Study on lithium ion migration in the composite solid electrolyte for lithium metal batteries

In jüngster Vergangenheit ist die Nachfrage nach erneuerbaren Energiequellen enorm angestiegen. Grund dafür ist zum einen der Mangel an fossilen Brennstoffen, insbesondere Erdöl, zum anderen der voranschreitende Klimawandel, der Großteils durch die Verbrennung dieser fossilen Brennstoffe und durch die einhergehende Umweltverschmutzung verursacht wird. Folglich wird vermehrt im mobilen Anwendungsbereich, beispielsweise bei Elektrogeräten und -fahrzeugen, auf Nachhaltigkeit gesetzt. Es wird von den dort verwendeten Sekundärbatterien erwartet, dass sie nicht nur kostengünstig sind, sondern auch hervorragende elektrochemische Eigenschaften aufweisen, wie eine hohe Energie bzw. Leistungsdichte und eine lange Zyklenstabilität. Aktuelle Forschungen an Lithium-Schwefel- und Lithium-Luft-Batterien weisen zwar eine herausragende spezifische Kapazität auf, diese sind allerdings noch nicht auf dem Entwicklungsstand für die großtechnische Produktion im industriellen Maßstab angelangt. „State of the art“ sind momentan Lithium-Ionen und Metall-Batterien, die womöglich noch die nächsten Jahrzehnte am häufigsten zum Einsatz kommen werden. Gegenwärtig weisen kommerzielle Lithiumionenbatterien, die flüssige Elektrolyte beinhalten (z. B. LP30: 1 M LiPF6, gelöst in EC/DMC 1:1 Volumenanteil), eine hohe Ionenleitfähigkeit (~10 mS cm-1) bei Raumtemperatur und eine mäßige Kapazität (150 Ah kg-1 oder 250Wh kg-1) auf. Dieser Kapazitätsbereich kann beispielsweise kaum die Anforderungen langer Reichweiten bei Elektrofahrzeugen erfüllen. Zudem kann eine starke Beschädigung, die etwa durch einen Autounfall verursacht wird, oder aufgrund einer Überladung der Batterie, zu exothermen Reaktionen führen und dadurch einen Kurzschluss verursachen. Dies kann im schlimmsten Fall zu schwerwiegende Explosion führen. Zudem sind die Fortschritte in diesem Gebiet wegen der Toxizität des Elektrolyts und der Gefahr, die durch das Auslaufen des Elektrolyts besteht, stark limitiert. Angesichts dieser Sicherheitsbedenken bei Batterien auf der Basis von Flüssigelektrolyten nimmt das Interesse an allen Festkörperbatterien rasch zu. Aufgrund der hohen mechanischen Festigkeit des Feststoffelektrolyts kann die Dendritenpenetration reduziert werden. Dadurch kann metallisches Lithium für die Anode verwendet werden, was für Festkörperbatterien mit hohen Kapazitäten von großer Bedeutung ist. Der ideale Festelektrolyt soll eine hohe Ionenleitfähigkeit, eine hohe elektrochemische und chemische Stabilität, sowie ein breites elektrochemisches Fenster aufweisen. Gemäß ihren Hauptbestandteilen (Schwefel, Sauerstoff und Kohlenstoff) werden Feststoffelektrolyte in drei Kategorien unterteilt: Sulfid-, Oxid- und Polymer-Typ. Obwohl die toxischen Sulfid-Feststoffelektrolyten hohe Ionenleitfähigkeiten zeigen, reagieren diese leicht mit den Elektroden und sind nicht feuchtigkeitsbeständig. Dadurch degradieren Elektroden und Elektrolyt leicht, wodurch hochohmsche Zwischenphasen gebildet werden. Im Gegensatz dazu zeigen oxidische und polymere Feststoffelektrolyte eine bemerkenswerte elektrochemische Stabilität gegenüber Elektroden und weisen chemische Stabilität an Luft auf. Deshalb sollte sich die Batterieforschung hauptsächlich auf Oxid-Feststoffelektrolyten und Polymer-Feststoffelektrolyten mit hoher ionischer Leitfähigkeit und kompatiblen Elektrolyt-Elektroden-Zwischenphase konzentrieren. Dementsprechend fokussiert sich diese Arbeit auf Lithium-Metall-Batterien mit Feststoffelektrolyten und Lithium-Anoden. Das Ziel ist es dabei, nicht nur die geeignete Zusammensetzung zwischen Elektrode und Elektrolyt zu untersuchen, sondern auch ein Montageverfahren für sichere Batterien zu entwickeln. Diese Thesis wird dabei in drei Abschnitte untergliedert: Der erste Teil behandelt Granatoxid/Polyethylenoxid-Verbundfeststoffelektrolyt. Der nächste befasst sich mit vernetztem Polymer/Granatoxid-Verbundfeststoffelektrolyt mit integriertem Li+ Salz und der dritte mit einem Eisen-stabilisierten Granat/Polymer-Hybrid-Feststoffelektrolyt. Angesichts hoher Ionenleitfähigkeit, moderater Belastungsfähigkeit und hoher Zyklenstabilität zeigen diese Feststoffelektrolyte ein hohes Entwicklungspotential für praktische Anwendungen mit einer verbesserten Sicherheit gegenüber konventionellen Lithium-Ionen-Batterien

