Wetting Behaviour of Candidate Molten Carbonate Fuel Cell Anode Materials and Electrolytes

The wetting of metals and oxides by molten carbonate is an important factor affecting the performance of a molten carbonate fuel cell (MCFC). The distribution of the electrolyte among electrodes and matrix in the MCFC is dominated by the pore characteristics and wetting properties of these components. However, data on wetting, especially under load (current passage), are limited. In this study, the behavior of the meniscus at a metal is used to obtain information on wetting and electrochemical reactions. Meniscus height and current were measured under varioius atmopsheres. The contact angle was calculated from the meniscus height. The electrolyte distribution in the MCFC was estimated using contact angles thus obtained in oxidant and reducing atmospheres. The results suggest that upon applicatioin of load the electrolyte moves from the anode to the cathode and that capillary effects can worsen the performance of a cell, especially if it is in an unbalanced state of electrolyte filling.

Section: Resultsmentioning

confidence: 99%

Meniscus Behavior of Metals and Oxides in Molten Carbonate under Oxidant and Reducing Atmospheres: I. Contact Angle and Electrolyte Displacement

Mugikura

Selman

1996

“…1 can be simplified to [2] The contact angle at NiO could not be obtained exactly, but it is close to zero because a NiO electrode is well wetted by electrolyte. Thus the maximum pore diameter occupied by electrolyte in the cathode at each position is as follows dc 1 ϭ dc 2 ϭ dc 3 ϭ иии ϭ dc i ϭ иии ϭ dc n [3] Putting dc i as dc, Eq. 2 is transformed as follows…”

Section: Pamentioning

confidence: 99%

An Electrolyte Distribution Model in Consideration of the Electrode Wetting in the Molten Carbonate Fuel Cell

Kawase

Mugikura

Watanabe

2000

In the molten carbonate fuel cell, the electrolyte distribution in the electrode is one of the major factors affecting cell performance. An electrolyte distribution model was developed in consideration of the electrode's wetting properties and the pore size distribution within the electrode. Because wettability data, e.g., contact angles, are required for model calculations, the meniscus heights of (Li/K)CO 3 and (Li/Na)CO 3 on Ni were measured under various anode gas conditions, and contact angles were derived.

“…The wettability of the alloy compared to pure Ni is influenced by additives. [9][10][11] Weewer et al 9 studied the wettability by various carbonate electrolytes of Ni-5 wt% Cr, Ni-5 wt% Al and Ni-5 wt% Cu under reducing atmosphere. Fisher et al 12 investigated the wettability of Ni-5.3 wt% Al, Ni-4.9 wt% Al and Ni-10 wt% Cr by Li 2 CO 3 -K 2 CO 3 eutectic under various gas atmospheres.…”

mentioning

confidence: 99%

Dynamic Wetting of Ni-Al Alloy Under MCFC Conditions

Gao

Selman

Nash

2020

Ni-Al alloy is one of the most commonly used anode materials in the molten carbonate fuel cell (MCFC). Wettability of the Ni-Al influences the active reaction area inside the porous anode and is therefore an important parameter in determining the performance of the cell. Moreover, the amount of carbonate in the electrode changes over the lifetime of a cell, and so does the extent of wetting. Therefore, the dynamic wetting of dense as well as porous substrates of Ni-Al alloy by molten carbonate was investigated. The effect of Al content on the dynamic wetting was investigated under both pure CO 2 and reducing (80%H 2 +20%CO 2 humidified at 45 °C) atmospheres. The contact angle on dense Ni-Al alloy decreased with increase of Al content under both atmospheres. It was higher under pure CO 2 atmosphere than under reducing atmosphere. The effects of porosity and of degree-of-filling (the amount of carbonate in relation to the empty pore volume available) on the time-dependent behavior of the contact angle were investigated, and the rate of absorption of molten carbonate into the substrate was measured. The absorption rate was significantly slowed down only when the molten carbonate added exceeded the volume of empty pores inside the substrate.