For lithium and lithium ion batteries new materials for electrodes such as LiMn2O4 spinels and nanostructured materials have been developed for use in battery and supercapacitor electrodes.
Electrolytic systems based on ionogenic polymers and viologenes, as well as their complexes with organic and inorganic (nano-particle) compounds for Li batteries polymer electrolyte and fuel cell polymer membranes.
New LiMn2O4 spinel materials have been synthesized that can yield higher power densities than cobalt oxides. The improved capability for supplying quick bursts of power are makes spinel cathode batteries of great interest in power-hungry applications such as cell phones. Because they are thermally stable and not prone to the thermal runaway reactions associated with cobalt oxide cathode materials, spinel cathodes are intrinsically much safer.
Synthesis of new anode materials for Li-ion secondary batteries from modified graphite has been developed using of natural, metallurgical and synthetic graphites as starting materials.Themodified graphite is characterized by high discharge capacity and can be used for preparing anodes without binder.
In photovoltaics the creative use of doping elements and combinations of various forms of silicon, along with improved encapsulation and protective materials, allows improvements in most types of devices. The following approaches are under development to fabricate solar cells that are less expensive, on a per watt-hour basis, than currently available photovoltaic technologies.
- Photovoltaics based on hetero-junctions comprising mono-crystalline silicon, nano-porous silicon, or nano-crystalline silicon doped with rare-earth elements.
- Applying nano-porous silicon with predetermined sizes of nano-crystals provides maximum light absorption while decreasing the recombination loss both in the bulk volume and on the crystal surface.
- Nanocrystalline silicon enables control of the width of semiconductor prohibited zone over a wide dynamic range by means of changes in morphological structure.
- Doping with rare-earth elements provides increasing photosensitivity in the shorter wavelength region of the spectrum, as well as stability against reaidation that is especially significant in the production thin-film solar batteries for aerospace applications.
For supercapacitors, new electrode material deposition processes and treatments that greatly reduce the internal resistance between the current collector and electrode bulk material have been developed.
For fuel cells, high performance ionomers for fuel cell and solid polymer electrolyte applications can operate at higher temperatures than current membrane materials, and are less expensive to produce. These membrane materials make possible the operation of conventional PEM fuel cells at higher temperatures where they operate more efficiently.
For hybrid autonomous power sources
comprising lithium batteries and solar cells, solar cell components are based on nano-crystalline silicon and hetero junction structures. These systems feature low degradation rate and improved solar energy conversion efficiency.