NSF Workshop on Emerging Opportunities of Nanoscience to Energy Conversion and Storage

Summary:

Intellectual Merit

Nanoscience is a highly dynamic and interdisciplinary area of basic research. Recent research breakthroughs in nanoscience is providing capabilities to organize materials at the molecular scale into complex patterns using various methodologies including self-assembly of viral, peptide and DNA nanostructures. Information Science has an important role, since Computer Science techniques are used in the design and simulation of these nanostructures. Other disciplines include Physics and Chemistry; for example attachment chemistries allow for the attachment of a wide variety of distinct materials (including metallic particles, proteins, and other inorganic and organic particles and compounds) to these nanostructures at chosen sites. However, to further drive the field of Nanoscience, there is an acute need to provide high impact applications beyond a limited number of known applications to nanoelectronics and medical science. This workshop explored the most promising emerging applications of Nanoscience to energy conversion and storage. The workshop explored possible methods for improved efficiency in the following tasks: (i) conversion to electricity of solar energy and/or heat (photo-voltaics and thermocouplers), and (ii) storage and release of energy (e.g., fuel cell and battery technology). Rather than conduct new research, the proposal tasks where restricted to study of research challenges, applications, and opportunities to NSF. To this end, the proposal requests NSF support for a limited scope NSF workshop on this topic, in the style of other NSF workshops in targeted areas of emerging interdisciplinary research. The Workshop was jointly co-Chaired by John Reif and John Monahan. The workshop brought together for the first time leading scientists with expertise in the relevant sub areas (e.g., self-assembly, quantum dots, nano-optics, DNA-metallic hybrids, etc.) to consider this topic. These experts \ranged over multiple disciplines including computer science, electrical engineering, chemistry, and physics. The workshop also included a number of leading relevant energy technology experts (in photo-voltaics, thermocouplers, fuel cell and battery technology) who will provide expertise on current the energy technologies and limitations.

Broader Impact

This NSF workshop wase highly interdisciplinary, with participants from various areas including Computer Scienc(who have expertise in the combinatorial design and computer simulation of the nano-devices to be considered), various Engineering disciplines (Electrical, Mechanical and Material) related to energy and nano-technologies, as well as Chemistry, Biochemistry, and Physics. It impacted both the research community in Nanoscience as well as other disciplines engaged in the study of energy technologies. To insure involvement by graduate students, a number of their travel and local expenses will be supported. The PI and his institution Duke University purely as a service - there was no overhead charged on any aspect of this Workshop. The workshop also benefited the NSF to allow for the identification of targeted research opportunities and challenges in applications of key importance to US economy and industry.

NSF Workshop: Emerging Opportunities of Nanoscience to Energy Conversion and Storage

Section 1: Introduction

by John H Reif and John Monahan

The global demand for energy is currently rising at a spectacular rate. The intensive search for new sources of energy, its storage and conversion has failed to keep up with demands. In a global sense we are living on borrowed time in terms of the current approaches of how we get, manipulate and store energy. Advances in nanotechnology have the potential to create new practical options to address a number of energy related issues. Nanotechnology may contribute in many ways; Be it from the largest electrical power generating sources to the very smallest portable electrical devices.

Energy transport in nanostructures differs significantly from macrostructures because of classical and quantum size effects on energy carriers such as phonons, electrons, photons, and molecules. Research is now concentrated on tailoring these nanoscale effects to develop more efficient energy conversion technologies in thermoelectrics, thermophotovotaics, fuel cells, batteries etc. In each case sufficient progress has been made to justify the infusion of further large research efforts to develop these technologies to a point that they can be commercialized and thereby practically address the world’s energy needs.

This two day conference brought together experts in the fields of Photovoltaics, Nanophotonics, Thermoelectric Energy, Fuel cell, Battery technology, Nanoelectronics and Nanoassembly to present and discuss the advances and issues in their field and outline how nanotechnology is helping these fields advance. If there was one theme that was all too apparent, it was that in each energy field an enormous body of work has already been invested by both the academic community and industry in that field over many years. Any further improvements in energy “trapping” ability, energy conversion or energy storage will come slowly and begrudgingly. In a number of cases the basic laws of physics become very relevant no matter how elegant the solution seems. That being said, there is room for improvement. Perhaps more so in the small scale energy needs than in the realm of large industrial power generating plants. In the case of the latter only photovoltaics currently seem to have the potential to have a significant practical impact in a commercial sense. However even here with the current “state of the art” research systems many hundreds of square miles of surface area would be needed to have any impact on the current power generation industry. Individual home or industrial instillations to cut peak power demand seem the best approach with our near term accomplishments in the solar energy field. Nanoelectronics has real potential here and good progress is being made.

When we drop down to smaller energy needs be it in transportation, home or portable uses the potential for nanotechnology to help increases greatly. Portable battery technology is a good example. Tremendous advances in the past decade have been made in this field. Almost every chemical mix of components has been tired and truly ingenious fabrication approaches have been used. Nanotechnology materials and methods are currently being pursuit in this field but it is important to appreciate that it is highly unlikely that there is a ten fold potential for storage capacity improvement. Not unless a completely new battery paradigm is discovered. Storing electrons chemically takes space and weight. Any commercial utilization of the resulting nanotechnology developments will have to carefully be examined in a strict cost and benefit analysis. This will be true for all energy systems but perhaps more so for small scale systems where mass production can be a major challenge.

Fuel cells have significant potential for increased efficiency utilizing nanotechnology. While a younger technology than batteries, the fields had developed fast. Issues of operating temperatures and manufacturing costs are major hurdles that must be addressed.

Thermoelectric devices are perhaps a unique area where applications are limited to small scale applications but again where nanotechnology based materials have provided a much needed impetus in advancing the overall efficiencies of these devices.

This article provides an overview of current developments in aspects of energy conversion and storage as they relate to the utilization on nanotechnology techniques and materials.