Are there natural electrolytes with the advantages of acetonitrile, without the security issues? In what manner would we be able to adventure ionic fluids to enhance security, temperature window, electrochemical window, and so on.? What impact do the IL anions and cations have separately on different properties (consistency, pore measure sieving, execution, and so forth.)? Shouldn't something be said about IL/natural blends? Polymer electrolytes? IL/polymer composites? Different blends/composites? lem.ch.unito.it/didattica/infochimica/Liquidi%20Ionici/Composition.html J. Chmiola et al., Science 313 (2006) 1760 Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Theory and Modeling How would we show electrostatic connections (i.e. move far from mean-field approximations)? What can hypothesis inform us regarding the twofold layer at the nano scale? How does pore size and geometry influence capacitance? What do we think about electron-exchange at the nano scale? Could we accomplish higher rates? Can we utilize hypothesis to distinguish new materials and structures for supercapacitors? How would we tentatively test/manage the models? electrochem.cwru.edu/ed/encycl/craftsmanship c03-elchem-cap.htm www-math.mit.edu/~bazant/look into/Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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Panel Discussions (Monday PM) * Sub-board Lead *Core essayist Basic Energy Sciences Workshop on "Capacitive Storage Science" April 2-5, 2007

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