Mesa+ Meeting

Thematic Sessions

1Early diagnostics of diseases, chaired by dr.ir. Loes Segerink & prof.dr.ir. Albert van den Berg

2Unconventional electronics, chaired by prof.dr.ir. Wilfred van der Wiel & prof.dr.ing. Guus Rijnders

3Storage and conversion of renewable energy, chaired by prof.dr. Guido Mul & dr.ir. Mark Huijben

4Water, chaired by prof.dr.ir. Rob Lammertink & dr.ir. Wiebe de Vos

Storage and conversion of renewable energy (ROOM 7)

Chairs: prof.dr.ir. Guido Mul (Photocatalytic Synthesis) & dr.ir. Mark Huijben (Inorganic Materials Science)

INTRODUCTION

Renewable energy will increasingly contribute to the energy demand of the world society, which is projected to grow to 20 TW in 2020. A problem of various renewable sources is their intermittency in supply (e.g. wind speed, day-night or summer-winter cycles). To balance supply and demand, existing technologies need to be significantly improved, or new technologies developed, to store renewable energy in times when supply exceeds demand, and which can easily be made available in times when demand exceeds supply.

This session will give a (limited) overview of research activities in the MESA+ institute focused on energy storage. The audience is stimulated to be inspired by the presentations and to contribute to the discussions, as well as to provide novel ideas for energy storage on the basis of their own research activities. This includes identifying funding opportunities for energy storage-related research. The program of this session is as follows.

PROGRAM

ABSTRACTS

Photoelectrochemical Hydrogen Production – Water Splitting and Beyond Water Splitting

Dr. Bastian Mei (Photocatalytic Synthesis)

Energy storage due to the intermittencies of renewable energy sources in fuels such as hydrogen and hydrocarbons is essential to succeed in the transition to 100% renewable energy. Hydrogen can be produced using different approaches, i.e. electrolysis of water powered by renewable sources of energy, like wind or sunlight. Additionally, an integrated photoelectrocatalytic (PEC) approach, where solar energy is directly converted into hydrogen is a possibility. From a global energy perspective the need for reactants that are scalable to the terawatt level has usually entailed that the oxidation process must be water splitting to oxygen. Nevertheless, implementation of (especially) integrated PEC devices is hampered by the economics of the overall process. Thus, this presentation focuses on different approaches to produce hydrogen with integrated photoelectrocatalytic systems. First, conventional photoelectrochemical designs to produce hydrogen by water splitting will be discussed and finally strategies to produce solar hydrogen with an economic “advantage” will be presented.

Storage of hydrogen in nanostructured materials

Dr. Geert Brocks (Computational Materials Science)

Both the intermittent nature of energy production by renewable sources such as solar or wind, and the off-grid use of energy in, for instance, cars and other mobile applications, call for a solution to the problem of energy storage. Hydrogen can be such a storage medium, as it can be produced from electricity (by the electrolysis of water), and converted into electricity (in hydrogen fuel cells). Hydrogen in gaseous form has the drawback of needing high pressures (~70 MPa) to achieve meaningful energy densities, whereas liquid hydrogen requires a very low temperature (< 30 K). Storage of hydrogen as solid-state-hydride compounds presents an option to obtain a high density. The (de)hydrogenation reactions of these solid state compounds tend to be slow, however. Nanosizing and scaffolding is currently an important strategy to improve the kinetics and thermodynamics for hydrogen storage in such compounds. An alternative way of storing hydrogen consists of adsorption of hydrogen molecules inside nanoporous materials, such as metal-organic frameworks (MOFs). Here the bottleneck is formed by the hydrogen adsorption enthalpy, which is frequently too low. In this talk I will give a short overview of recent developments in nanostructured and nanoporous materials for hydrogen storage.

Enhancing the energy storage density and rate capability in solid state batteries

Prof. dr. Andre ten Elshof (Inorganic & Hybrid Nanomaterials Chemistry)

The rise in electrical power generation from sun and wind, and the need to replace carbon fuel vehicles by electrical vehicles (EV) demands development of novel, cheap, up-scalable and sustainable battery technologies with high energy density and rate capability. With the development of highly Li-conductive solid state electrolytes the all solid state Li-ion battery comes within reach, promising improved safety and higher energy densities compared to liquid electrolyte-based Li-ion batteries. The main hurdle towards employing these solid electrolytes is the limited Li-ion charge transport over the solid-solid electrode-electrolyte interface. In this presentation strategies to mitigate the interface resistance and current research activities to improve interfacial transport by 3D structuring of the electrode-electrolyte interface are discussed.

Towards Renewable Energy via Semi Solid Flow Batteries

Dr. Michel Duits (Physics of Complex Fluids)

Semi Solid Flow Batteries offer great potential for not only storage, but also quick replenishment of energy, due to the dispersed state of the electrochemically active material as nanoparticles in a liquid medium. Since the SSFB concept was only recently introduced, several design aspects (formulation, packing density, pumping losses, ...) offer room for performance enhancement, via a better understanding of the underlying physical and chemical processes. In the context of an EU collaboration (http://fp7-influence.eu/), research at MESA+ is focused on understanding the rheology and conductivity of mixtures of Carbon Black and Lithium based mineral oxide particles in organic solvent. Simultaneous measurements of mechanical and electrical impedance are combined with separate studies into the colloidal interactions, which underlie the self-assembly of particle networks in the fluid. Also the effects of prolonged shearing and (dis)charging on the properties of the battery fluids are studied. An overview of progress along the different lines will be given.