All space missions are constrained by energy resources and necessitate efficient, durable, lightweight and compact energy devices. Energy thrust addresses these needs and cover three different schemes of energy conversion/harvesting: photovoltaic, electrochemical energy conversion and low thermal energy harvesting.
The specific aims include:
- Achieving significantly improved conversion efficiency and power per mass using a perovskite tandem cell that is molecularly designed to fully utilize the solar spectrum and other strategies.
- Meeting one of the biggest challenges in developing green energy conversion by developing free-standing 3D nanocarbon electrodes that monolithically integrate electrochemically and electrocatalytically active centers with a diffusion promoting outer layer.
- Realizing low-temperature, solid-state fuel cells for greatly enhanced performance and durability, Synthesizing new materials based on a low-energy driven conformational change for heliotropism and thermal energy harvesting.
1. Integrated light-weight photovoltaic devices
Space exploration requires photovoltaics (PV) power systems that are compact, robust and lightweight while offering competitive efficiency. Perovskites are known to have unusual photoelectronic properties that include direct bandgap, long-range carrier transport, ease of bandgap tuning and long carrier-recombination times.
We seek to achieve significantly enhanced power conversion efficiency and performance per mass through novel perovskite technologies.
2. Free-standing 3D Hierarchical Carbon and Electrocatalysis for oxygen reduction reaction
To achieve high-energy and high-power conversion, we are developing a well-defined 3D carbon hierarchical architecture that is composed of a free-standing 3D carbon scaffold with conformably grafted high-density electrochemically active species. To harness every active center in a 3D, a diffusion-promoting layer will be monolithically grafted onto the 3D structure.
Among various electrochemical reactions, oxygen reduction reaction (ORR; conversion of molecular oxygen into oxygen ion) is one of the most important challenges in electrocatalysis. Its kinetic sluggish nature has posed significant challenges in developing energy devices involving ORR (e.g. fuel cells and metal-air batteries) to a satisfactory level in terms of performance, durability and cost-competitiveness.
We seek to design and realize durable and high-performance SOFCs through a systematic study of ultrathin oxide coatings.
3. Low-energy-triggered switch
We have recently found that a very low energy stimulation, equivalent to only a few degrees centigrade fluctuation, can induce geometric changes in polymers that contain a small amount of sub-molecular conformational switch units. Motivated with this preliminary observation, we will synthesize a new series model compounds and corresponding polymer systems for maximizing thermal mechanoresponse.
We will also synthesize composites with other nanomaterials, which will serve as a template to guide the alignment of polymer chains. These nanostructure can serve as a strain energy converter (turning thermal fluctuations into electricity) or as solar energy absorber for heliotropism.