Celtec

Recently, Fujifilm Celtec has proposed new negative electrode materials with excellent electrochemical properties tin-based amorphous oxides containing elements of groups III, IV, and V, such as boron and phosphorus. These materials show high specific capacity, up to 600 Ah kg and 2200 Ah [146]. 

PEMEAS, a 2004 spin-off from Celanese AG, has developed a membrane made from the heat-resistant polymer PBI. The PBI membrane marketed by PEMEAS under the brand name Celtec enables a fuel cell to operate at temperatures of up to 200°C (392°F), while more conventional technologies allow PEMFC-operating temperatures of up to 100°C (212°F). Due... 

Celtec - P MEA current-voltage curve under hydrogen... 

Celanese AG has reported reasonable long-term durability and operational stability for Celtec P MEAs (Figure 27.73). The properties of Celtec P MEAs, according to Celanese, are given in Table 27.17. 

The properties of Celtec P MEAs, according to Celanese, are given in Table 21.10. 

A commercial phosphoric acid doped PBI membrane, Celtec V by BASF Fuel Cells, tailored for DMFC is based in a blend of PBI and poly(vinyl phosphonic acid) (PVPA). The PVPA poly acid is immobilized in the PBI matrix by interpenetration, crosslinking and covalent bonding [201]. 

H3PO4 doped PBI membranes (A = 2.5) 100 pm thick exhibit methanol crossover current densities less than 10 mA.cm [403, 410], while the PBI/PVPA composite commercial membrane Celtec-V shows crossover current densities higher than 100 mA.cm at 90 °C in 1 M methanol [201]. 

An isomer of ABPBI which contains head-to head and tail-to-tail benzimidazole sequences, was recently synthesized [449] and membranes were prepared by using the PPA sol- gel process (see Fig. 6.11). The membranes, like those prepared with PBI using this method PBI [200], have a much higher doping degree and their conductivities are above 200 mS.cm at 180 °C, even without humidihcatimi. Proton conductivities above 200 mS.cm were also reported for commercial crosslinked ABPBI membranes by Fumatech [425, 447], at 120 and 140 °C and partial humidification. ABPBI/MMA membranes exhibit only modest conductivities [419, 445], while an ABPBI/PVPA composite [450], which is the equivalent to the commercial PBI-based Celtec V by BASF Fuel Cells shows a poor conductivity. 

Gubler L, Kramer D, Belack J, Unsal O, Schmidt TJ, Scherer GG (2007) Celtec-V. A polybenzimidazole-based membrane for the direct methanol fuel cell. J Electrochem Soc... 

Another prorrtising modification of PBI is the introduction of immobilized polyvirtylphosphonic acid (PVPA) in the PBI matrix. This approach is especially interesting since the acid is not likely to be washed out dttring operation, thus maintaining steady fuel cell performance. PEMEAS-BASF Fuel Cells has developed an MEA product, Celtec -V, mainly for liqttid feed DMFCs, based on this concept Single-cell performance tests of CeltecV and Na... 

Properties of high-temperature PEFC Celtec -P 1000 MEAs in start/stop operation mode. J. Power Sources, 176, 428-434. 

In the following sections, recent model approaches for HT-PEFCs are reviewed. A more detailed discussion about the role of the electrolyte is presented in Section 29.4 without claiming to be a perfect explanation. In Section 29.5, a very basic approach to modeling the polarization curve of an HT-PEFC is discussed using the example of a Celtec MEA from BASF. The intention is to demonstrate the consequences of the unique behavior of the electrolyte, which is discussed in Section 29.4. 

The fitted values for the parameters were obtained from experiments with a single testing cell, operated at 160°C. The MEA (Celtec) was obtained from BASF, which is one of the most widely used at present The active area was 16.65 cm and the mean resistance was Rq = 0.1 cm. ... 

Figure 29.4 Polarization curves for a single-cell HT-PEFC with Celtec MEA, operated at 150°C with pure hydrogen-air and a stoichiometric ratio of 2 2.

High-Temperature Polymer Electrolyte Fuel Cells, Fig. 3 Long-term durability of H2-Air HT-PEFCs (a) MEA using Advent TPS at 180 °C, 1 baTa, H2-Air stoich. 1.2/2 and (b) BASF Celtec P 1,000 (PBI) MEA at 160 °C, 1 bara, Hz-Air stoich. 1.2/2... 

Fig. 13.17 Polarization curves of a Celtec -P MEA [94]. The blue line represents using hydrogen/air as fuel/oxidant. The gray line represents a steam reformate of 70% H2, 29% CO2, and 1% CO/air...

Mocoteguy P, Ludwig B, Scholia J, Barrera R, Ginocchio S (2009) Long term testing in continuous mode of HT-PEMFC based H3PO4/PBI Celtec-P MEAs for u-CHP applications. 

BASF Fuel Cell GmbH (2010) Celtec MEAs membrane electrode assemblies for high temperature PEM fuel cells, http //www.basf-fuelcell.com/en/projects/celtec-mea.html... 

Belack J, Kundler I, Schmidt TJ (2008) Celtec-MEAs life time, degradation modes and mitigation strategies. Paper presented at Progress MEA 2008, La Grande Motte, 21-24 September 2008... 

Fig. 10.18 Celtec-PlOOO MEA performance and degradation (single-cell data, 50 cm, 1.7 mg cm total Pt loading), (a) H2-air and reformate-air polarization curves at 180 °C, 1 bara, stoichiometry 1.2/2, reformate composition 70 % H2, 2 % CO, balance CO2 (nonhumidified gases), (b) anode overpotential versus pure hydrogen...

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