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Rational design strategy for optimization of clamping pressure to minimize contact resistance between electrode and current collector while preserving porosity of electrodes in water electrolyzers
Author(s) -
Kishor Koshal,
Parashtekar Alhad,
Saha Sulay,
Sivakumar Sri,
Ramkumar Janakaraman,
Pala Raj Ganesh S.
Publication year - 2018
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23036
Subject(s) - clamping , porosity , contact resistance , materials science , electrode , electrolysis , current collector , composite material , current (fluid) , gas diffusion electrode , electrolyte , layer (electronics) , chemistry , mechanical engineering , electrical engineering , engineering
The compressive clamping pressure at the interface of gas‐diffusion‐layer (GDL) and current collector decreases the contact resistance between them though it reduces the porosity and surface roughness of electrocatalysts, which would in turn decrease the efficiency of an electrolyzer. We explore these issues of trade‐off between porosity versus contact resistance and provide a design heuristic for optimum clamping pressure. The present work provides an estimate of the optimal value of clamping pressure for an alkaline water electrolyzer having membrane electrode assembly (MEA), taking account of the variation in porosity of catalyst layers and contact resistance obtained via half‐cell studies performed at different pressures. Towards this, we define the performance‐index (Φ) which is the ratio of Faradaic current density and resistances resulting from contact‐interfaces in electrolyzers and we suggest that the maxima in Φ corresponds to optimum clamping pressure.