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Solid-state refrigeration technology has become a promising candidate to replace the traditional low-efficiency and environment-harmful vapor compression refrigeration. However, the narrow temperature region becomes a critical problem which hinders the practical applications of caloric materials to a refrigerator. Here, we report a potential way to solve this problem by combining different caloric effects in one refrigerant. A multiferroic ferromagnetic shape memory alloy Ni45Co5Mn37In13 can exhibit large inverse magnetocaloric effect and elastocaloric effect in adjacent working temperature regions. Thus a broad refrigeration temperature span can be realized in Ni45Co5Mn37In13 alloy by applying magnetic field or external stress at different temperature. Moreover, we propose a potential equipment schematic drawing to achieve it. The system can facilitate the multiferroic materials to produce useful cooling at a much larger temperature range. This combined caloric effect and the concept system proposed in this study would inspire researchers working in this field.

Digital image correlation (DIC) is an effective tool for studying the deformation of tested materials. However, high-gradient strain field (HSF) measurement remains a challenging issue in DIC, because multifold factors have a significant effect on the first correlation calculation step of the original displacement and the exact strain reconstruction in the second post-processing step. In this study, we focus on the second step. The formerly proposed local Hermite has been proven as an accurate and robust method, yet substantial programming work is involved in constructing a Hermite element. To solve this issue, a regularized polynomial smoothing (RPS) method is proposed, which replaces the Hermite function of the polynomial. The RPS applies the same kernel function as the point-wise least-squares (PLS) method for easy implementation. Tikhonov regularization and the generalized cross-validation (GCV) function are also used to decrease unavoidable noise and weaken the dependence on window size. The experiments demonstrate that, in the matched/overmatched case, Tikhonov regularization in RPS can greatly decrease the degree of morbidity caused by ill-posed problems in the PLS method, thereby ensuring smoothness and stability of the solution. Moreover, the influences of window size and polynomial order of both the RPS and PLS are also closely studied. In conclusion, the proposed RPS provides a practical, robust and accurate method for HSF measurement.

Luminescent piezoelectric materials promise a stratagem for controlling the optical process by electric field, which would benefit for future optoelectronic devices. Here, Er3+ doped (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 (BCZT: Er3+) piezoelectric ceramics are prepared to demonstrate the proof of concept. In addition to excellent intrinsic piezoelectricity and ferroelectricity, BCZT: Er3+ ceramics exhibit simultaneously strong green upconversion emissions under excitation of 980 nm. Remarkable photoluminescence (PL) quenching phenomenon as well as significant changes on relative intensities of stark lines are observed under external poling electric field. Furthermore, field dependent piezoelectric constant d33 and photoluminescence quenching ratio show similar variation trend and finally saturate for E > 3.5 kV/mm, which provides a noncontact strategy to monitor the piezoelectric constant d33. The PL quenching triggered by electric field in BCZT: Er3+ ceramics is ascribed to the decreased asymmetry originating from field-induced structural transformation from a significant fraction of the tetragonal phase to rhombohedral phase. Our work would be helpful for expanding the scope of luminescent piezoelectric materials and promising future optoelectronic and optical devices with cross-coupled physical properties.

In this study, gravimetric method and electrochemical impedance spectroscopy combined with atomic force microscopy (AFM) and contact angle measurement were used to study the transport of corrosive medium in waterborne thermosetting and thermoplastic coatings with different structures. Three typical kinds of resin membrane of waterborne coatings (waterborne acrylic, waterborne fluorocarbon, and waterborne epoxy coatings) were analyzed. Results show that the transport of corrosive medium in waterborne thermoplastic coatings and waterborne thermosetting coatings is consistent. The transport in these two kinds of coatings can be divided into three stages. In the first stage, transport is primarily affected by the water concentration in the coating and the medium content is linear with t 1 / 2 , which satisfies the Fick diffusion law. Then, medium transport deviates from Fick diffusion and the medium content reaches saturation over time. During condensation of polymer particles in thermoplastic waterborne acrylic coating and waterborne fluorocarbon coating, the intermolecular diffusion of molecular segments on the particle interface is limited. The presence of microstructural defects leads to limited densification of coating and easier formation of medium channels. The waterborne fluorocarbon coating contains symmetric fluorocarbon bonds, resulting in low surface energy, and the hydrophobic properties result in a slower medium transport rate. During coagulation of the latex particles in the waterborne epoxy coating, the crosslinking and curing reaction of the particle interface greatly reduces the microstructural defects, thereby increasing the compactness and resulting in the slowest medium transmission process.

