A Microscale Modeling Tool for the Design and Optimization of Solid Oxide Fuel Cells

Shixue Liu,Zijing Lin,Wei Kong

doi:10.3390/en20200427

Abstract

A two dimensional numerical model of a solid oxide fuel cell (SOFC) with electrode functional layers is presented. The model incorporates the partial differential equations for mass transport, electric conduction and electrochemical reactions in the electrode functional layers, the anode support layer, the cathode current collection layer and at the electrode/electrolyte interfaces. A dusty gas model is used in modeling the gas transport in porous electrodes. The model is capable of providing results in good agreement with the experimental I-V relationship. Numerical examples are presented to illustrate the applications of this numerical model as a tool for the design and optimization of SOFCs. For a stack assembly of a pitch width of 2 mm and an interconnect-electrode contact resistance of 0.025 Ωcm2, a typical SOFC stack cell should consist of a rib width of 0.9 mm, a cathode current collection layer thickness of 200–300 μm, a cathode functional layer thickness of 20–40 μm, and an anode functional layer thickness of 10–20 μm in order to achieve optimal performance.

Highlights

Solid oxide fuel cells (SOFCs) are clean and efficient chemical to electrical energy transfer devices.A traditional solid oxide fuel cell (SOFC) includes three layers: porous anode, dense electrolyte and porous cathode [1,2].The fuel and air are transported from the gas channels to the three phase boundary (TPB) near the electrode/electrolyte interfaces through the porous electrodes and the electrochemical reactions take place in the TPBs
The air and the fuel are supplied to the reaction sites in the functional layers (CFL and anode functional layer (AFL)) from the gas channels through the outside porous layers (CCCL and anode support layer (ASL))
At the AFL reaction site, the oxygen ion reacts with a hydrogen molecule and produces a water molecule and two electrons and the electrons are conducted to the nearest anodic interconnect rib

Summary

Introduction

The thin functional layers, CFL and AFL, are designed to increase the TPB length with low porosity and small particle sizes. The thick layers, CCCL and ASL, are of high porosity and large particle sizes to enable easy gas transport to the functional layers

Methods

Results

Conclusion