Light Concentrator Sunlight
Solar Cell
Hydrogen Fuel
Mohammad H. Hashemi Optics Lab, IMT, EPFL SHINE Annual Meeting Bern, 2015
Fluidics
Water Splitting
shine.epfl.ch
Developing cost-based design rules
Rodriguez, et al. "Design and cost considera5ons for prac5cal solar-‐hydrogen generators." Energy & Environmental Science, 2014
Optimizing Solar-Hydrogen Production
Small Large electrolyzer electrolyzer
Optimal electrolyzer
Spanning a broad range of solar-H2 systems
Dumor5er & Haussener, in progress
H2 Cost and Sustainability Considerations
Current
Improving long-term performance
Voltage
1.9 V
Voc of Si cells should increase to have a sustainable and inexpensive hydrogen production.
Increased viability for Si devices
Increasing the VOC of Si based PV cells from 1.9 V to 2.3 V significantly improves the outputs of the devices
Components Overview Light Concentrator Sunlight
Solar Cell
Hydrogen Fuel
Fluidics
Water Splitting
Silicon PVs for Water Splitting Thin-Film Silicon Triple-Junction Solar Cells
Application as photocathode
Glass
SiOx
TCO Front: ZnO aSi (p-‐i-‐n) i-‐aSi ucSi (p-‐i-‐n)
SiOx ZnO Ti/Pt
Current status at CSEM: η=11.3 % at 1 sun; Voc = 2.23 V Potential sun to fuel efficiency: SFE=8.1%
Self Tracking Concentrator Lens array Waveguide Dichroic mirror membrane Phase change actuator
Zagolla, et al. "Self-‐tracking solar concentrator with an acceptance angle of 32°." Op5cs express, 2014
Concentrated Water-Splitting Device
Miniaturized Membrane-less Electrolyzer
O2 Hashemi, et al. "A membrane-‐less electrolyzer for hydrogen produc5on across the pH scale.“ Energy & Environmental Science, 2015
H2
High performance across the pH scale 1 M Sulfuric Acid with Pt Electrodes
1 M Neutral and Basic Electrolytes
Photoactive components and scale-up Demonstration of a Photoactive Device
Large Scale Implementation
Going from liquid to vapor operation
Modes5no, et al. "Vapor-‐fed microfluidic hydrogen generator." Lab on a Chip, 2015.
Optimizing performance for solar operation
Current Density [mA/cm2]
10
• Incorporating photo-
8
active electrodes – Low operating
6
currents
• Need to lower 4
electrochemical load • Better catalysts • Reduce ionic resistance
2
0 0
1
Potential [V]
2
3
Incorporating microstructured photocathodes
Project Achievements Scientific output: • 4 Patents • 10 Journal Publications Awards: • Foreign Policy Magazine's “100 Leading Global Thinkers” Prize • 2015 Energy and Environmental Science Readers' Award Lectureship • Best Student Presentation Award from the OSA, Energy and the Environment Congress
Acknowledgements SHINE Team Light Concentration (EPFL): C. Moser (PI), V. Zagolla Optofluidics (EPFL): D. Psaltis (PI), M. Modestino Modeling (EPFL): S. Haussener (PI), M. Durmotier, S. Tembhurne Photovoltaics (CSEM): J. Bailat (PI), D. Domine Catalysts (EMPA): A. Braun (PI), D. Bora
for tomorrow.
Thank You shine.epfl.ch