Transition metal trifluoroacetates (M = Fe, Co, Mn) as precursors for uniform colloidal metal difluoride and phosphide nanoparticles

HF-Free synthesis of colloidal Cs2ZrF6 and (NH4)2ZrF6 nanocrystals

A solution-phase synthesis of colloidally stable A₂BF₆ nanocrystals is reported for the first time, focusing on A⁺ = Cs⁺, NH₄⁺ and B⁴⁺ = Zr⁴⁺. Handling hypertoxic HF is avoided by using NH₄F and a low-boiling-point alcohol, representing the first synthesis of any A₂BF₆ nanocrystals without HF addition. The chemical incompatability of Zr⁴⁺ with other common fluoride sources is discussed.

A Novel Sugar-Assisted Solvothermal Method for FeF2 Nanomaterial and Its Application in LIBs

Due to its quite high theoretical specific-energy density, FeF₂ nanomaterial is a good candidate for the cathode material of high-energy lithium-ion batteries. The preparation of FeF₂ nanomaterial is very important for its application. At present, the preparation process mostly involves high temperature and an inert atmosphere, which need special or expensive devices. It is very important to seek a low-temperature and mild method, without the need for high temperature and inert atmosphere, for the preparation and following application of FeF₂ nanomaterial. This article reports a novel sugar-assisted solvothermal method in which the FeF₃∙3H₂O precursor is reduced into FeF₂ nanomaterial by carbon derived from the dehydration and condensation of sugar. The obtained FeF₂ nanomaterials are irregular granules of about 30 nm, with inner pores inside each granule. Electrochemical tests show the FeF₂ nanomaterial's potential as a lithium-ion battery cathode material.

Rapid metal speciation of cell culture media using reversed-phase separations and inductively coupled plasma optical emission spectrometry

Cell culture media metal content is critical in mammalian cell growth and monoclonal antibody productivity. The variability in metal concentrations has multiple sources of origin. As such, there is a need to analyze media before, during, and after production. Furthermore, it is not the simple presence of a given metal that can impact processes, but also their chemical form that is, speciation. To a first approximation, it is instructive to simply and quickly ascertain if the metals exist as inorganic (free metal) ions or are part of an organometallic complex (ligated). Here we present a simple workflow involving the capture of ligated metals on a fiber stationary phase with passage of the free ions to an inductively coupled plasma optical emission spectrometry for quantification; the captured species are subsequently eluted for quantification. This first level of speciation (free vs. ligated) can be informative towards sources of contaminant metal species and means to assess bioreactor processes.

Thermal synthesis of conversion-type bismuth fluoride cathodes for high-energy-density Li-ion batteries

Towards enhancement of the energy density of Li-ion batteries, BiF₃ has recently attracted considerable attention as a compelling conversion-type cathode material due to its high theoretical capacity of 302 mAh g^-1, average discharge voltage of ca. 3.0 V vs. Li⁺/Li, the low theoretical volume change of ca. 1.7% upon lithiation, and an intrinsically high oxidative stability. Here we report a facile and scalable synthesis of phase-pure and highly crystalline orthorhombic BiF₃ via thermal decomposition of bismuth(III) trifluoroacetate at T = 300 °C under inert atmosphere. The electrochemical measurements of BiF₃ in both carbonate (LiPF₆-EC/DMC)- and ionic liquid-based (LiFSI-Pyr_1,4TFSI) Li-ion electrolytes demonstrated that ionic liquids improve the cyclic stability of BiF₃. In particular, BiF₃ in 4.3 M LiFSI-Pyr_1,4TFSI shows a high initial capacity of 208 mA g^-1 and capacity retention of ca. 50% over at least 80 cycles at a current density of 30 mA g^-1.

Anisotropic fluoride nanocrystals modulated by facet-specific passivation and their disordered surfaces

Rutile-type fluorides have been proven to be active components in the context of emerging antiferr-omagnetic devices. However, controlled synthesis of low-dimensional, in particular two-dimensional (2D), fluorides in a predictable and deterministic manner remains unrealized because of a lack of efficient anisotropic control, which impedes their further development in reduced dimensions. We report here that altered passivation of {110} growing facets can direct the synthesis of rutile-type fluoride nanocrystals into well-defined zero-dimensional (0D) particulates, one-dimensional (1D) rods and 2D sheets in a colloidal approach. The obtained nanocrystals show positive exchange bias and enhanced magnetic transition temperature from the coexistence of long-range antiferromagnetic order and disordered surface spins, making them strong alternatives for flexible magnetic devices and sensors.