Alkaline Polymer Electrolyte Fuel Cells

Lead Research Organisation: University of Surrey
Department Name: Div of Chemical Sciences

Abstract

The first viable large scale fuel cell systems were the liquid electrolyte alkaline fuel cells developed by Francis Bacon. Until recently the entire space shuttle fleet was powered by such fuel cells. The main difficulties with these fuel cells surrounded the liquid electrolyte, which was difficult to immobilise and suffers from problems due to the formation of low solubility carbonate species. Subsequent material developments led to the introduction of proton-exchange membranes (PEMs e.g. Nafion(r)) and the development of the well-known PEMFC. Cost is a major inhibitor to commercial uptake of PEMFCs and is localised on 3 critical components: (1) Pt catalysts (loadings still high despite considerable R&D); (2) the PEMs; and (3) bipolar plate materials (there are few inexpensive materials which survive contact with Nafion, a superacid). Water balance within PEMFCs is difficult to optimise due to electro-osmotic drag. Finally, PEM-based direct methanol fuel cells (DMFCs) exhibit reduced performances due to migration of methanol to the cathode (voltage losses and wasted fuel).Recent advances in materials science and chemistry has allowed the production of membrane materials and ionomers which would allow the development of the alkaline-equivalent to PEMs. The application of these alkaline anion-exchange membranes (AAEMs) promises a quantum leap in fuel cell viability. The applicant team contains the world-leaders in the development of this innovative technology. Such fuel cells (conduction of OH- anions rather than protons) offer a number of significant advantages:(1) Catalysis of fuel cell reactions is faster under alkaline conditions than acidic conditions - indeed non-platinum catalysts perform very favourably in this environment e.g. Ag for oxygen reduction.(2) Many more materials show corrosion resistance in alkaline than in acid environments. This increases the number and chemistry of materials which can be used (including cheap, easy stamped and thin metal bipolar plate materials).(3) Non-fluorinated ionomers are feasible and promise significant membrane cost reductions.(4) Water and ionic transport within the OH-anion conducting electrolytes is favourable electroosmotic drag transports water away from the cathode (preventing flooding on the cathode, a major issue with PEMFCs and DMFCs). This process also mitigates the 'crossover' problem in DMFCs.This research programme involves the development of a suite of materials and technology necessary to implement the alkaline polymer electrolyte membrane fuel cells (APEMFC). This research will be performed by a consortium of world leading materials scientists, chemists and engineers, based at Imperial College London, Cranfield University, University of Newcastle and the University of Surrey. This team, which represents one of the best that can be assembled to undertake such research, embodies a multiscale understanding on experimental and theoretical levels of all aspects of fuel cell systems, from fundamental electrocatalysis to the stack level, including diagnostic approaches to assess those systems. The research groups have already explored some aspects of APEMFCs and this project will undertake the development of each aspect of the new technology in an integrated, multi-pronged approach whilst communicating their ongoing results to the members of a club of relevant industrial partners. The extensive opportunities for discipline hopping and international-level collaborations will be fully embraced. The overall aim is to develop membrane materials, catalysts and ionomers for APEMFCs and to construct and operate such fuel cells utilising platinum-free electrocatalysts. The proposed programme of work is adventurous: however, risks have been carefully assessed alongside suitable mitigation strategies (the high risk components promise high returns but have few dependencies). Success will lead to the U.K. pioneering a new class of clean energy conversion technology.
 
Description (1) Developed reference electrode system for measuring the individual anode and cathode performances in an operating alkaline membrane fuel cell;

(2) Developed an aqueous dispersible/soluble alkaline ionomer concepts for alkaline membrane electrode assembly fabrication;

(3) Developed a new class of radiation-grafted alkaline membrane and alkaline ionomer concept containing DABCO-type head-groups;

(4) Increase power densities obtainable in our simple hydrogen/oxygen fuel cell single cell set-up by 230% from the start of the grant.

All findings from this project have been rolled into further development in EPSRC grants EP/I004882/1 (John Varcoe's Leadership Fellowship) and EP/H025340/1. See outcomes for these grants for more details.
Exploitation Route Discussing the use of the polymer electrolyte technologies developed with various fuel cell, carbon dioxide utilisation, electrolyser, and salinity gradient power commercial concerns. Potential exploitation routes are being explored in the follow on EPSRC grants (see above).

