Current large-scale production of flexible solar devices delivers cells with low efficiency. In this paper we present an alternative path to organic or inorganic thin films. Our cells combine the remarkable surface passivation properties of the silicon heterojunction solar cells design, and the quality of n-type Cz wafers. The cells were manufactured on 50-70 µm-thick wafers. The cells have and efficiency of 17.8-19.2%, open-circuit voltages of 735-742 mV, short-circuit currents of 34.5-35.5 mA/cm2, and fill-factors of 72-75%. The cells are not as flexible as bare wafers. Thin cells are particular sensitive to the additional stress introduced by the busbars and the soldered ribbons. For radiuses of curvature over 8cm the cells efficiency remains the same, for radius equal to 6cm the cell efficiency drops less than 2%, and for radius equal to 4cm the drop is less than 3%. The broken fingers due to smaller bend radius lead to higher series resistance and subsequently lower field-factors.

Development of transparent electrodynamic screens (EDS) printed on ultrathin flexible glass film substrates for retrofitting on solar panels and solar mirrors to perform self cleaning function is reviewed. Large-scale solar plants are generally installed in semi-arid and desert areas where dust layers build up on solar collectors causes major energy-yield loss. Maintaining designed plant capacities requires more than 90% reflectivity for CSP mirrors and 90% transmission efficiency for PV modules; solar collectors must therefore be cleaned at a frequency depending on the rate of dust deposition. Scarcity of water in these regions requires a cleaning method that drastically reduces or eliminates water and the associated labor costs for high efficiency operation of large-scale solar plants. An EDS film consists of rows of interdigitated, transparent conducting parallel electrodes embedded within a flexible ultrathin glass film and an optically clear adhesive film used for retrofitting the film on the surface of solar collectors. When phased voltage pulses activate the electrodes, the dust particles are first electrostatically charged, then repelled and removed from the surface of the solar collectors by Coulomb force, restoring transmission efficiency greater than 90%. The electrodes of EDS are either made from silver nanowire or another conductive transparent material printed on a highly transparent, ultrathin (100-μm thick), flexible borosilicate glass film. Applications of different conducting transparent electrodes and methods of printing are reviewed for optimizing self-cleaning function of solar panels and mirrors.

We report in this study the dissociation conditions for the carbon dioxide hydrate in the presence of additive materials. We measured the hydrate-water-vapor (H-Lw-V) three-phase equilibrium data using the isochoric method. Examples of these phase equilibrium data for the additive materials of 1,3,5-trioxane, 2,5-dihydrofuran, 1,3-dioxolane, and 3,4-dihydro-2H-pyran are presented. The experimental pressure range is from 1.6 to 3.3 MPa, and the concentration of each additive is at 10 wt%. The experimental results indicate that cyclic ethers of 1,3,5-trioxane, 2,5-dihydrofuran, and 1,3-dioxolane promote the formation of carbon dioxide hydrate. Their promotion effects at a given pressure are up to 5 K, 6.9 K, and 4.2 K, respectively, The additive material of 3,4-dihydro-2H-pyran, however, shows the inhibitor behavior. The average inhibition effect is about 1.3 K at a given pressure.

We report a simple and scalable process to synthesize the core–shell nanostructure of MoS2@N-doped carbon nanosheets (MoS2@C), in which polydopamine is coated on the MoS2 surface and then carbonized. Transmission electron microscopy reveals that the as-synthesized MoS2@C possesses a nanoscopic and ultrathin layer of MoS2 sheets with a thin and conformal coating of carbon layers (∼5 nm). The MoS2@C demonstrates a superior electrochemical performance as an anode material for lithium ion batteries compared to exfoliated MoS2 sample. This unique core–shell structure is capable of excellent delivery of Li+ ion in charging–discharging process: a specific capacity as high as 1239 mA h g−1, a high rate of charging-discharging capability even at a high current rate of 10 A g−1 while retaining 597 mA h g−1, and a good cycle stability over 70 cycles at a high current rate of 2 A g−1.

Removing residual moisture in lithium-ion battery electrodes is essential for desired electrochemical performance. In this manuscript, the residual moisture in LiNi0.5Mn0.3Co0.2O2 cathodes produced by conventional solvent-based and aqueous processing is characterized and compared. The electrochemical performance has also been investigated for various residual moisture contents. It has been demonstrated that the residual moisture lowers the first cycle coulombic efficiency, but its effect on short term cycle life is insignificant.