Solid-state refrigeration technology has become a promising candidate to replace the traditional environment-harmful vapor compression refrigeration. However, the narrow temperature region becomes a critical problem hindering the application of caloric materials to a refrigerator. Here, we report a potential way to solve this problem by combining different caloric effects in one refrigerant. A multiferroic ferromagnetic shape memory alloy Ni45Co5Mn37In13can exhibit large magnetocaloric effect and elastocaloric effect simultaneously. Since the working temperature regions of two caloric effects are adjacent, a broad refrigeration temperature span can be realized in Ni45Co5Mn37In13 alloy by applying magnetic field or external stress at different temperature.

As limited by the capacity of the spent fuel pool (SFP), the last discharged full core will remain in the core for storage for an undetermined period. As a result, an extended refilling mode operation will be expected after the permanent shutdown of a BWR/4. During the extended refilling operation, the SFP, refilling cavity and reactor vessel are all connected. In the early transition phase, the residual heat removal (RHR) system will provide cooling to the reactor core, while the enhanced SFP cooling system will provide cooling to the SFP. While after the transition phase, the enhanced SFP cooling system will provide cooling to both the SFP and reactor core. An evaluation was performed to determine the duration of the transition phase containing both RHR and SFP cooling systems. Furthermore, systematic safety analysis was also performed to ensure the safety of the extended refilling mode operation. In this paper, advanced modeling techniques for RELAP5 and MELCOR were successfully developed to analyze the thermal hydraulic response of the extended storage pool. A postulated loss of cooling accident of the extended storage pool without any emergency mitigation was analyzed by RELAP5 and MELCOR, and good agreement between these two codes was observed. According to the steady state analysis of the extended storage pool, the early transition phase with RHR system cooling to the core will be three days, to assure the maximum water temperature in the core below the technical specification limits. Moreover, an assessment of a LBLOCA with rupture at recirculation line was performed by RELAP5 model. It was indicated that the existing makeup system cannot provide effective makeup coolant to the reactor core, unless the makeup coolant could be directed into the core shroud. It was also demonstrated by RELAP5 simulation that only the core spray can provide effective cooling to the reactor core, even under the worst recirculation line break scenario.

Studies on spintronics have provided solid evidence that the grain boundaries (GBs) in polycrystalline manganite can produce a strong extrinsic magnetoresistance (MR). This type of MR, called Low-field MR (LFMR), is larger than the intrinsic MR and can be triggered over a wide range of temperature. However, the existence of more GBs would bring about the weakening of magnetism and decrease the magnitude of MR simultaneously. Here we show that during annealing the application of electric-current to a representative ferromagnetic manganite perovskite, polycrystalline La 2/3 Sr 1/3 MnO 3 (LSMO), can produce more GBs and improve low-field magnetization, which leads to enhanced MR effect and field-response sensitivity as compared to the traditional-annealed sample. By using static micromagnetic models combined with the theories of spin-polarized intergrain tunneling and charge carrier hopping across domain wall, the observed enhancement of magnetoresistive response in current-annealed LSMO can be well explained.