Clinical analysis of vulvar cancer

Background: The purpose of this study is to understand the incidence, related factors, and the prognosis factors in order to avoid risk, proper method of diagnosis and treatment and reduce complications and provide the basis.Methods: 85 Vulvar cancer (VC) patients treated in our hospital from 2002.10 to 2012.10 were collected and analyzed by retrospective comparative methods. SPSS19.0 application software was used for the statistical analysis. The clinical data are analyzed by chi-square and F test statistic methods. P < 0.05 was a significant difference between the judgment standard.Results: During 10 years, we treated 3391 cases of the primary malignant tumors including 85 VC cases; VC was 2.89% (85/3391). The age was between 24～88 years old, mean was 57.09±12.93 yrs. old, variable age of the VC had been juvenescence trend (F=6. 013，P=0.016＜0.05＝). The differences between the urban and rural residential area have some influence to the onset of VC. Rural patients are more than urban patients. By statistical analysis, region distribution in these two groups was remarkably different=4.16，P=0.045＜0.05, but the urban proportion of patients in different years has no difference（χ2=0.080, P=0.777）.Conclusion: The number of cases increased progressively in young age. VC patients were more in rural area than urban. History of malignant tumor and obesity has the positive correlation with VC. High-risk groups should be alert to the possibility of VC. Preoperative diagnosis should be Colposcopic, biopsy in order to improve the accuracy of earlier diagnosis. Vulvar resects have an effect on the healing of the incision. Follow-up rate is low; It is difficult to say statistically survival rate is 5 years

A Crosslinked Polyethyleneglycol Solid Electrolyte Dissolving Lithium Bis(trifluoromethylsulfonyl)imide for Rechargeable Lithium Batteries

Replacing liquid electrolytes with solid ones can provide advantages in safety, and all-solid-state batteries with solid electrolytes are proposed to solve the issue of the formation of lithium dendrites. In this study, a crosslinked polymer composite solid electrolyte was presented, which enabled the construction of lithium batteries with outstanding electrochemical behavior over long-term cycling. The crosslinked polymeric host was synthesized through polymerization of the terminal amines of O,O-bis(2-aminopropyl) polypropylene glycol-blockpolyethylene glycol-block-polypropylene glycol and terminal epoxy groups of bisphenol A diglycidyl ether at 90°C and provided an amorphous matrix for Li⁺ dissolution. This composite solid electrolyte containing Li⁺ salt and garnet filler exhibited high flexibility, which supported the formation of favorable interfaces with the active materials, and possessed enough mechanical strength to suppress the penetration of lithium dendrites. Ionic conductivities higher than 5.0x10⁻⁴ Scm⁻¹ above 45°C were obtained as well as a wide electrochemical stability window (>4.51 V vs. Li/Li⁺) and a high Li⁺ diffusion coefficient (≈16.6x10⁻¹³m² s¯¹). High cycling stability (>500 cycles or 1000 h) was demonstrated

Study of the Lithium Storage Mechanism of N-Doped Carbon-Modified Cu₂S Electrodes for Lithium-Ion Batteries

