Effect of Particle Size and Pressure on the Transport Properties of the Fast Ion Conductor t‐Li₇SiPS₈

All‐solid‐state batteries promise higher energy and power densities as well as increased safety compared to lithium‐ion batteries by using non‐flammable solid electrolytes and metallic lithium as the anode. Ensuring permanent and close contact between the components and individual particles is crucial for long‐term operation of a solid‐state cell. This study investigates the particle size dependent compression mechanics and ionic conductivity of the mechanically soft thiophosphate solid electrolyte tetragonal Li₇SiPS₈ (t‐LiSiPS) under pressure. The effect of stack and pelletizing pressure is demonstrated as a powerful tool to influence the microstructure and, hence, ionic conductivity of t‐LiSiPS. Heckel analysis for granular powder compression reveals distinct pressure regimes, which differently impact the Li ion conductivity. The pelletizing process is simulated using the discrete element method followed by finite volume analysis to disentangle the effects of pressure‐dependent microstructure evolution from atomistic activation volume effects. Furthermore, it is found that the relative density of a tablet is a weaker descriptor for the sample's impedance compared to the particle size distribution. The multiscale experimental and theoretical study thus captures both atomistic and microstructural effects of pressure on the ionic conductivity, thus emphasizing the importance of microstructure, particle size distribution and pressure control in solid electrolytes

Prise en charge du cancer bien différencié de la thyroïde

The prevalence of thyroid cancer is steadily rising and the fortuitous discovery of a thyroid nodule is a frequent situation for the clinician. The clinical importance is the need to exclude thyroid cancer. In this article we present the initial work up and treatment options for differentiated thyroid cancer. Initial diagnosis is done with a dosage of thyroid stimulating hormone and a fine needle aspiration guided by ultrasonography, which permits classification of the lesion and guides the choice of treatment

Effect of Particle Size and Pressure on the Transport Properties of the Fast Ion Conductor t-Li7SiPS8

All-solid-state batteries promise higher energy and power densities as well as increased safety compared to lithium ion batteries, by using non-flammable solid electrolytes and metallic lithium as the anode. As the liquid electrolyte is replaced by a solid electrolyte, ensuring permanent and close contact between the various components as well as between the individual particles is key for the long-term operation of a solid-state cell. Currently, there are few studies on how a solid-state electrolyte behaves when compressed by external pressure. Here we present a study in which the compression mechanics and ionic conductivity evolution of the fast solid-state conductor Li7SiPS8 were investigated under pressure on two samples with different particle sizes. In operando electrochemical impedance spectroscopy under pressure allows the determination of the activation volume of Li7SiPS8. In addition to the experiments under pressure, we show that the determined ionic conductivity additionally depends on the contact pressure. Furthermore, we simulate pelletizing using the discrete element method followed by finite volume analysis, where the effect of the pressure dependent microstructure can be distinguished from the atomistic effect of the activation volume. We conclude not only that the pelletizing pressure is an important parameter for describing the ionic conductivity of a solid, but also the particle size and morphology as well as the contact pressure during the measurement affect the impedance of a solid tablet. Furthermore, the relative density of a tablet is a weaker descriptor for the sample\u27s impedance, compared to the particle size distribution

Effect of Particle Size and Pressure on the Transport Properties of the Fast Ion Conductor t-Li7SiPS8

All-solid-state batteries promise higher energy and power densities as well as increased safety compared to lithium-ion batteries by using non-flammable solid electrolytes and metallic lithium as the anode. Ensuring permanent and close contact between the components and individual particles is crucial for long-term operation of a solid-state cell. This study investigates the particle size dependent compression mechanics and ionic conductivity of the mechanically soft thiophosphate solid electrolyte tetragonal Li7SiPS8 (t-LiSiPS) under pressure. The effect of stack and pelletizing pressure is demonstrated as a powerful tool to influence the microstructure and, hence, ionic conductivity of t-LiSiPS. Heckel analysis for granular powder compression reveals distinct pressure regimes, which differently impact the Li ion conductivity. The pelletizing process is simulated using the discrete element method followed by finite volume analysis to disentangle the effects of pressure-dependent microstructure evolution from atomistic activation volume effects. Furthermore, it is found that the relative density of a tablet is a weaker descriptor for the sample's impedance compared to the particle size distribution. The multiscale experimental and theoretical study thus captures both atomistic and microstructural effects of pressure on the ionic conductivity, thus emphasizing the importance of microstructure, particle size distribution and pressure control in solid electrolytes

Prophylactic and therapeutic vaccination protects sperm health from Chlamydia muridarum-induced abnormalities

Chlamydia is the most common bacterial sexually transmitted infection worldwide and it is widely acknowledged that controlling the rampant community transmission of this infection requires vaccine development. In this study, for the first time, we elucidate the long-term response to male mouse chlamydial vaccination with chlamydial major outer membrane protein (MOMP) and ISCOMATRIX (IMX) both prophylactically and in a novel therapeutic setting. Vaccination significantly reduced and, in some cases, cleared chlamydial burden from the prostates, epididymides, and testes, which correlates with high IgG and IgA tires in tissues and serum. Important markers of sperm health and fertility were protected including sperm motility and proteins associated with fertility in men. Within splenocytes, expression of IFNγ, TNFα, IL17, IL13, IL10, and TGFβ were changed by both infection and vaccination within CD4 and CD8 T cells and regulatory T cells. Within the testicular tissue, phenotypic and concentration changes were observed in macrophages and T cells (resident and transitory). This revealed some pathogenic phenotypes associated with infection and critically that vaccination allows maintenance of testicular homeostasis, likely by preventing significant influx of CD4 T cells and promoting IL10 production. Finally, we demonstrated the testes contained immature (B220+) B cells and mature (CD138+) Chlamydia-specific plasma cells. Thus, through vaccination, we can maintain the healthy function of the testes, which is vital to protection of male fertility

Instability of the Li7SiPS8 Solid Electrolyte at the Lithium Metal Anode and Interphase Formation

Thiophosphate solid electrolytes containing metalloid ions such as silicon or germanium show a very high lithium-ion conductivity and the potential to enable solid-state batteries (SSBs). While the lithium metal anode (LMA) is necessary to achieve specific energies competitive with liquid lithium-ion batteries (LIBs), it is also well known that most of the metalloid ions used in promising thiophosphate solid electrolytes are reduced in contact with an LMA. This reduction reaction and its products formed at the solid electrolyte|LMA interface can compromise the performance of an SSB due to impedance growth. To study the reduction of these metalloid ions and their impact more closely, we used the recently synthesized Li7SiPS8 as a member of the tetragonal Li10GeP2S12 (LGPS) family. Stripping/plating experiments and the temporal evolution of the impedance of symmetric Li|Li7SiPS8|Li transference cells show a severe increase in cell resistance. We characterize the reduction of Li7SiPS8 after lithium deposition with in situ X-ray photoelectron spectroscopy, time-of-flight secondary-ion mass spectrometry, and solid-state nuclear magnetic resonance spectroscopy. The results indicate a continuous reaction without the formation of elemental silicon. For elucidating the reaction pathways, density functional theory calculations are conducted followed by ab initio molecular dynamics simulations to study the interface evolution at finite temperature. The resulting electronic density of states confirms that no elemental silicon is formed during the decomposition. Our study reveals that Li7SiPS8 cannot be used in direct contact with the LMA, even though it is a promising candidate as both a separator and a catholyte material in SSBs