A spent fuel pool (SFP) is designed as a temporary storage facility for spent fuels before the spent fuels can be shipped away for intermediate storage or reprocessing. Although the likelihood of an SFP cooling accident is extremely low, the SFP event at the Fukushima Daiichi unit 4 demonstrated how confusion and lack of information during the progression of an SFP accident could adversely contribute to emergency response actions. Advanced SFP modeling schemes for both RELAP5 and MELCOR were successfully developed to analyze accidents of SFP. According to the heat load density, an SFP was divided into one high power region for the latest discharged fuel bundles and several regular power regions for other fuel bundles with proper lumping schemes. Particular to the RELAP5 modeling, a 3 × 3 hot channel model was also included in the high power region to calculate the interactive responses between adjacent bundles. Detailed thermal hydraulic responses of regions with different power densities, including the hottest bundle, can all be properly simulated. The detailed thermal hydraulic responses observed include temperature rise and inlet mass fluxes driven by bundles with different power, termination of natural circulation flow by descending water level, and sequential heat up of bundles with different powers. A comparison of the counterpart calculation of a loss-of-cooling accident before fuel degradation with both RELAP5 and MELCOR is also demonstrated, and general consistency between the two codes is observed. The SFP RELAP5 model was further applied to evaluate SFP emergency operation procedures involving makeup and spray mitigation in the event of loss-of-cooling or loss-of-coolant. Moreover, the SFP MELCOR model was also applied to calculate severe accident progression after a loss-of-cooling accident in the SFP. The entire progression calculated by MELCOR successfully demonstrates the capability of MELCOR to calculate the SFP responses covering both thermal hydraulics and severe accident progression during an accident involving both loss-of-cooling and loss-of-coolant accidents.

Functional dependence of magnetoresistance on external magnetic field is of great importance for not only discovering the origin of electrical transport but also tailoring materials for advanced properties in magnetic-field-controlled devices. By utilizing the magnetic domain-rotation model combined with antiphase boundary and charge carrier hopping theories, the formular description of magnetoresistance in magnetite (Fe 3 O 4 ) film has been studied systematically. The calculation shows that the magnetoresistance depends linearly and quadratically on the external magnetic field when the fields are applied parallel and perpendicular to the Fe 3 O 4 film plane, respectively. We give the experimental MR data to verify these theoretical results.

The strain error analysis is greatly concerned recently as digital image correlation (DIC) is used to measure the heterogeneous deformation. This paper focuses on the estimation of random error and under-matched error caused by two strain calculation methods, i.e. the point-wise least squares (PLS) and the regularized polynomial smoothing method (RPS). Two assumptions are put forward on the noise error of the calculated displacement that are: a) it is pure random error without bias and b) in each strain window, it is the independent Gaussian white noise with zero-mean. Based on the assumptions, the random error of displacement and strain is estimated, and the under-matched error of displacement and strain is theoretically analyzed by the aid of Laplacian operator. These two error solutions are verified by some stimulated experiments. Then for the typical kernel function of 3rd order polynomial, a self-adaptive algorithm minimizing the total error is proposed to choose the optimal parameters, i.e. window size and parameter λ . Experiments show that when the original displacement noise conforms to the assumptions strictly, 1) the estimated random error and under-matched error agrees very well with the experimental value, 2) the self-adaptive algorithm can give the optimal parameters in restoring the displacement and strain field, and 3) the estimation of random error and under-matched error is affected by DIC noise greatly, and it is better to use low-pass Gaussian filter before utilizing self-adaptive algorithm.

Wilhelmy plate method measures and calculates dynamic contact angle based on force balance equation of the test plate (or fiber). The equation doesn’t consider the resistance force which may result in a measurement error at high testing speed or for plate with non-negligible thickness. In this work, the influences of two ignored resistance forces, i.e. head resistance force and viscous friction, on dynamic contact angle were investigated both theoretically and experimentally. An auxiliary optical facility was designed and added to the tensiometer in order to get dynamic contact angle by direct optical method to verify the validity of the force balance method’s result. A series of experiments for silicone oils with various viscosities on quartz plates with different thicknesses were done and proved that the two above forces cannot be ignored when Ca got larger or the plate got thicker. A new force balance equation was established, in which the fitting results of both head resistance force coefficient and viscous friction coefficient were nearly constant for all the testing twelve systems. By using new equation, the accuracy of dynamic contact angle testing results were obviously improved especially at high Ca .

In this work, a series of biophysical assays were performed in order to analyze the effects of a novel two-dimensional carbon nano-material graphene oxide (GO) on the conformational changes of myoglobin (Mb). This study, for the first time, reveals the molecular interactions of GO with Mb. The conformation of the protein is obviously affected due to the binding interaction of GO with Mb. GO has high ability in disturbing the secondary of Mb by forming the Mb-GO conjunction. Multi-noncovalent interactions including hydrophobic, hydrogen bonds, van der Waals interactions and electrostatic forces contribute to the formation of Mb-GO conjunction. Our findings also show that the existence of GO can obviously decrease the thermal stability of protein. In addition, molecular modeling was used to analyze the lowest energy binding mode of GO with Mb. Taken together, this work can provide an insight into the biological interaction GO-heme protein in some biological applications.

