360 likes | 572 Views
Proton Exchange Membrane Fuel Cells – Fundamentals and Applications 質子交換膜燃料電池 --- 原理與應用. C. W. Lin Department of Chemical Engineering National Yunlin University of Science & Technology. Fuel cell technology. A Dream , Challenge Or A Necessity.
E N D
Proton Exchange Membrane Fuel Cells – Fundamentals and Applications 質子交換膜燃料電池---原理與應用 • C. W. Lin • Department of Chemical Engineering • National Yunlin University of Science & Technology
Fuel cell technology A Dream , Challenge Or A Necessity
Fuel cell as energy converter Mechanical energy conversion Thermal energy conversion Chemical energy of the fuels Electrical energy conversion
A fuel cell consists of two electrodes sandwiched around an electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat. + - H H H2 O + O2 - H H + - H H2 H O2 + O - H H National Yunlin University of Science & Technology Functional Polymer Lab.
High energy-conversion efficiency Thermodynamic efficiency for fuel cells and Carnot efficiency for heat engines
What is a fuel cell? Proton and hydroxyl conducting fuel cells
Modular design Fuel cells for different scale applications
Small transportation Can we apply small technologies to become more sustainable?
DMFC: Working principle e e CH3OH+H2O CO2+6H++6e Anode O2+4H++4e 2H2O Cathode H+ transport H2O CH3OH O2 H2O fuel crossover D R Y H+ transport Catalyst poisoning Pt-CO fuel crossover H2O CO2 H+ transport
Methanol crossover Hybrid membranes, nanocomposites, etc Catalyst poisoning (Pt-CO) Better complex catalyst (Pt-X), higher temperature (>120°C) Slow “water shift reaction” (CH3OH+H2O CO2+6H++6e) below ~100 °C Better complex catalyst, higher temperature But the higher the temperature, the worse the water balance in membrane Water-free membranes? DMFC: Problems and possible solutions
PEMFC: Water balance in membrane e e H2 2H++2e Anode O2+4H++4e 2H2O Cathode H+ transport H2O H2 O2 H2O H2O diffusion D R Y W E T Electro-osmotic drag H+(H2O) H2O diffusion H2O H+ transport Water balance in polymer membrane.