자료유형 | E-Book |
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개인저자 | Mei, Bing-Ang. |
단체저자명 | University of California, Los Angeles. Mechanical Engineering 0330. |
서명/저자사항 | Physical Interpretations and Electrode Design Guidelines for Electrochemical Capacitors. |
발행사항 | [S.l.] : University of California, Los Angeles., 2018 |
발행사항 | Ann Arbor : ProQuest Dissertations & Theses, 2018 |
형태사항 | 221 p. |
소장본 주기 | School code: 0031. |
ISBN | 9780438010901 |
일반주기 |
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Adviser: Laurent G. Pilon. |
요약 | Electrochemical capacitors (ECs) serve as promising electrical energy storage systems due to their potential to achieve both high energy and high power densities. They can be classified as either electric double layer capacitors (EDLCs) or pseudocapacitors depending on the charge storage mechanism. EDLCs store charge in the electric double layer (EDL) forming at the electrode/electrolyte interface. Pseudocapacitors store energy both in the EDL and in the redox reactions occurring at or near the electrode surface along with ion intercalation into the electrodes. However, the interpretations of experimental results and the electrode optimization of such systems are made difficult by the coupling effect of EDL formation, redox reactions, and ion intercalation in the multidimensional porous electrode structures. This dissertation presents rigorous physical interpretations of conventional experimental characterization methods and provides design rules for EC electrodes using a multidimensional physicochemical model. |
요약 | First, electrochemical impedance spectroscopy (EIS) measurements (Nyquist plots) of planar EDLC electrodes and devices were reproduced numerically for different electrode conductivity and thickness, electrolyte domain thickness, as well as ion diameter, diffusion coefficient, and concentrations. The electrode resistance, electrolyte resistance, and the equilibrium differential capacitance were identified from Nyquist plots without relying on equivalent RC circuits. These results and interpretations were then confirmed experimentally for EDLC devices consisting of two identical activated-carbon electrodes in both aqueous and non-aqueous electrolytes. Similarly, EIS measurements of planar redox active electrodes were reproduced numerically for a wide range of electrode electrical conductivity, electrolyte thickness, redox reaction rate constant, and bias potential. The electrode, bulk electrolyte, charge transfer, and mass transfer resistances could be identified from the Nyquist plots. The results were then confirmed experimentally for LiNi0.6Co0.2 Mn0.2O2 and MoS2 electrodes in organic electrolytes. |
요약 | Moreover, multidimensional simulations under cyclic voltammetry were performed for EDLC electrodes of different thicknesses consisting of spherical nanoparticles arranged in either simple cubic (SC) or face-centered cubic (FCC) packing structure. The capacitance under quasi-equilibrium (low charging/discharging rate) and rate-dependent (high charging/discharging rate) conditions were compared for different electrode nanoarchitectures and design suggestions were drawn. Moreover, multidimensional simulations were carried out for pseudocapacitive electrodes consisting of ordered conducting nanorods coated with a thin film of pseudocapacitive material. The contributions of EDL formation and redox reactions were discriminated and an optimum pseudocapacitive layer thickness that maximized total areal capacitance was identified as a function of scan rate and confirmed by scaling analysis. |
요약 | Finally, commonly used methods to calculate energy and power densities of EDLC and hybrid pseudocapacitors were compared and evaluated. Energy conservation law was applied to the devices to identify the most appropriate method to calculate energy and power densities. The findings were confirmed by experimental measurements on EDLCs made of activated carbon electrodes and organic electrolyte and on hybrid pseudocapacitors made of MnO2-graphene and activated carbon electrodes in aqueous electrolyte. |
일반주제명 | Mechanical engineering. |
언어 | 영어 |
기본자료 저록 | Dissertation Abstracts International79-10B(E). Dissertation Abstract International |
대출바로가기 | http://www.riss.kr/pdu/ddodLink.do?id=T15013676 |
인쇄
No. | 등록번호 | 청구기호 | 소장처 | 도서상태 | 반납예정일 | 예약 | 서비스 | 매체정보 |
---|---|---|---|---|---|---|---|---|
1 | WE00026381 | 621 | 가야대학교/전자책서버(컴퓨터서버)/ | 대출가능 |