The transport of nanoparticles in the boundary layer is closely related to particle mixing or deposition. We present an in situ imaging of TiO 2 particle volume fraction near gas stagnation plane in a counterflow flame by recently developed phase-selective laser-induced breakdown spectroscopy technique. The concentration boundary layer is well resolved with a spatial resolution of 10 μm. Together with a numerical analysis of particle transport equation, the roles of convection, diffusion and thermophoresis are discussed. The calculated profile of particle volume fraction agrees well with experimental measurements, which indicates that current model of nanoparticle transport is capable to quantitatively predict the concentration profile in boundary layers. Further study shows that altering thermophoretic velocity shifts the concentration boundary layer but does not change the shape of concentration profile. The decaying slope is mainly controlled by diffusion process that is dependent on particle size.

Given postulated accidents that go beyond the plant design basis, long term passive cooling for the nuclear reactor spent fuel pool is important to demonstrate. Large amount of heat transport with small temperature difference is required. Two-phase thermosyphon loops are suitable for these cases. Flow and heat transfer characteristics of a two-phase thermosyphon loop were numerically investigated using RELAP5 code. Effects of fill charge ratio on the heat transfer were analyzed. The fill charge ratio should be chosen between 30% and 80%, smaller than 30% or larger than 80% will reduce the heat transfer. Based on the analysis of two-phase thermosyphon loops, a complete design of a passive cooling system for the spent fuel pool was proposed. An analysis method for decoupling of the thermo-hydraulics of the water natural circulation in spent fuel pool, two-phase flow of ammonia in thermosyphon loop and air natural circulation in cooling tower was presented. The results indicate that 1528 two-phase thermosyphon loops can passively remove 16 MW decay heat from the spent fuel pool successfully. Finally, the velocity and temperature distributions in the spent fuel pool were numerically simulated using ANSYS FLUENT software. It was proved that natural circulation of water in spent fuel pool can be realized with the present design. The temperature uniformity was fairly well and the maximum water temperature was 81 °C.

Internals are one of key equipment in the nuclear islands of High Temperature gas-cooled Reactor Pebble-bed Module (HTR-PM). Their structural integration is very important to the nuclear safety. Different from the internals in pressurized water reactors, a large number of graphite and carbon components are used in the internals of HTR-PM. These components are connected by dowels and keys with gaps between them to compensate the deformation caused by thermal and irradiation stresses. High installation accuracy of each component is required for the important safety and function related devices installed inside the internals, such as control rod and fuel handling system. Due to the cumulative assembly error of the components and the deformation of the supporting structures, the installation of the graphite and carbon internals is very challenging. Detailed requirements for the examination and installation of the graphite component have been developed and continually optimized for both trial assembly and assembly in the reactor. Research was also carried out for measurement techniques, lifting tools, examination and rapid assessments. The installation of graphite and carbon internals has been successfully completed for both modules. Some major installation results, including the position of the channels and levelness of the graphite components as well as the considerations of their acceptance are introduced in the present paper. The lessons-learned and experience can be applied to the installation of internals in HTRs and other reactors using graphite components, such as molten salt reactor.

A 3D (Three-Dimensional) electrochemical-thermal model has been developed to study internal short circuits in a 1 Ah Li-ion cell, which was inspired by the new findings from the controlled internal short tests. Noteworthy difference of the temperature profiles at the short spot were observed between a Anode–Aluminum (current collector) shorting test and a Anode–Cathode shorting test, with the former showing a temperature spike upon incurring short circuit while the later not. Modeling study reveals that the rapid temperature increase observed in the Anode–Aluminum short was the result of high rate discharge while the following sudden temperature drop was due to the lithium transport limitations in the solid and electrolyte phases. By contrast, in the Anode–Cathode short, such limitations were not observed as the discharge rate was much lower. The results of the present study may help design a safer Li-ion cell through the understanding of a specific internal short circuit.

