Organic Ionic Plastic Crystals as solid electrolytes for lithium batteries

This research demonstrates the cation and anion transfer of an organic ionic plastic crystal (OIPC), quinuclidinium hexafluorophosphate ([HQ]PF6), in the pure state and mixtures doped with lithium or chloride ions. The pure material and the mixtures show relatively simple thermal behaviors. Powder X-ray diffraction determined a cubic crystal structure, a common feature of OIPCs, in the high-temperature phase of the pure material. Solid-state nuclear resonance spectra of the pure material reveal rotation-assisted ion mobility and the presence of the plastic crystal phase. The ionic conductivity of the mixtures doped with lithium ions and chloride ions increases significantly. Arrhenius conduction behaviors are observed in both the pure material and ion-doped mixtures, with effective activation energies of ∼60–110 kJ mol–1. Ionic conductivity also implies that ions transfer either through the bulk crystal or via grain boundaries. This is the first time that the cation and anion transfer in a quinuclidinium-based OIPC is reported, and the anion (here Cl–) is transferred in plastic crystal systems where solid solutions are likely formed. Different ion conduction behaviors of the pure and doped materials are closely associated with shapes and relative sizes of constituent ions. The results provide useful information to improve the understanding of structure–property relationships in OIPCs.

The MR brain image analysis is used to extract clinical information that improve diagnosis and treatment of disease. Brain tumors are one of the most common brain diseases. Clustering is a process for segmenting and classifying objects. There are many clustering strategies such as the hard clustering scheme and the fuzzy clustering scheme, each of them has its own special characteristics. In this work Fuzzy C-Mean clustering was implemented to segment three abnormal brain MR images, and the performance of it was analyised. This algorithms was applied to cluster the images into different clusters number: 5-9 with different values of membership grade: 0.50-0.90 with steps of 0,05 for each cluster number. The percentage of the unclassified pixels that were produced from implementing FCM algorithm with different configuration was calculated. The minimum values of the objective function of the FCM algorithm for different number of clusters and for different membership grade values were also calculated. The results showed that an optimal number of clusters that corresponds to optimal segmentation error is depending on the slice condition. In this experiment, the optimal cluster number was found to be 6. The fluctuation around this number is affected also by the anatomical structure of the slice. In addition, it can be concluded that the objective function may not be the superior criterion for the judgments of goodness, where it may be a few number of pixels with high uncertainty is the source of high error.

Organic ionic plastic crystal (OIPC) electrolytes are among the key enabling materials for solid-state and higher than ambient temperature lithium batteries. This work overviews some of the parameter studies on the Li|OIPC interface using lithium symmetrical cells as well as the optimisation and performance of Li|OIPC|LiFePO4 cells. The effects of temperature and electrolyte thickness on the cycle performance of the lithium symmetrical cell, particularly with respect to the interfacial and bulk resistances, are demonstrated. Whilst temperature change substantially alters both the interfacial and bulk resistance, changing the electrolyte thickness predominantly changes the bulk resistance only. In addition, an upper limit of the current density is demonstrated, above which irreversible processes related to electrolyte decomposition take place. Here, we demonstrate an excellent discharge capacity attained on LiFePO4|10 mol% LiNTf2-doped [C2mpyr][NTf2]|Li cell, reaching 126 mAh g-1 at 50 °C (when the electrolyte is in its solid form) and 153 mAh g-1 at 80 °C (when the electrolyte is in its liquid form). Most remarkably, at high temperature operation, the capacity retention at long cycles and high current is excellent with only a slight (3%) drop in discharge capacity upon increasing the current from 0.2 C to 0.5 C. These results highlight the real prospects for developing a lithium battery with high temperature performance that easily surpasses that achievable with even the best contemporary lithium-ion technology.

The study was aimed at assessing the genetic variation and relatedness among four Capsicum varieties through electrophoretic separation of their leaf and seed proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Total seed and leaf proteins were extracted and separated on 12% polyacrylamide gels using standard protocols. Distinct polymorphism in electrophoretic banding patterns of seed and leaf proteins was observed in the four Capsicum varieties through a total of thirty-eight (38) polypeptide bands in the seeds and a total of seventeen (17) polypeptide bands in the leaves analyzed. Variation existed not only in the number of bands but also in the intensity of bands in both the leaf and seed samples studied. Sokal and Sneath's coefficient of similarity revealed a generally high level of similarity in the seed protein bands of the four varieties studied ranging from 50% to 100%. It also revealed an average level of similarity in the leaf protein bands of the four varieties of Capsicum studied ranging from 16.7% to 83.3%. A dendrogram constructed based on the Single Linkage Cluster Analysis(SCLA) using the relative mobility values of seed and leaf proteins of the four varieties revealed two major clusters. From the seed, cluster 1 contains (C. annuum var. abbreviatum and C. annuum var. acuminatum), and cluster 2(C. annuum var. grossum, and C.frutescens var.baccatum). Also, two prominent clusters were revealed in the leaf sample, with cluster 1 containing (C. annuum var. abbreviatum, C. annuum var. acuminatum and C.frutescens var.baccatum) and cluster 2(C. annuum var. grossum). Significance of the findings has been discussed. Plant breeders can use the information on variation and relatedness among the Capsicum species for cultivar development in pepper.

A Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes that is self-organized to form an arbitrary topology with the absence of fixed infrastructure or centralized administration .In such environment security has become a main concern to provide confidentiality, authentication, integrity, availability, access control, and non-repudiation. Key management is the main component in MANET security.This paper proposes an efficient and secure distributed group key management scheme. Where, nodes in the network are divided into clusters. Each cluster has a cluster head (CH) and cluster members. Cluster head is responsible for maintaining the group key. It also updates the group key whenever a member joins or leaves the cluster. There-keying process takes place within the cluster only. So the computation and communication cost will be reduced. Another level of security is

In this contribution we report on three recent advances in modularity optimization, namely: 1. The randomized greedy (RG) family of modularity optimization al- gorithms are state-of-the-art graph clustering algorithms which are near optimal, fast, and scalable. 2. The extension of the RG family to multi-level clustering. 3. A new entropy based cluster index which allows the detection of the proper clustering levels and of stable core clusters at each level. Last, but not least, several marketing applications of these algorithms for customer enablement and empowerment are discussed: e.g. the detec- tion of low-level cluster structures from retail purchase data, the analy- sis of the co-usage structure of scientific documents for detecting multi- level category structures for scientific libraries, and the analysis of social groups from the friend relation of social network sites.

Organic ionic plastic crystals (OIPCs) have attracted attention as novel organic solid electrolyte materials, but their insufficient mechanical strength and ionic conductivity have prevented their application. In this study, a lithium salt, lithium bis(fluorosulfonyl)amide (LiFSA), and an inorganic solid electrolyte, Li7La3Zr2O12 (LLZO), were added to an OIPC, N,N-diethylpyrrolidinium bis(fluorosulfonyl)amide ([C2epyr][FSA]). The fabricated organic-inorganic hybrid solid electrolytes were evaluated thermally, mechanically, and electrochemically to reveal which factors affect the properties of the electrolytes. All samples showed excellent thermal stability regardless of LiFSA or LLZO concentration, and they were found to be highly plastic and ion-conductive solids at a wide range of temperatures. It was also revealed that the addition of LLZO raised the nanoindentation stiffness (HIT) of the [C2epyr][FSA]/LiFSA composites. The ionic conductivity of the hybrid electrolytes was higher than that of the pristine OIPC, reaching a value of 2.1 × 10-4 S cm-1 at 25 °C upon addition of appropriate amounts of LiFSA and LLZO. Overall, samples with higher LiFSA concentration and moderate LLZO concentration exhibited higher ionic conductivity. Cyclic voltammetry results showed that the [C2epyr][FSA]/LiFSA/LLZO composites were lithium-ion conductors. These findings indicate that by optimizing the concentrations of lithium salt and LLZO, it would be possible to realize their applications as solid electrolytes.

Probing disorder and dynamics in composite electrolytes of an organic ionic plastic crystal and lithium functionalised acrylic polymer nanoparticles

Protic dialkylammonium-based ionic liquids as promising solid-solid phase change materials for thermal energy storage: Synthesis and thermo-physical characterization

Organic ionic plastic crystals (OIPCs) are a unique class of materials that exhibit a short-range disorder on the molecular level but are ordered at higher length scales. Recent experiments in our group have shown that the OIPC methyl(diethyl)isobutylphosphonium hexafluorophosphate ([P122i4][PF6]) exhibits a high ideal selectivity of 30 with respect to CO2 and N2 at 35 °C. Here, we employ classical molecular dynamics simulations for studying gas uptake in the OIPC [P122i4][PF6] at different temperatures. Both adsorption and absorption of the gases CO2, N2, O2, and CH4 were estimated using a gas/solid interface model. The observed trend in gas uptake was CO2 > CH4 > O2 > N2. The CO2 uptake was found to be dependent on both the OIPC structure and temperature. Owing to phase transitions and intermolecular motions, the solid gets disordered with increasing temperatures. The study finds that such disordering effects can also be caused by interface effects, which can enhance gas absorption. The results qualitatively confirmed that the OIPC can be effective in separating CO2 not only from N2, as per the previous experimental study, but also from O2 and CH4. However, strategies to improve the free volume in the material become important.

