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Modeling the Performance of an Integrated Photoelectrolysis System with 10× Solar Concentrators

Chen, Yikai and Xiang, Chengxiang and Hu, Shu and Lewis, Nathan S. (2014) Modeling the Performance of an Integrated Photoelectrolysis System with 10× Solar Concentrators. Journal of the Electrochemical Society, 161 (10). F1101-F1110. ISSN 0013-4651. https://resolver.caltech.edu/CaltechAUTHORS:20141001-112924015

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Abstract

Two designs for an integrated photoelectrolysis system that uses a 10× concentrating solar collector have been investigated in detail. The system performance was evaluated using a multi-physics model that accounted for the properties of the tandem photoabsorbers, mass transport, and the electrocatalytic performance of the oxygen-evolution and hydrogen-evolution reactions (OER and HER, respectively). The solar-to-hydrogen (STH) conversion efficiencies and the ohmic losses associated with proton transport in the solution electrolyte and through the membrane of the photoelectrolysis system were evaluated systematically as a function of the cell dimensions, the operating temperatures, the bandgap combinations of the tandem cell, and the performance of both the photoabsorbers and electrocatalysts. Relative to designs of optimized systems that would operate without a solar concentrator, the optimized 10× solar concentrator designs possessed larger ohmic losses and exhibited less uniformity in the distribution of the current density along the width of the photoelectrode. To minimize resistive losses while maximizing the solar-to-hydrogen conversion efficiency, η_(STH), both of the designs, a two-dimensional “trough” design and a three-dimensional “bubble wrap” design, required that the electrode width or diameter, respectively, was no larger than a few millimeters. As the size of the electrodes increased beyond this limiting dimension, the η_(STH) became more sensitive to the performance of the photoabsorbers and catalysts. At a fixed electrode dimension, increases in the operating temperature reduced the efficiency of cells with smaller electrodes, due to degradation in the performance of the photoabsorber with increasing temperature. In contrast, cells with larger electrode dimensions showed increases in efficiency as the temperature increased, due to increases in the rates of electrocatalysis and due to enhanced mass transport. The simulations indicted that cells that contained 10% photoabsorber area, and minimal amounts of Nafion or other permselective membranes (i.e. areal coverages and volumetric fractions of only a few percent of the cell), with the remaining area comprised of a suitable, low-cost inert, non porous material (flexible polymers, inert inorganic materials, etc.) should be able to produce high values of η_(STH), with η_(STH) = 29.8% for an optimized design with a bandgap combination of 1.6 eV/0.9 eV in a tandem photoabsorber system at 350 K.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://jes.ecsdl.org/content/161/10/F1101PublisherArticle
http://dx.doi.org/ 10.1149/2.0751410jesDOIArticle
ORCID:
AuthorORCID
Xiang, Chengxiang0000-0002-1698-6754
Hu, Shu0000-0002-5041-0169
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© The Author(s) 2014. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. Manuscript submitted June 13, 2014; revised manuscript received July 10, 2014. Published August 1, 2014. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. The authors thank John C. Stevens for helpful discussion regarding the optics of solar concentrator designs. Authors Yikai Chen and Chengxiang Xiang contributed equally to this work.
Group:JCAP
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Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Issue or Number:10
Record Number:CaltechAUTHORS:20141001-112924015
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141001-112924015
Official Citation:Yikai Chen, Chengxiang Xiang, Shu Hu, and Nathan S. Lewis Modeling the Performance of an Integrated Photoelectrolysis System with 10 × Solar Concentrators J. Electrochem. Soc. 2014 161(10): F1101-F1110; doi:10.1149/2.0751410jes
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50146
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:01 Oct 2014 20:32
Last Modified:09 Oct 2019 04:13

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