A new controlled test method has been developed to simulate the occurrence of internal short in Li-ion cells. Two different internal short kinds namely aluminum shorting to anode and cathode shorting to anode has been studied with this test method at several states of charge. Infra-red imaging technique has been adopted to analyze the thermal propagation for both the short kinds. As a comparison, the most commonly adopted nail penetration test was also conducted and analyzed using IR-imaging. The instantaneous rise in temperature referred as temperature spike upon incurring internal short was able to be captured using the IR imaging for the anode–aluminum short kind and the magnitude of such temperature spike was found to be proportional to SOC of the cell.

Density Wave Oscillation (DWO) is one of the most common types of instability in boiling systems. Many experiments were conducted to investigate DWO in various geometry channels during last several decades, but what we always want to know is the stability characteristic of one specific system. In this paper, DWO in narrow rectangular channels which have a cross section of 25 mm × 2 mm and a heated length of 1000 mm are investigated by means of RELAP5/MOD3.3. Then 62 DWO experimental data in two narrow rectangular channels and 60 DWO experimental data in two narrow rectangular channels with a large bypass over 1–10 MPa of pressure, 200–800 kg/m2 s of mass velocity, and 10–50 °C of inlet subcooling conditions are adopted to verify the RELAP5 results. The thermal hydraulic behavior, parametric effect study, and flow instability boundary in narrow rectangular channels are simulated and compared with the experimental results. The errors associated with the predictions are addressed. The density, flow rate and pressure drop characteristics during DWO condition are also analyzed. Compared with experimental flow instability boundary, 90% prediction data for two narrow rectangular channels are between ±20% errors and 85% data for two narrow rectangular channels with a large bypass are between ±20% errors. The error becomes higher under the low pressure with high subcooling, low flow rate condition and high pressure condition. During DWO condition, density, flow rate and pressure drop of the heated channels oscillate periodically; flow rates are different along the channel and the inlet and outlet flow rates oscillate almost in reverse and the non-boiling region pressure drop oscillates out-of-phase with respect to boiling region pressure drop. The results aim to be a contribution to the assessment of the code capability to detect the onset of DWO in narrow rectangular channels. The purpose of the paper is to highlight strengths and weaknesses of the code to simulate DWOs as well as to evaluate carefully the suitable numerical settings necessary to assure a correct prediction of the phenomenon.

The fragmentation of molten drops is the key process in the fuel–coolant interaction (FCIs) which may occur during the course of a severe accident in a light water reactor (LWR). However, the mechanisms of this complicated process cannot be clarified sufficiently by experimental studies due to the rapid reaction. In this paper, a multi-phase thermal hydraulic code with the volume of fluid method (VOF) is developed and the fragmentation process of melt drops triggered by external pressure pulse is numerically analyzed to investigate the mechanism of fragmentation in vapor explosions. The simulation results show that the fragmentation process can be divided into several stages, including vapor film collapse, melt drop-coolant direct contact, formation of high pressure spots, rapid growth of a filament around the molten metal drop, rapid fuel coolant interaction area expansion, breaking up of the filament, and mixing of fragments with water. The calculation results are similar to Ciccarelli and Frost’s (Nucl. Eng. Des., 146, 109–132) experiment data. The simulation results suggest that growth and breaking up of a filament are the essential mechanism of melt tin drop fragmentation. Penetration and evaporation of the water jets, which are assumed as fragmentation mechanism in Kim’s model (Nucl. Sci. Eng., 98, 16–28, 1988), are not observed. In the calculation case, when molten metal density is hypothetically smaller, the water penetration is observed. Besides, the effects of external pressure pulse and molten metal temperature on the growth of filament and the explosion bubble are discussed.

The fuel of HTGR is made of some spherical fuel elements with diameter of 60 mm. The cask of fresh fuel is used to temporarily store and transport such a kind of new spherical fuel elements, and it may drop during transport. The dropping process can be simulated by two ways. The first is the coupled Euler-Lagrange (CEL) method, in which the new fuel elements are taking as fluid and can be considered explicitly. The second is referred to as the equivalent mass method. In the method, the cask and the new fuel are not considered individually, and the mass of the new fuel elements is averagely allocated to the bottom head of the cask. The simulating result shows that the CEL method can describe the flow and inertial effects of the new fuel elements in the dropping process, and the lateral fluid dynamic pressure generated by fuel elements to the cask. The impact effect can be fully considered in the equivalent mass method. Results show that the impact force is stronger and the contact time is shorter than that of the CEL method. Finally, parameters of equivalent fluid in the CEL method are discussed. And the results show that the fluid model is reasonable. In one word, calculation results of the two methods can be combined in structural design, which will give a more reasonable design.

