Electrochemical synthesis of carbon-metal fluoride nanocomposites as cathode materials for lithium batteries

Herein we have demonstrated an electrochemical method for the synthesis of carbon-metal fluoride nanocomposites (CMNFCs). Electrochemical intercalation of transition metal ions into graphite fluoride (CFx) resulted in the formation of CMNFCs. As a proof-of-concept, we have synthesized C-FeF2 and C-NiF2 nanocomposites by the electrochemical intercalation of Fe2+ and Ni2+ into CFx from corresponding non-aqueous electrolytes. The C-FeF2 and C-NiF2 nanocomposites synthesized by this method showed high reversible capacity and cycling stability compared to chemically synthesized analogs as cathode materials for lithium batteries. The reversible capacity of chemically synthesized C-FeF2 is 181 mAh g-1, whereas electrochemically synthesized material is 349 mAh g-1 after 20 cycles. The better cycling performance of electrochemically synthesized C-FeF2 was attributed to the homogeneous distribution of FeF2 nanoparticles within the carbon matrix enabled by the electrochemical intercalation of Fe2+. The electrochemical method described here is emission-free, cost-effective, occurs at room temperature, and extendable to the synthesis of several other CMFNCs. Moreover, it might provide new avenues for the synthesis of advanced functional materials

Meeting Report: The Dallas Consensus Conference on Liver Transplantation for Alcohol Associated Hepatitis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153137/1/lt25681.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153137/2/lt25681_am.pd

Facile synthesis of C–FeF2 nanocomposites from CFx: influence of carbon precursor on reversible lithium storage

Transition metal fluorides are an important class of cathode materials for lithium batteries owing to their high specific energy and safety. However, metal fluorides are electrical insulators, exhibiting slow reaction kinetics with Li. Consequently, metal fluorides can show poor electrochemical performance. Instead, carbon–metal fluoride nanocomposites (CMNFCs) were suggested to enhance electrochemical activity. Chemical synthesis of CMNFCs poses particular challenges due to the poor chemical stability of metal fluorides. Recently, we reported a facile one-step method to synthesize carbon–FeF2 nanocomposites by reacting fluorinated carbon (CFx) with iron pentacarbonyl (Fe(CO)5) at 250 °C. The method resulted in C–FeF2 nanocomposites with improved electrochemical properties. Here, we have synthesized four different C–FeF2 nanocomposites by reacting four different CFx precursors made of petro-coke, carbon black, graphite, and carbon-fibers with Fe(CO)5. Electrochemical performance of all four C–FeF2 nanocomposites was evaluated at 25 °C and 40 °C. It is shown that the nature of CFx has a critical impact on the electrochemical performance of the corresponding C–FeF2 nanocomposites. The C–FeF2 nanocomposites were characterized by using various experimental techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, resistivity measurement, and 57Fe Mössbauer spectroscopy to shed light on the differences in electrochemical behaviour of different C–FeF2 nanocomposites

Assessment of donor quality and risk of graft failure after liver transplantation: The ID2EAL score

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/175403/1/ajt17191.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/175403/2/ajt17191_am.pd

Facile Synthesis of Carbon-Metal Fluoride Nanocomposites for Lithium-Ion Batteries

Metal‐fluoride‐based conversion materials have gained interest as cathode materials for lithium‐ion batteries due to their high theoretical energy densities. However, metal fluorides are electrically insulating and experience large volume changes during the charge and discharge processes. Effective synthesis of carbon–metal fluoride nanocomposites (CMFNCs) with stable morphology is one of the keys to achieve high capacities with sustainable cycle life. A general method for the synthesis of CMFNCs is described here. The redox‐mediated reaction between CFx and metal‐carbonyl precursors at relatively low temperatures leads to the formation of the respective CMFNCs. The reaction mechanism for the formation of CFx‐derived C–FeF2 nanocomposites has been investigated. Also, the synthesis and lithium‐storage properties of C–CoF2 and C–MoF3 nanocomposites are reported. In addition, by changing from CFx to graphite oxide and sulfur‐infused porous carbon, the synthesis of C–FeOx and C–FeS nanocomposites is reported

Ethical review of COVID-19 vaccination requirements for transplant center staff and patients

Transplant centers seeking to increase coronavirus disease 2019 (COVID-19) vaccine coverage may consider requiring vaccination for healthcare workers or for candidates. The authors summarize current data to inform an ethical analysis of the harms, benefits, and individual and societal impact of mandatory vaccination, concluding that vaccine requirements for healthcare workers and transplant candidates are ethically justified by beneficence, net utility, and fiduciary duty to patients and public health. Implementation strategies should mitigate concerns about respect for autonomy and transparency for both groups. We clarify how the same arguments might be applied to related questions of caregiver vaccination, allocation of other healthcare resources, and mandates for non-COVID-19 vaccines. Finally, we call for effort to achieve global equity in vaccination as soon as possible