Phase equilibria in quasibinary system ScPO4-Na3PO4 and formation of heterovalent Zr-substituted solid solutions (up to 10 mol%) for Sc3+ in Na3Sc2(PO4)3 complex phosphate were studied by ceramic technique at 1050°C. Obtained samples were investigated with X-ray powder diffraction and impedance spectroscopy. Zr-substituted (10 mol%) Na3Sc2(PO4)3has ionic conductivity of 3.18.10-1 S/cm at 300°C.

Microporous carbon containing little mesoporosity was chemically modified through a vapor phase iodation treatment in an effort to improve the electrochemical performance of activated carbon system commonly utilized in symmetric and asymmetric capacitors. This new carbon system has been studied with respect to their structural, morphological and electrochemical properties and contrasted to the mesoporous carbon based nanocomposites.

Thermal energy storage with phase change materials is one of the most efficient means of storing available energy because of its advantages such as providing higher thermal storage capacity, lower storage temperature, isothermal operation and less storage space. Thermal energy storage property of a new type of PCM heat exchanger was investigated, in which its main body is based on the traditional structure of a shell-and-tube heat exchanger, and is full of PCMs (CaCl2·6H2O) in the tubes. The hot air at the temperature of 40° was selected as a flow medium, and the temperature measurements of the test points were carried out at the inlet and outlet of this kind of PCM heat exchanger. The experimental results showed that this kind of PCM heat exchanger could store thermal energy from the hot fluid by means of PCMs in the tubes. Its prospect in engineering applications such as the recovery and utilizations of industrial afterheat or waste heat etc was also analyzed and forecasted.

Thermal energy storage with phase change materials is one of the most efficient ways of storing available energy because of its advantages such as providing higher heat storage capacity, lower storage temperature, isothermal operation and less storage space. This paper reviews the development and investigations of phase change materials in thermal energy storage systems of various engineering applications. There are many phase change materials that melt and solidify at a wide range of temperatures, making them attractive in a lot of applications. Various categories of phase change materials suitable for thermal energy storage are introduced, and the investigations on their important enhancement techniques are also discussed.

Recent experiments show that nanosized olivine LiFePO4 has different phase transition and solubility behavior than that of larger cathode particles. The possibility of metastable or globally stable amorphous phase in nanosized LiFePO4 particles during delithiation is considered in a diffuse-interface model. At a small enough particle size, a lithiated crystalline phase can undergo amorphization upon charging instead of transforming directly to the delithiated crystalline phase at nanoscale particle sizes.

A novel electrode material for Ni metal hydride batteries, composed of electrochemically synthesized, Ni-rich oxide nanowires, was investigated in this study. The nanowires, grown on Alloy 600 in a high-temperature, high-pressure aqueous electrolyte, are typically 25nm in diameter and 5-10um long. Cyclic voltammetry, with surface enhanced Raman spectroscopy (SERS) suggests that anodic polarization of the wires converts Ni2+ species to Ni3+, present as γ–-NiOOH, the chemical phase involved in the charge/discharge reaction in Ni-MH batteries. The reversibility of the reaction was confirmed via multiple polarization cycles and SEM imaging. In addition, the current density and polarization behavior of the nanowires in 0.01M KOH solution is compared to that of planar NiO and Alloy 600. Results suggest that the nanowires, due to their higher surface area, achieves at least 10 times the current density (for a given apparent area) of the non-nanowire samples.

Monolayer thin films of YbBiPt and YBiPt have been produced with 560 nm and 394 nm thick respectively in house and their thermoelectric properties were measured before and after MeV ion bombardment. The energy of the ions were selected such that the bombarding Si ions stop in the silicon substrate and deposit only electronic energy by ionization in the deposited thin film. The bombardment by 5.0 MeV Si ions at various fluences changed the homogeneity as well as reducing the internal stress in the films thus affecting the thermal, electrical and Seebeck coefficient of thin films. The stoichiometry of the thin films was determined using Rutherford Backscattering Spectrometry, the thickness has been measured using interferometry and the electrical conductivity was measured using Van der Pauw method. Thermal conductivity of the thin films was measured using an in-house built 3ω thermal conductivity measurement system. Using the measured Seebeck coefficient, thermal conductivity and electrical conductivity we calculated the figure of merit (ZT). We will report our findings of change in the measured figure of merit as a function of bombardment fluence.

