Rechargeable sodium-ion battery based on a cathode of copper hexacyanoferrate

Journal of Solid State Electrochemistry - In this work, the performance of copper (II) hexacyanoferrate(III) (CuHCF) as a cathode material for sodium-ion batteries was studied. The compound was...     

Ring-opening polymerization of lactones by mono(cyclopentadienyl)titanium complexes

Mono(cyclopentadienyl)titanium complexes of the general formula Ti(η⁵-C₅R₅)X₂OR' were designed as structurally well-defined mononuclear initiators for the ring-opening polymerization of four-, six-, and seven-membered lactones. Living pseudo-anionic mechanism with acyl-oxygen cleavage is suggested by various NMR spectroscopic studies as well as the isolation of the mono(insertion) products. The nature of the ancillary ligands lead to significant changes in the polymerization activity and is discussed in terms of electronic and steric effects.     

Cation Co-intercalation in Potassium Copper(II) Hexacyanoferrates

The cation-insertion solid state electrochemistry of a potassium copper(II) hexacyanoferrate in contact with LiClO₄/DMSO, NaPF₆/DMSO, and KPF₆/DMSO electrolytes has been theoretically and experimentally studied using the voltammetry of immobilized particles methodology. Voltammetric data, combined with SEM/EDS analysis permit to determine a K_0.876Cu^II_1.328Fe^III_0.049[Fe^III_0.318Fe^II_0.682(CN)₆] stoichiometry for the synthesized solid. Separation of electronic and ionic contributions to Gibbs energy changes can be made based on cyclic voltammetric and open circuit potential measurements. These parameters can be combined to measure values of the Gibbs energy of cation-independent electron transfer of 7.2±0.4 (K⁺), 7.1±0.5 (Na⁺) kJ mol⁻¹, in close agreement with the expected independence of this parameter on the electrolyte cation. The reduction Fe(III) centers bound to cyano groups exhibit a cation-dependent, essentially Nernstian character which can be described in terms of Na⁺ and K⁺ insertion/deinsertion while in the case of Li⁺ electrolytes there is significant co-cation diffusion. Chronoamperometric data provide estimates of the diffusion coefficients of Na⁺, and K⁺ ions through the solid around 10⁻⁹ cm² s⁻¹.