Energy conversion devices

The ECP/CNM nanocomposites are very suitable candidates for application in energy conversion devices like solar cells, thermoelectric generators, fuel cells, etc. Many of the multifunctional ECP/CNM nanocomposites are used as electrodes for energy conversion devices. 

The ECP/CNM nanocomposites are mainly used as counter electrodes in solar cells like dye-sensitized solar cells, for example, PEDOT PSS/ graphene nanocomposite film electrodes [81]. The optical transparency and the high conductivity of these nanocomposite films have increased 

Graphene-based ECP nanocomposites have found application in energy harvesting systems such as thermoelectric generators. For example, PEDOT PSS/graphene nanocomposite films have shown a power factor of 45.7 pWm K when used in an organic thermoelectric device [80]. 

In PEM fuel cells (PEMFCs), the function of catalyst support layer is to accommodate the catalyst nanoparticles. Nanocomposite such as PEDOT/ carbon nanofiber has proved to be an efficient catalyst support in PEMFCs [40]. 

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A fuel cell is equivalent to a generator it converts a fuel s chemical energy directly into electricity. The main difference between these energy conversion devices is that the fuel cell acccomplishes this directly, "without the two additional intermediate steps, heat release and mechanical motion. 

Many of these steps include CVD, and CVD is now a major process in the fabrication of monolithic integrated circuits (IC), custom and semi-custom ASIC s, active discrete devices, transistors, diodes, passive devices and networks, hybrid IC s, opto-elec-tronic devices, energy-conversion devices, and microwave devices. 

The materials and processes used in the manufacture of photoelectric energy conversion devices are almost identical to those used in manufacturing microelectronic devices and integrated circuits. 

GaAs, CuInS2, CuInSe2- Semiconductor electrodes have received increasing attention as a consequence of their potential application in photoelectrochemical energy conversion devices. In order to achieve optimum efficiency, the knowledge of the surface composition plays a crucial role. Surface modifications may occur during operation of the photo electrode, or may be the result of a chemical or electrochemical treatment process prior to operation. 

Electrochemical Instrumentation. For the Ru complexes, a 1 cm diameter platinum disk brazed onto a brass holder was used as a working electrode. It was masked with ChemGrip (a teflon based epoxy) except for the upper face. Prior to use, it was polished with 1 micron diamond paste (Buehler) and rinsed with water, acetone and methanol. The working electrode for each Os complex was the uppermost platinum layer of a platinum/carbon layered synthetic microstructure (LSM) (Energy Conversion Devices). The LSM consisted of 200 layer pairs of carbon and platinum whose thicknesses were 24.4 and 17.0 A, respectively and where platinum was the outermost layer. The LSM was placed in 1.0 M H2SO4 and cleaned... 

Proton Exchange Membrane Fuel Cells (PEMFCs) are being considered as a potential alternative energy conversion device for mobile power applications. Since the electrolyte of a PEM fuel cell can function at low temperatures (typically at 80 °C), PEMFCs are unique from the other commercially viable types of fuel cells. Moreover, the electrolyte membrane and other cell components can be manufactured very thin, allowing for high power production to be achieved within a small volume of space. Thus, the combination of small size and fast start-up makes PEMFCs an excellent candidate for use in mobile power applications, such as laptop computers, cell phones, and automobiles. 

Energy Conversion Devices (ECD) of Troy, Michigan has announced a potential breakthrough in solid hydrogen storage. ECD is one of the parent companies of GM Ovonics, patent holder for the nickel metal hydride battery. A hydride, by definition, is a solid material that stores hydrogen. 

NiMH batteries can power an electric vehicle for over 100 miles, but are still several times more expensive than lead-acid. NiMH batteries from Energy Conversion Devices were installed in GM s EVj and S-10 electric pickup truck, doubling the range of each. Chrysler has also used... 

The thermal efficiency of an energy conversion device is defined as the amount of useful energy produced relative to the change in stored chemical energy (commonly referred to as thermal energy) that is released when a fuel is reacted with an oxidant. 

Hydrogen may be the only link between physical energy from renewable sources and chemical energy. It is also the ideal fuel for modem clean energy conversion devices like fuel cells or even hydrogen engines. 

S.R. Ovshinsky, K. Sapru, K. Dec, K. Hong, US Patent 4,431,561 Hydrogen storage materials and method of making same. Energy Conversion Devices, Troy, MI (1984). 

Electrochemical energy conversion devices are pervasive in our daily lives. Batteries, fuel cells and supercapacitors belong to the same family of energy conversion devices. They are all based on the fundamentals of electrochemical thermodynamics and kinetics. All three are needed to service the wide energy requirements of various devices and systems. Neither... 

The first issue can be addressed in two ways a primary ET species which has a large optical absorption cross-section can be chosen or arrays of molecules with large optical absorption cross-sections can be used as "antennas" that will efficiently collect and transport the electronic excitation energy to the primary ET species, in direct analogy to photosynthetic systems. While in the latter case it should be possible to develop systems with more efficient solar photon collection, the number of primary ET species will have to be reduced due to the spatial limitations, which will also reduce the potential electric current that can be produced by the system. Thus, questions related to the detailed molecular architecture of biomimetic solar energy conversion devices will have to address this issue, and it is quite likely that a number of compromises will have to be made before optimal design characteristics are obtained. 

Thus, it appears that several systems have been developed which hold promise as prototypes of biomimetic solar energy conversion devices. And in conjunction with the advances being made in experimental and theoretical methods for investigating molecular excited-state processes, prospects for the development of practical biomimetic devices are now substantially better than they were only a decade ago. 

There is a large, growing family of ionic solids in which certain ions exhibit unusually rapid transport. These materials have come to be known as fast ion conductors (FICs). In some cases, the rapid ion transport is accompanied by appreciable electronic conduction as well. There is tremendous interest in the science and technology of fast ion conductors in view of their potential use as electrodes or electrolyte materials in electrochemical energy conversion devices (Hagenmuller van Gool, 1978 Chandra, 1981 Goodenough, 1984). 

In photo-catalytic and solar energy conversion devices, the absorption of a photon results in the generation of electrons and holes, which, upon separation, can provide an electric potential or trigger chemistry. The efficiency of these devices is frequently determined by the transport of the charges following photo-generation. In particular, for TiC>2-based dye-sensitized solar cells, it has been demonstrated that the efficiency is limited by electron transport through TiC>2 nanoparticles [1]. 

As an energy conversion device, the fuel cell is distinguished from a conventional battery by the fact that the electrodes are invariable and caialytically active. Current is generated by reaction on the electrode... 

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