The advanced space missions need for more power opened the way for advanced nuclear reactors and for alternative power conversion procedures. The most advanced power systems available in space are the fuel cells and nuclear reactors. Both systems manifest low efficiencies for converting the primary energy into electricity and as consequence are requiring high heat dump into space mainly by infrared radiation. The thermo-nuclear power generator also requires a high temperature gas turbine and a mechano-electric generator, finally driving to low conversion efficiencies. The new nano-materials offer the possibility of creating direct energy conversion devices able of achieving high conversion efficiencies up to 99% in the cryogenic versions. The interest for direct conversion of the nuclear energy into electricity appeared in early 1940th, by the invention of the thermo-ionic fission device by Linder. Then a series of patents and scientific papers improved gradually the designs and performances of the devices, up to the actual concepts of beta-voltaic and liquid-electronics. The most intuitive direct conversion device looks mainly like a super mirror- or a heterogeneous super-capacitor. The issues on its operation are related to global conversion efficiencies and the stable operation life-time in high radiation field. There are combinations of nano-structures and actinides assuring both the neutron flux stability, by meeting criticality conditions and the direct conversion or the nuclear energy into electricity. Achieving a high efficiency internal conversion of the nuclear energy into electricity is not enough if it is not completed by a high efficiency power extraction system from the nuclear reactor core into the outside load. The development of the new MEMS devices and micro electronics in the 40 nm technologies provides an excellent background for the production of the electric power harvesting and conversion devices embedded in the fuel. The new nano-structured materials may be produced as radiation energy harvesting tiles that are free of actinides, using them for harvesting the energy of radioactive sources and controlled fusion devices, or may include actinides in their structure achieving critical or sub-critical accelerator driven nuclear reactor assemblies. Another predictable advantage of the nano-structure is the property of self-repairing and self-organizing to compensate the radiation damage and improve the lifetime. Due to direct conversion the power density of the new materials may increase from the actual average of 0.2 kw/cm3 to about 1 kw/mm3 driving to miniaturization of nuclear power sources and reductions of the shield weight. At these dimensions and power densities of few thousands horse power per liter the nuclear power source becomes suitable for mobile applications as powering trains, strategic airplanes, etc. These new developments may drive to the production of high power solid-state compact nuclear battery for space applications, leading to a new development stage.

In April 2007, the Office of Basic Energy Science, United States Department of Energy organized and conducted a Basic Energy Sciences Workshop for Electrical Energy Storage at which basic research needs for capacitive energy storage were considered in detail. This paper is intended to highlight the materials research findings/needs of the workshop and to relate them to the development of high energy density capacitors that can have an energy density approaching that of lead acid batteries, a power density greater than that of lithium ion batteries, and cycle life approaching that of carbon/carbon double-layer capacitors. Capacitors inherently have long cycle life and high power capability so the key issue is how to increase their energy density with minimum sacrifice of their inherent cycle life and power advantages. This requires the development of electrode charge storage materials with an effective high specific capacitance (F/g) and high electronic conductivity. The most promising electrode materials appear to be optimized activated carbons, graphitic carbons, nanotube carbons, and metal oxides. Cells can be assembled that utilize one of these materials in the one electrode and another of the material in the other electrode. Such hybrid cells can operate at 3-4V using organic electrolytes and potentially can have energy densities of 15-25 Wh/kg. Initial research is also underway on solid-state, high energy density devices utilizing high dielectric materials (K>15000) which would operate at very high cell voltage. If such dielectric materials can be developed, these devices may have energy densities approaching those of lithium batteries.