eprintid: 10090156 rev_number: 26 eprint_status: archive userid: 608 dir: disk0/10/09/01/56 datestamp: 2020-01-23 15:42:12 lastmod: 2021-10-13 23:26:07 status_changed: 2020-01-23 15:42:12 type: article metadata_visibility: show creators_name: Lu, X creators_name: Bertei, A creators_name: Heenan, TMM creators_name: Wu, Y creators_name: Brett, DJL creators_name: Shearing, PR title: Multi-length scale microstructural design of micro-tubular Solid Oxide Fuel Cells for optimised power density and mechanical robustness ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F43 keywords: Anode microstructure, Knudsen diffusion, Tortuosity factor, Micro-channels, Triple phase boundary, Mass transport note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: In this study, we aim to parametrically reveal the dependence of electrochemical performance on a variety of microstructural characteristics at multi-length scale in a micro-tubular solid oxide fuel cell to shed light on the advanced electrode design. Numerical Direct Simulation Monte Carlo method is used on the tomographically-reconstructed 3D microstructure of the anode to characterise the tortuosity factors as a function of the porosity and pore diameter accounting for the Knudsen flow. These are subsequently incorporated in the mass transport in 2D electrochemical simulations. Results show that the Knudsen tortuosity factor is two times larger than that estimated by the continuum physics. High substrate porosity and pore size show unnoticeable effect in facilitating the mass transport provided that the micro-channels span over 60% of the radial thickness. The width and radial distribution of the micro-channels have little influence on the mass transport, but the compactness greatly affects the global performance. Optimal designs are identified as i) 80% micro-channel length and 27% substrate porosity to reach maximum power density (1.18 W cm−2) with lowered mechanical strength, or ii) 60% micro-channels length and 27% porosity to obtain a more balanced performance (0.96 W cm−2) with better long-term structural integrity. date: 2019-09-15 date_type: published publisher: ELSEVIER official_url: http://dx.doi.org/10.1016/j.jpowsour.2019.226744 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1667820 doi: 10.1016/j.jpowsour.2019.226744 lyricists_name: Brett, Daniel lyricists_name: Heenan, Thomas lyricists_name: Lu, Xuekun lyricists_name: Shearing, Paul lyricists_name: Wu, Yunsong lyricists_id: DBRET49 lyricists_id: THEEN37 lyricists_id: XLUAX78 lyricists_id: PSHEA33 lyricists_id: YWUDX61 actors_name: Dewerpe, Marie actors_id: MDDEW97 actors_role: owner full_text_status: public publication: Journal of Power Sources volume: 434 article_number: 226744 pages: 12 citation: Lu, X; Bertei, A; Heenan, TMM; Wu, Y; Brett, DJL; Shearing, PR; (2019) Multi-length scale microstructural design of micro-tubular Solid Oxide Fuel Cells for optimised power density and mechanical robustness. Journal of Power Sources , 434 , Article 226744. 10.1016/j.jpowsour.2019.226744 <https://doi.org/10.1016/j.jpowsour.2019.226744>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10090156/3/Lu_manuscript_doubleline_2nd%20round.pdf