There is increasing interest in ionic liquid electrolytes for battery applications due to their potential as safer alternatives to conventional liquid electrolytes. By carefully selecting cations and anions, the physicochemical properties of these salts can be optimised. However, investigation of new cations and anions is still required to achieve the desired electrolyte properties such as high conductivity, electrochemical stability and low corrosivity. Thus, here a new series of room temperature ionic liquids (RTILs) and an organic ionic plastic crystal (OIPC) were synthesized and characterized based on N−ethyl−N−methylpyrrolidinium ([C2mpyr]+) and N−ethyl−N−methyloxazolidinium ([C2moxa]+) cations, paired with 4,5‐dicyano‐2‐(trifluoromethyl)imidazolide ([TDI]−) and 4,5‐dicyano‐2‐(pentafluoroethyl)imidazolide ([PDI]−) anions, forming [C2mpyr][TDI] (OIPC), [C2mpyr][PDI] (IL), [C2moxa][TDI] (IL), and [C2moxa][PDI] (IL). Thermal properties were analysed using DSC and TGA. The plastic phase of the OIPC [C2mpyr][TDI] is wide and spans most electrolyte application temperatures, extending from −40 to 56 °C. All salts exhibit thermal stability above 200 °C. The temperature dependence of the transport properties (viscosity, ionic conductivity, self‐diffusion coefficient) were measured and fitted by the Vogel‐Fulcher‐Tamman (VFT) equation, and the ionicity of the ILs is reported. The electrochemical stability windows of the salts were analysed by CV, and the [C2mpyr]+ cation‐based ILs showed the widest window of ~5 V.

Organic ionic plastic crystals (OIPCs) are an important family of materials that have shown exciting possibilities as solid electrolytes for lithium ion batteries and other electrochemical devices. In this study we demonstrate for the first time that, although the X-ray shows sharp diffraction peaks, both cation and anion clearly exhibit significant ion diffusion in solid phase I. Two phases with ion diffusivities differing by 2 orders of magnitude can be identified. The populations of the cation and anion in both phases are found to be unequal, hinting at the existence of (negatively charged) cation vacancies in the plastic crystal phase and a positively charged grain boundary phase. These interesting properties of ion vacancies and unequal populations of cation and anion are likely to be ubiquitous in other OIPCs, and it is of paramount importance to be aware of these features to correctly understand the structure-property relationships of this important material family.

E 01 Modeling Stellar Collisions in Star Clusters E 02 Fast Modelling of Individual Star Clusters E 03 Star Clusters Surviving Low Star Formation Efficiencies E 04 Extreme Stellar Dynamics: Collisions and Captures in Dense Stellar Clusters E 05 Dense Stellar Systems as Tracers of the Formation and Evolution of Galaxies: Advanced Tools for the Determination of Age and Metallicity of Old Globular Clusters E 06 The Merging and Tidal Destruction of Globular Clusters within Inner Galactic Regions E 07 Galaxy Models with Central Density Cusp E 08 The Formation of Super-Star Clusters E 09 Gravitational Radiation from Black Hole Triple Systems E 10 Structure in the Mass Function of Star Clusters E 11 The 30 Doradus Starburst Cluster: Infrared Luminosity Function and Low-mass IMF in a Spatially Resolved Dense Young Stellar System E 12 Brown Dwarfs from Decaying Accreting Triple Systems E 13 Birth and Evolution of Stars in AGN Disks E 14 Formation and Evolution of Clumpy Tidal Tails Around Globular Clusters E 15 Blue Stragglers in Galactic Globular Clusters: Tracing the Effect of Dynamics on Stellar Evolution E 16 Massive, Dense Star Clusters in the Nuclei of Bulge-less Spiral Galaxies

To deal with the limitation that flat routing can hardly be accustomed to large scale Underwater Sensor Networks (USN), a new clustering routing algorithm Dynamic Layered Clustering Routing (DLCR) is proposed, which can be accustomed to larger scale networks. This algorithm divides the networks into several layers from top to bottom, and selects the nodes which have more remaining energy and shorter distance to sink as the cluster head nodes, thus, clusters communication energy consumption are reduced. In order to avoid the same nodes being elected to be cluster head nodes continuously, a dynamic layered mechanism that the networks are divided into different layers in each circle of data gathering is proposed. The experiment shows that DLCR not only has a better stability, but also reduces the energy consumption and prolongs the lifetime of the whole networks.

Wireless sensor networks (WSNs) are used for various applications, such as habitat monitoring, automation, agriculture, and security. In order to send information from very high number of sensor nodes to the base station, it is necessary and economical to group sensors into clusters to prolong network lifetime. Due to the resource limitation of sensor nodes, the collected information from sensor nodes in the cluster has to be compressed quickly and precisely for transmission. In this paper, we propose a VQ-LBG based approach for cluster formation in WSN. The most distinguishing feature of the proposed method is that both energy efficient cluster formation and fast data compression can be guaranteed. Experiment shows its great improvement over other related methods.