An industry led grant application to the carbon-trust was unfortunately not successful.
Sectors Chemicals,Energy,Environment

URL http://www.surrey.ac.uk/chemistry/people/john_varcoe/
 
Description Findings used in follow-up EPSRC Fellowship (grant EP/I004882/1).
First Year Of Impact 2010
Sector Energy,Environment
 
Description EPSRC
Amount £388,982 (GBP)
Funding ID EP/H025340/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 06/2010 
End 12/2013
 
Description Multidisciplinary research into linking renewable energy with utilising atmospheric carbon dioxide and with water desalination
Amount £1,200,000 (GBP)
Funding ID EP/I004882/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2010 
End 12/2015
 
Description Collaboration with Wuhan University 
Organisation Wuhan University
Country China 
Sector Academic/University 
PI Contribution Supplied polymer electrolyte membranes and powders to Wuhan University for testing in their fuel cell systems with their ionomers.
Collaborator Contribution Testing Surrey membranes in their alkaline fuel cell systems. Obtained Chinese funding to allow John Varcoe (Fellow) to visit Wuhan in 2015.
Impact J. Ponce-Gonzalez, D. K. Whelligan, L. Wang, R. Bance-Soualhi, Y. Wang, Y. Peng, H. Peng, D. C. Apperley, H. N. Sarode, T. P. Pandey, A. G. Divekar, S. Seifert, A. M. Herring, L. Zhuang, J. R. Varcoe, "High performance aliphatic-heterocyclic benzyl-quaternary ammonium radiation-grafted anion-exchange membranes", Energy Environ. Sci., 9, 3724 (2016). J. R. Varcoe, P. Atanassov, D. R. Dekel, A. M. Herring, M. A. Hickner, P. A. Kohl, A. R. Kucernak, W. E. Mustain, K. Nijmeijer, K. Scott, T. Xu, L. Zhuang, "Anion-exchange membranes in electrochemical energy systems", Energy Environ. Sci., 7, 3135 (2014).
Start Year 2013
 
Description Collaboration with the General Research Institute of Non-Ferrous Metals (Beijing, China) 
Organisation General Research Institute of Non-Ferrous Metals (GRINM)
Country China 
Sector Private 
PI Contribution Signed an intent to collaborate with the General Research Institute of Non-Ferrous Metals (Beijing, China) on 18/10/2013. Includes an exchange of Surrey membranes for GRINM catalysts.
Collaborator Contribution Supplied catalyst to Surrey for evaluation.
Impact Joint paper: D. Jiang, R. Zeng, S. Wang, L. Jiang, J. R. Varcoe, "Paradox phenomena of proton exchange membrane fuel cells operating under dead-end anode mode", J. Power Sources, 265, 45 (2014).
Start Year 2013
 
Description University of Surrey - University of Science and Technology of China (Hefei, PR China) 
Organisation University of Science and Technology of China USTC
Country China 
Sector Academic/University 
PI Contribution Developing new membrane chemistries for alkaline anion-exchange membrane fuel cells. Exchange of materials. Testing of USTC Hefei membranes in Surrey Fuel Cell Test Stations
Collaborator Contribution Supply of USTC Hefei membranes to test in Surrey Fuel Cell Test Stations
Impact NSFC joint grant awarded (see further funding entry). Joint papers published: L. Wu, Q. Pan, J. R. Varcoe, D. Zhou, J. Ran, Z. Yang, T. Xu, "Thermal Crosslinking of an Alkaline Anion Exchange Membrane Bearing Unsaturated Side Chains", J. Membr. Sci., 490, 1 (2015). X. Lin, X. Liang, S. D. Poynton, J. R. Varcoe, A. Ong, J. Ran, Y. Li, Q. Li, T. Xu, "Alkaline anion exchange membranes containing pendant benzimidazolium groups for alkaline fuel cells", J. Membr. Sci., 443, 193 (2013). X. Lin, J. R. Varcoe, S. D. Poynton, X. Liang, A. Ong, J. Ran, Y. Li, T. Xu, "Alkaline polymer electrolytes containing pendant dimethylimidazolium groups for alkaline membrane fuel cells", J. Mater. Chem. A, 1, 7262 (2013). X. Lin, Y. Liu, S. D. Poynton, A. Ong, J. R. Varcoe, L. Wu, Y. Li, X. Liang, Q. Li, T. Xu, "Cross-linked anion exchange membranes for alkaline fuel cells synthesized using a solvent free strategy", J. Power Sources, 233, 259 (2013). Z. Zhang, L. Wu, J. Varcoe, C. Li, A. Ong, S. Poynton, T. Xu, "Aromatic polyelectrolytes via polyacylation of pre-quaternized monomers for alkaline fuel cells.", J. Mater. Chem. A, 1, 2595 (2013). X. Lin, L. Wu, Y. Liu, A. L. Ong, S. D. Poynton, J. R. Varcoe, T. Xu, "Alkali resistant and conductive guanidinium-based anion-exchange membranes for alkaline polymer electrolyte fuel cells", J. Power Sources, 217, 373 (2012). J. Ran, L. Wu, J. R. Varcoe, A. L. Ong, S. D. Poynton, T. Xu, "Development of imidazolium-type alkaline anion exchange membranes for fuel cell application", J. Membr. Sci., 415-416, 242 (2012). Y. Wu, C. Wu, J. R. Varcoe, S. D. Poynton, T. Xu, Y. Fu, "Novel silica/poly(2,6-dimethyl-1,4-phenylene oxide) hybrid anion exchange membranes for alkaline fuel cells: effect of silica content and the single cell performance", J. Power Sources, 195, 3069 (2010).
Start Year 2010