During the activation and charge process, vacancies are generated in the Li2MnO3 component in lithium-rich layered cathode materials. The chemical expansion coefficient tensor associated with oxygen vacancies, lithium vacancies and a Li-O vacancy pair were calculated for Li2-xMnO3-δ. The chemical expansion coefficient was larger for oxygen vacancies than for lithium vacancies in most directions. Additionally, the chemical expansion coefficient for a Li-O vacancy pair was shown to not be a linear sum of the chemical expansion coefficients of the two vacancy types, suggesting that the oxygen vacancies and lithium vacancies in Li2-XMnO3-δ exhibit a coupling effect.

Phase transformation enthalpies are determined using the recently developed measurement technique Thin-Film Calorimetry (TFC), which is based on piezoelectric resonators vibrating in thickness shear mode. They are applicable up to at least 1000 °C. To the best of our knowledge, no comparable TFC systems for such high temperatures exist.

The experimental part is divided into two subsections. The first is addressed to a thermodynamic investigation on piezoelectric langasite crystals (LGS, La3Ga5SiO14) which are the key component of the TFC system. The specific heat capacity is measured on LGS crystals of three different manufacturers. It ranges from about 0.45 J g-1 K-1 at 40 °C to about 0.60 J g-1 K-1 at 1000 °C. Thereby, deviations of up to 5 % between the different crystals are detected. Thermal diffusivity data for Y-cut LGS crystals are determined as well. Here, a constant decrease with temperature is detected ranging from 0.48 mm2 s-1 at room temperature to 0.38 mm2 s-1 at 700 °C.

The second part presents thin-film calorimetric investigation on thin films of the family Li-Ni-Mn-Co-Al-Oxide (NMC/NMCA). These cathode materials are investigated and compared when annealed in ambient air or 0.5 % H2/Ar up to 860 °C. Three stoichiometries are chosen: Li(Ni1/3Mn1/3Co1/3)O2, Li(Ni0.6Mn0.2Co0.2)O2, and Li(Ni0.6Mn0.2Co0.15Al0.05)O2. The samples show three or four phase transformations. In air, the samples crystallize in the range of 250-350 °C. In 0.5 % H2/Ar, the transformations occur at higher temperatures. Especially in air, stoichiometric NMC crystallizes at lower temperatures compared to Ni-rich compositions. Additional doping with Al enhances the thermal stability which shifts all phase transformations to higher temperatures in both atmospheres.

Recently, molybdenum oxide (MoO2) has been found to be a chemically stable and relatively inexpensive material for the application as the anode in a lithium ion battery [1-5]. We believe the use of MoO2 in battery applications has been hindered due to a long, complicated, and multistep synthesis process. We present a simple one-pot hydrothermal technique to synthesize MoO2 nanoparticles directly onto a copper (Cu) substrate.

We believe this is a first report of the synthesis of MoO2 directly onto a Cu substrate, and could lead to the ability to both fabricate other materials in a similar manner as well as depositing MoO2 onto other substrates. This technique can reduce anode production time by eliminating the coating process, and also decrease the total amount of chemicals used when compared to a typical powder synthesis and coating processes. The MoO2 coated Cu electrode was characterized using Raman Spectroscopy, Grazing Incident X-ray Diffraction (GIXRD) and scanning electron microscopy (SEM) techniques to confirm the composition, crystallinity and structure of the synthesized MoO2 nanomaterial.

Multiphysics simulations (COMSOL) of core-shell nanoarchitectures show that they can operate at 3 times the C-rate of micron scale thin film materials while still accessing 90% of an additive free cathode oxide material. A high performance Ge anode DC sputtered onto a Cu nanotube current collector is characterised. Volume expansion of Ge is alleviated and mechanical stability is enhanced due to the Cu nanotubes current collector.

A nanoporous carbon (C) material, functionalized with Cobalt-Oxide/Cobalt (CoO/Co) core-shell nanoparticles (NPs), was structurally and chemically characterized with transmission electron microcopy (TEM) while its electrochemical response for Lithium ion battery (LIB) applications was evaluated as well. The results herein show that the nanoporous C material was uniformly functionalized with the CoO/Co core-shell NPs. Further the NPs were crystalline with fcc-type lattice on the Co2+ oxide shell and hcp-type core of metallic Co0. The electrochemical study was carried out by using galvanostatic charge/discharge cycling at a current density of 1000 mA g−1. The potential of this hybrid material for LIB applications was confirmed and it is attributed to the successful dispersion of the Co2+/ Co0 NPs in the C support.