Umang Gupta Chair Professor
Professor, Department of Mechanical Engineering

and Materials Science Programme
Indian Institute of Technology Kanpur

Kanpur 208016, UP, India

                                           Phone: (+91) (512) 2597687/2598703/(+91) (0)9415081153

                                                                                                     Fax: (+91) (512) 2597408

IIT-Kanpur

Positions are available for highly motivated & hardworking doctoral & postdoctoral fellows

Area of Interests

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Working Principle Polymer Electrolyte Membrane Fuel Cells

Polymer electrolyte membrane fuel cells (PEMFCs) are low operating temperature fuel cells (FCs) consisting of a polymer membrane as electrolyte. As the polymer membranes conduct H⁺ ions, PEMFCs are also termed as proton exchange membrane FCs. They use hydrogen or low molecular weight hydrocarbons as the fuel at anode and oxygen/air as the oxidizer at cathode. Among others, hydrogen, being one of the potential futuristic energy sources, is the key fuel for PEMFCs. Apart from H₂-based PEMFCs, methanol-based PEMFCs, namely DMFCs have been studied thoroughly due to their feasibility for small-scale portable applications. In principle, both of these fuel cells have similar structures. Present study is focused on the H₂-based PEMFCs due to their prospective application potential in domestic stationary as well portable devices, public transport, etc.

In a PEMFC, hydrogen is oxidized at anode to produce H⁺ ions, which migrate through the PEM to the cathode. Reduction of oxygen takes place at cathode to form O^2- ions, which combine with the H⁺ ions to form H₂O. This develops a net cell potential that equals to the difference between electrochemical potentials of hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR). When connected to an external load, a constant current can be drawn if the reactant gases are supplied and the reaction product (H₂O) is removed continuously to maintain the system in steady state.

Figure shows the schematic of H₂-O₂ PEMFC with various components such as, bipolar plates (BPs) with flow channels, gas diffusion layer (GDL) and membrane electrode assembly (MEA). The MEA is the part of FC consisting of the cathode and anode catalyst layers, and the PEM itself. Each of these components use different materials based on their particular functions. However, a practical FC consists of more components for continuous power generation. As shown in Figure, it has to perform a number of tasks such as (i) supply and transport of fuel and oxidant to the appropriate electrodes, (ii) removal of by-products, (iii) electron transfer to the external load, (iv) H⁺ ion transport through the membrane, (v) proper humidification of membrane, and (vi) maintaining the temperature at an optimum level. For high power generation, FC units are stacked in a series by using BPs. In a FC stack, other auxiliary components such as the humidifier, heat exchanger, compressor, heating system, etc. may be required occasionally.

It consists of

     -Outer plates

    -Spacer plates

    -Silicone gasket

    -End plates

    -Gas diffusion layer

    -Catalyst Layer

    -Polymer electrolyte membrane

    -Gas connections

Would you like to work on any one of these components to improve the performance of fuel cell?