Shine

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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


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