Iron-Doped Sodium Vanadium Oxyflurophosphate Cathodes for Sodium-Ion Batteries-Electrochemical Characterization and In Situ Measurements of Heat Generation.

Sodium-ion batteries (NaIBs) are increasingly being envisioned for grid-scale energy-storage systems because of cost advantages. However, implementation of this vision has been challenged by the low-energy densities delivered by most NaIB cathodes. Toward addressing this challenge, the authors report the synthesis and characterization of a new iron-doped Na3Fe0.3V1.7O(PO4)2F2 cathode using a novel facile hydrothermal route. The synthesized material was characterized using scanning electron microscopy, X-ray diffraction, and Mössbauer spectroscopy techniques. The obtained discharge capacity in the half-cell configuration lies from 119 to 125 to 130 mA h/g at C/10 while tested using three different electrolyte formulations, dimethyl carbonate-ethylene carbonate (EC)-propylene carbonate (PC), diethyl carbonate-EC, and EC-PC, respectively. The synthesized cathodes were also evaluated in full-cell configurations, which delivered an initial discharge capacity of 80 mA h/g with NaTi2(PO4)3MWCNT as the anode. Ionic diffusivity and interfacial charge transfer kinetics were also evaluated as a function of temperature and sodium concentration, which revealed that electrochemical rate performances in this material were limited by charge-transfer kinetics. To understand the heat generation mechanism of the Na/Na3Fe0.3V1.7O(PO4)2F2 half-cell during charge and discharge processes, an electrochemical isothermal calorimetry measurement was carried out at different current rates for two different temperatures (25 and 45 °C). The results showed that the amount of heat generated was strongly affected by the operating charge/discharge state, C-rate, and temperature. Overall, this work provides a new synthesis route for the development of iron-doped Na3Fe0.3V1.7O(PO4)2F2-based high-performance sodium cathode materials aimed at providing a viable pathway for the development and deployment of large-scale energy-storage based on sodium battery systems.

Electrochemical studies of a high voltage Na4Co3(PO4)2P2O7-MWCNT composite through a selected stable electrolyte.

Cathode materials that operate at high voltages are required to realize the commercialization of high-energy-density sodium-ion batteries. In this study, we prepared different composites of sodium cobalt mixed-phosphate with multiwalled carbon nanotubes (Na4Co3(PO4)2P2O7-MWCNTs) by the sol-gel synthesis technique. The crystal structure and microstructure were characterized by using PXRD, TGA, Raman spectroscopy, SEM and TEM. The electrochemical properties of the Na4Co3(PO4)2P2O7-20 wt% MWCNT composite were explored using two different electrolytes. The composite electrode exhibited excellent cyclability and rate capabilities with the electrolyte composed of 1 M sodium hexafluorophosphate in ethylene carbonate:dimethyl carbonate (EC:DMC). The composite electrode delivered stable discharge capacities of 80 mA h g-1 and 78 mA h g-1 at room and elevated (55 °C) temperatures, respectively. The average discharge voltage was around 4.45 V versus Na+/Na, which corresponded to the Co2+/3+ redox couple. The feasibility of the Na4Co3(PO4)2P2O7 cathode for sodium-ion batteries has been confirmed in real time using a full cell configuration vs. NaTi2(PO4)3-20 wt% MWCNT, and it delivers an initial discharge capacity of 78 mA h g-1 at 0.2C rate.

HLA-E polymorphism and soluble HLA-E plasma levels in chronic hepatitis B patients.

Chronic hepatitis B virus (HBV) infection occurs in association to a deregulation of immune system. Human leukocyte antigen E (HLA-E) is an immune-tolerant nonclassical HLA class I molecule that could be involved in HBV progression. To measure soluble (s) HLA-E in patients with chronic HBV hepatitis (CHB). We tested the potential association of HLA-E*01:01/01:03 A > G gene polymorphism to CHB. Our cohort consisted of 93 Tunisian CHB patients (stratified in CHB with high HBV DNA levels and CHB with low HBV DNA levels) and 245 healthy donors. Plasma sHLA-E was determined using enzyme-linked immunosorbent assay (ELISA). Genotyping was performed using polymerase chain reaction sequence-specific primer. No association between HLA-E*01:01/01:03 A > G polymorphism and HBV DNA levels in CHB patients was found. G/G genotype is less frequent in CHB patients without significance. sHLA-E is significantly enhanced in CHB patients compared with healthy controls (P = 0.0017). Stratification according to HBV DNA levels showed that CHB patients with low HBV DNA levels have higher sHLA-E levels compared with CHB patients with high HBV DNA levels. CHB patients with G/G genotype have enhanced sHLA-E levels compared with other genotypes (P = 0.037). This significant difference is maintained only for CHB women concerning G/G genotypes (P = 0.042). Finally, we reported enhanced sHLA-E in CHB patients with advanced stages of fibrosis (P = 0.032). We demonstrate, for the first time, the association of sHLA-E to CHB. Owing to the positive correlation of HLA-E*01:01/01:03 A > G polymorphism and the association of sHLA-E to advanced fibrosis stages, HLA-E could be a powerful predictor for CHB progression. Further investigations will be required to substantiate HLA-E role as a putative clinical biomarker of CHB.

Oxytocin and bone status in men: analysis of the MINOS cohort.

UNLABELLED: Oxytocin, a neurohypophysial hormone, regulates bone metabolism in animal studies and postmenopausal women. In men, oxytocin is not associated with bone mineral density, bone turnover markers, or prevalent fractures, but weakly negatively with incident fragility fracture requiring further studies. INTRODUCTION: We previously showed that serum oxytocin (OT) level is associated with bone mineral density (BMD) and bone turnover rate in postmenopausal women. The aim of our study was to assess the relationship between circulating OT levels and bone status in men. METHODS: In 552 men aged 50 and older from the MINOS cohort, we measured serum levels of OT. We assessed the association of serum OT levels with BMD (lumbar, femoral neck, total hip), bone turnover markers (BTM) (serum N-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (bone ALP), and C-terminal telopeptide of type I collagen (CTX-I)) and fracture risk. RESULTS: In the univariate analysis, serum OT level was not associated with BMD at any site, BTM levels, or with prevalent or incident fracture. OT was significantly correlated with body mass index (BMI) (r = 0.17, p < 0.001), total or bioavalaible 17ß-estradiol (r = 0.09, p = 0.04 and r = 0.20, p < 0.001, respectively), free testosterone (r = 0.17, p < 0.001), and leptin (r = 0.16, p < 0.001). Multivariate analysis did not show significant relationship between serum OT and BMD. After adjustment for age, BMI, interaction BMI/age, history of fall in the last year, and BMD, OT and prevalent fracture were not associated. By contrast, the same analysis with additional adjustment for prevalent fracture showed a weakly significant negative association between OT and incident fracture, e.g., after adjustment for femoral neck BMD, HR = 0.73, 95 %CI 0.55-0.99, p = 0.04. CONCLUSION: In men, serum OT levels are not associated with BMD, bone turnover rate, or prevalent fractures. The weak negative relationship with fracture risk requires further studies.