Owing to their high specific capacity and abundant reserve, Cu$_{x}$S compounds are promising electrode materials for lithium-ion batteries (LIBs). Carbon compositing could stabilize the Cu$_{x}$S structure and repress capacity fading during the electrochemical cycling, but the corresponding Li$^{+}$ storage mechanism and stabilization effect should be further clarified. In this study, nanoscale Cu$_{2}$S was synthesized by CuS co-precipitation and thermal reduction with polyelectrolytes. High-temperature synchrotron radiation diffraction was used to monitor the thermal reduction process. During the first cycle, the conversion mechanism upon lithium storage in the Cu$_{2}$S/carbon was elucidated by operando synchrotron radiation diffraction and in situ X-ray absorption spectroscopy. The N-doped carbon-composited Cu$_{2}$S (Cu$_{2}$S/C) exhibits an initial discharge capacity of 425 mAh g$^{-1}$ at 0.1 A g$^{-1}$, with a higher, long-term capacity of 523 mAh g$^{-1}$ at 0.1 A g$^{-1}$ after 200 cycles; in contrast, the bare CuS electrode exhibits 123 mAh g$^{-1}$ after 200 cycles. Multiple-scan cyclic voltammetry proves that extra Li+ storage can mainly be ascribed to the contribution of the capacitive storage

Understanding the Li-ion storage mechanism in a carbon composited zinc sulfide electrode

Sulfide compounds are interesting conversion electrode materials for Li-ion batteries, due to their high theoretical capacity. However, they suffer from large volumetric changes and fast capacity fading. To overcome these issues, nanosized zinc sulfide (ZnS) modified with polyelectrolytes and graphene (ZnS-C/G) has been synthesized and investigated as an enhanced conversion-alloying anode material. In situ synchrotron X-ray diffraction and X-ray absorption spectroscopy are used to elucidate the Li storage process during the 1st cycle. In addition, the evolution of internal resistance and the corresponding solid electrolyte interphase (SEI) formation during the 1st cycle are discussed based on electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results reveal that the formation of lithiated products and the SEI layer at different voltages can influence Li+ diffusion into the electrode. Moreover, an artificial carbon layer can not only facilitate Li+ transport but also avoid the direct formation of the SEI layer on the surface of active particles. Compared to bare ZnS, the ZnS-C/G electrode shows outstanding rate capability and cycling capacity (571 mA h g−1 after 120 cycles at a specific current of 1.0 A g−1 with a retention rate of 94.4%). The high capacity at elevated current density is ascribed to the contribution of capacitive charge storage

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode

Influence of phase variation of ZnMn2O4ZnMn_{2}O_{4}/carbon electrodes on cycling performances of Li-ion batteries

Due to the high specific capacity and low cost, transition metal oxides (TMOs) exhibit huge potential as anode materials for high-performance Li-ion batteries. This study presents the facile synthesis, structural study and electrochemical investigation of ZnMn$_2$O$_4$/carbon (ZMO/C) electrodes. Stabilization of the redox reaction and functional loading of conductive carbon are employed to improve their reversible Li$^+$ storage performance. In the calcination process with carbon, analyzed via high-temperature X-ray diffraction, the tetragonal ZnMn$_2$O$_4$ undergoes a phase change into MnO/ZnO under an inert atmosphere at around 350 °C, while the initial ZnMn$_2$O$_4$ phase is transformed into Mn$_{2.03}$O$_4$/ZnO composite phases under air. The influences of the calcinating temperature and carbon loading on electrochemical performance are investigated, and the excellent cycling stability of ZMO/C electrodes is ascribed to the stable redox reaction and carbon loading. This strategy has led to particular improvement in the structural/electrochemical stability and long-term Li$^+$ storage for conversion electrodes

The Role of Exosomes in Inflammatory Diseases and Tumor-Related Inflammation

Inflammation plays a decisive role in inducing tumorigenesis, promoting tumor development, tumor invasion and migration. The interaction of cancer cells with their surrounding stromal cells and inflammatory cells further forms an inflammatory tumor microenvironment (TME). The large number of cells present within the TME, such as mesenchymal stem cells (MSCs), macrophages, neutrophils, etc., play different roles in the changing TME. Exosomes, extracellular vesicles released by various types of cells, participate in a variety of inflammatory diseases and tumor-related inflammation. As an important communication medium between cells, exosomes continuously regulate the inflammatory microenvironment. In this review, we focused on the role of exosomes in inflammatory diseases and tumor-related inflammation. In addition, we also summarized the functions of exosomes released by various cells in inflammatory diseases and in the TME during the transformation of inflammatory diseases to tumors. We discussed in depth the potential of exosomes as targets and tools to treat inflammatory diseases and tumor-related inflammation