Leak rate calculation is very important for Leak Before Break (LBB) analysis. Helium is used as coolant in high temperature gas-cooled reactor (HTGR). Therefore the flows in the cracks of HTGR vessels and pipes are single phase, which are different from the two phase critical flows in the cracks of water reactors. In the present paper, simple leak rate calculation formulae for compressible laminar and turbulent flows in HTGR cracks are introduced. The velocity and pressure distributions in cracks as well as the leak rates are calculated using the formulae. Numerical simulations are also conducted for compressible laminar, turbulent and critical flows with different crack widths and depths. The results of the numerical simulation and theoretical formulae are compared with experimental data. The comparison shows that both the simple theoretical formulae and the numerical simulation can achieve good results.

An electrochemical thermal model was developed to study the internal short-circuit behavior of a lithium ion cell. The model was used to understand several experimental observations: several short-circuit scenarios possible in a lithium ion cell were simulated and the power generated from each case was calculated. Influence of parameters like the SOC and initial temperature of the cell was studied. Experiments were carried out to verify the predictions made using the model. Some pointers are provided towards design of a safer cell.

The main design and operating parameters for the 10 MW high temperature gas-cooled reactor (HTR-10) primary loop pressure boundary system are introduced in this paper. The component installations and the pneumatic and tightness test are also described, including the objectives and methods. The leakage rate test results are analyzed to show that the results meet the design requirements and have enough safety redundancy.

This article describes the structural design requirements, structural arrangement and structural features of the ceramic and metallic internals of the 10 MW high-temperature gas-cooled reactor-test module (HTR-10). The graphite properties used in the ceramic internals are provided, along with the results of an operating stress analysis of the graphite components and the metallic components. Satisfactory results were obtained for the machining and installation of the ceramic components and the stress analysis of the graphite and metallic components of HTR-10.

A differential scanning calorimeter (DSC) was used to perform a thermal stability study of the LiPF6–EC:EMC electrolyte. The effect of different variables on its thermal stability was evaluated: salt (LiPF6) concentration effect, solvents, EC:EMC ratios, and heating rates. Hermetically sealed and crimped DSC pans were used during the experiments. The results indicate that the salt concentration, solvent concentration, and heating rates play an important role in the thermal stability of the LiPF6–EC:EMC electrolyte.

Automatic mesh generation is one of the most important parts in cims (Computer Integrated Manufacturing System). A method based on mesh grading propagation which automatically produces a triangular mesh in a multiply connected planar region is presented in this paper. Its core part is an algorithm for triangulating convex polygons. Making use of the shrinking polygons of a convex polygon and the mesh grading propagation rules, the algorithm automatically propagates boundary gradings into the interior of the region and generates meshes whose elements are close to the equilateral triangle in linear time, meanwhile sizes of elements between dense meshes and sparse meshes vary smoothly. The algorithm is incorporated with domain decomposition techniques to generate satisfactory quasi-uniform meshes for 2D arbitrary domains. Experiment results show that its running time is linear with both the number of nodes and the number of elements when generating meshes of different mesh densities for the same arbitrary domain.

Conflicting reports exist in the literature concerning the composition of thallium mercury iodide. Solid state synthesis with HgI2 and TlI has been reported to give Tl4HgI6 while synthesis from solution has been reported to give Tl2HgI4. In this report we show that the “orange compound” precipitating from solution is actually a 1:1 mole ratio mixture of Tl4HgI6 and HgI2. Pure Tl4HgI6, which is yellow, can be produced by heating the mixture at 100°C for several days to volatilize HgI2 or more simply, by adding Tl(I) to a solution containing 2:1 KI:K2HgI4 to provide the additional iodide ions needed for Tl4HgI6. Tl4HgI6, unlike Ag2HgI4 and Cu2HgI4, has no sharp thermochromic changes and has no measurable ionic conductivity. This provides another example of the significant role the metal ion plans in determining structure and properties of metal mercury iodide compounds.

