Mass Transport Phenomena in a MCFC Cathode

TL;DR

This paper develops and compares three models of ion transport in a molten carbonate fuel cell cathode, identifying limiting cases and optimizing diffusivity to enhance performance and durability.

Contribution

It introduces three one-dimensional models of MCFC cathode transport processes and assesses their validity, providing insights for optimizing cell performance.

Findings

Existence of a limiting ion migration case depending on liquid conductivity.

Optimized diffusivity improves cell performance and longevity.

Model comparisons highlight key transport mechanisms.

Abstract

A molten carbonate fuel cell (MCFC) is an electro-chemical energy conversion technology that runs on natural gas and employs a molten salt electrolyte. In order to keep the electrolyte in this state, the cell must be kept at a temperature above 500 C, eliminating the need for precious metals as the catalyst. There has been only a limited amount of research on modelling the transport processes inside this device, mainly due to its restricted applicability for mobile applications. In this work, three one-dimensional models of a MCFC cathode are presented based on different types of diffusion and convection. Comparisons between models are performed so as to assess their validity. Regarding ion transport, it is shown that there exists a limiting case for ion migration across the cathode that depends on the conductivity for the liquid potential. Finally, an optimization of the diffusivity across the cathode is carried out in an attempt to increase the cell performance and its longevity.