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Development of electrode materials for molten carbonate fuel cells is a fundamental issue as a balance between mechanical and electrochemical properties is required due to the particular operating environments of these cells. As concern the anode, a viable strategy is to use nano-reinforced particles during electrodes' fabrication. Candidate nanomaterials comprise, but are not limited to, ZrO 2 , CeO 2 , TiO 2 , Ti, Mg, Al, etc. This work deals with the characterization and test of two different types of hard oxide nanoparticles as reinforce for NiAl-based anodes in molten carbonate fuel cells. Nano ceria and nano zirconia are compared each other and single cell test performances are presented. Compared to literature, the use of hard metal oxide nanoparticles allows good performance and promising perspectives with respect to the use a third alloying metal. However, nano zirconia performed slightly better than nano ceria as polarization and power curves are higher even if nano ceria has the highest mechanical properties. This means that the choice of nanoparticles to obtain improved anodes performance and properties is not trivial and a trade-off between relevant properties plays a key role. [ABSTRACT FROM AUTHOR]

The anode materials of MCFC require more investigations in order to boost performances at long term. In literature, many NiAl modified alloys have been proposed but not always enhanced cell performance and improved mechanical properties are achieved together. In this work, differently from previous literature, the use of Ti in a NiAl/Ti system is proposed as an effective strategy to enhance both mechanical and electrochemical properties. Results show that bending strength and stiffness increase whereas creep deformation under high pressure-temperature is lower, i.e. around 5–6%, compared to 7.5% of the standard benchmark. The preliminary cell tests carried out show also how the performance, in terms of current and voltage output, is better for anodes with Ti addition with a maximum power density of 165 mW cm −2 at 300 mA cm −2 for Ti 5% compared to 149 mW cm −2 of Ni5Al at the same current density. Finally, the best electrochemical behavior is found for the Ti 5% sample as it achieved the lowest internal and charge transfer resistance at the end of tests. These results suggest that NiAl/Ti systems can be eligible anode materials and are worthy to be investigated more in order to attract a renewed interest for development of MCFCs. [ABSTRACT FROM AUTHOR]

Anode materials in Molten Carbonate Fuel Cells should have high creep resistance and good mechanical behavior to endure in high temperature-corrosive environments. In this work, zirconia nanoparticles (1–10% wt.) are added to NiAl anodes in order to investigate their effects on mechanical properties and single cell performances. Results show that nanoparticles strongly adhere to metal particles and bending strength increases from 6.08 to 11.33 kg f cm −2 while creep strain is reduced from 7.55% to 3.25%. In the case of the anode with ZrO 2 3% wt., the stable and high output voltage of 0.81 V at 150 mA cm −2 is a promising result, compared to the literature. In addition, the solid contact angles between melted electrolyte and anode, for the NiAl reference sample and the ZrO 2 3% wt. are 37.6° and 17°, respectively, showing the improved wettability of the modified anode. However, it seems to be a limit to the effective zirconia content as the contact angle of the anode with ZrO 2 10% wt. is 58.1°, which indicates a low wetting ability. When zirconia content is too high, single cells have low performances due to high internal resistance and porosity reduction. The formation of a zirconate phase also occurs during operations. [ABSTRACT FROM AUTHOR]

• Novel low-cost graphite-cement composite for MFCs is studied. • SiO 2 nanoflowers are grown in the cementitious matrix. • GC70S shows superior characteristics compared to common felts. • Surface area, pore size distribution and biofilm adhesion are enhanced in GC70S. • Grown SiO 2 offers a solid anchorage also to larger yeast cells. Low cost graphite-cement composite (GC70S) is prepared by blending graphite, cement and fumed SiO 2 to obtain nanoflowers and proposed as an alternative to common carbon-based materials in the anode of biodevices with biofilm growth. The selected anodic benchmarks are carbon felt (CF) that is cheap, flexible, porous, and conductive three-dimensional support and a modified CF with polyethyleneimine (CF-PEI), where PEI is used to coat the carbon fibers. In spite of such advantages, CF has drawbacks, such as deformation by pore compression, hydrophobicity, low biofilm adhesion, and easy fragility by aging. Compared to these benchmarks, the GC70S has a multi-modal pore size distribution with micro (1–7 μm) and nano (20 nm) pores, whereas CF and CF-PEI only show macroscopic (55–60 μm) pores. The comparative results also show that the new composite provides better wettability, higher specific surface area (4.53·107 m2·m−3), and good electrical conductivity (2.04 ± 0.18 S·m−1). In half-cell tests, the yeast biofilm is firmly attached to GC70S anode, while its charge transfer resistance is greatly reduced. From the biofilm resistance contribution, the inhabitancy appears more abundant than in CF or CF-PEI. [ABSTRACT FROM AUTHOR]