The synthesis, characterization, and electrochemical properties of sulfide-based lithium glasses are reviewed. Special attention is given to the recent solid state NMR investigations shedding light on the network structure of these glasses and the role that conformers play in modifying the glass network. Electrochemical measurements show that some of these glasses are potentially useful in miniature and thin-film solid state batteries.

A glass processing method that employs a carbon-coated quartz container was used to study the B2S3 containing glasses i.e. (1−x) B2S3−xLi2S and 0.33[(1−y)B2S3−yP2S5]−0.67Li2S, which are extremely reactive towards quartz at temperatures above 400°C. This technique resulted in transparent glasses with a high Li2S content (0.5⩽x⩽0.75) for the (1−x)B2S3−xLi2S system. The glass forming region for the (1−x) P2S5−xLi2S glass system was expanded from 0.66⩽x⩽0.68 in previous studies to 0.5⩽x⩽0.7. The thermal behavior and the Li+ ionic conductivity of these glasses were analyzed. An exothermal peak was found during the glass transition for some B2S3 containing glasses, and the peak could be converted into a second glass transition by annealing at the peak temperature. The coformer sulfide glasses of the 0.33[(1−y)B2S3−yP2S5]−0.67Li2S system generally exhibited higher Li+ ionic conductivity than that of the single sulfide network former glasses, the room temperature conductivity of the glass with y=0.3 reached the value of 0.141 mS/cm.

Ionically conductive glasses have been synthesized using a 1:1 SiS2Li2S base glass and doping with lithium halides. The quenched glasses were ground to a powder and isostatically pressed into pellets with TiS2 electrodes. Conductivity was measured by complex impedance and the bulk resistance was obtained from an extrapolation of the straight line portion to the real axis. Conductivity of the base glass was 1.2×10−4 S-cm−1 at 25°C and increased several-fold when doped with lithium halide.

The local structure in Li2SSiS2LiIl glasses is investigated by solid state high resolution 6Li, 7Li, and 29Si NMR, using the technique of magic-angle sample spinning (MAS) in conjunction with absolute signal quantitation. Parallel studies of crystallized specimens indicate the presence of a crystalline compound with stoichiometry Li2SiS2, and a second phase with the likely stoichiometry Li4SiS4. Two distinct silicon environmentsare found in the latter phase. The 29Si MAS NMR spectra of crystalline lithium silicon sulfides are readily interpretable in terms of microstructures with differing fractions of non-bridging sulfur atoms attached to Si. In analogy to crystalline silicates, the 29Si resonance is shifted downfield with increasing numbers of non-bridging sulfur atoms, with an overall chemical shift range of ca. 30 ppm. In contrast, the 29Si MAS-NMR spectra of the glasses appear invariant over the entire region of glass formation, although the resolution would be sufficient to discern different distributions of microstructures if they weere present. Furthermore, in striking contrast to the oxide-analog system, no correspondence exists between the chemical shifts of the glasses and those observed in their crystalline counterparts. These highly unusual results suggest that the bonding concepts used to describe the local structures of oxidic glasses cannot be applied for the structural description of chalcogenide glasses, even if they are, as in the present case, stoichiometry-analog. Complementary information is provided by lithium NMR. The use of the rare isotope 6Li instead of 7Li offers the advantage of significantly improved spectroscopic resolution, and thus more accurate chemical shift determinations.

A highly conductive glass with the composition: 0.14SiS 2 −0.09P 2 S 5 −0.47Li 2 S−0.30LiI has been synthesized at ambient pressure and quenching in liquid nitrogen. Its conductivity at 25°C was 2.1 mS/cm using lithium electrodes and exhibited dramatically improved stability towards lithium compared to SiS 2 -Li 2 S-LiI glasses. Glasses were also synthesized incorporating B 2 S 3 or Al 2 S 3 in place of P 2 S 5 in the SiS 2 -Li 2 S glass network. These, too, showed high conductivity and some improvement in stability towards lithium.