Design of Ti4+-doped Li3V2(PO4)3/C fibers for lithium energy storage

In this work, we propose a facile approach to fabricate Ti⁴⁺-doped Li₃V₂(PO₄)₃/C (abbreviated as C-LVTP) nanofibers using an electrospinning route followed by a high temperature treatment. In this designed nanocomposite, the ultrafine LVTP dots are homogeneously dispersed into one-dimensional carbon nanofibers and the Ti⁴⁺ doping does not destroy the crystal structure of monoclinic Li₃V₂(PO₄)₃. Compared to the undoped Li₃V₂(PO₄)₃/C (abbreviated as C-LVP), the as-fabricated C-LVTP fibers present higher reversible capacity, superior high-rate capability as well as better cyclic property. Especially, the C-LVT_7%P cathode delivers not only high capacities of 187.2 and 160.3 mAh g^?1 at 0.5 and 10 C respectively, but also stable cyclic property with the reversible capacity of 135.8 mAh g^?1 at 20 C following 500-cycle spans. The good battery characteristics of C-LVT_7%P can be mainly ascribed to Ti⁴⁺ doping, which can increase the electrical conductivity and Li⁺ diffusion coefficient.     

Determination of optical and structural properties of lithium silicate ceramics with different ratios of Sm doped

In this study, the synthesis and luminescence characterization of Samarium (Sm³⁺) doped lithium metasilicate (Li₂SiO₃) phosphor ceramic were investigated. It was presented and discussed the results obtained on the luminescence and other optical studies such as X-ray diffraction (XRD), optical absorption and luminescence properties of Li₂SiO₃:Sm³⁺ phosphor ceramic. The Li₂SiO₃ compound was shown a characteristic phase in XRD. The doping in the lithium compound was not having a significant effect on the basic crystal structure of the material. The maximum photoluminescence (PL) emission for Sm³⁺ doped Li₂SiO₃ was observed at 554, 583, 641, 725 nm and bore resemblance to the visible region of the spectrum. The glow curves of all synthesized materials have a complex peak structure after being irradiated with a ⁹⁰Sr–⁹⁰Y beta source. In addition, the peak between 400 and 600 nm was seen in the radioluminescence (RL) spectrum because of a wide peak thought to be caused by silicate.     

Enhance cycling performance of LiMn2O4 cathode by Sr2+ and Cr3+ doping

Spinel LiSr_0·1Cr_0·1Mn_1·8O₄ was synthesised by high temperature solid state method in order to enhance the electrochemical performance. The LiSr_0·1Cr_0·1Mn_1·8O₄ (LSCMO) materials were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical tests. The XRD and SEM studies confirm that LSCMO had spinel crystal structure with a space group of Fd3m, and the particle of LSCMO shows irregular shape. The cyclic voltammetry data illustrated that the heavy current charge–discharge performance of LMO was improved by Sr²⁺ and Cr³⁺ doping. The galvanostatic charge–discharge of LSCMO cathode materials was measured at 1, 5, 10 and 20 C. The results indicated that LSCMO improved the capacity retention.     

Rapid synthesis of garnet-type Li7La3Zr2O12 solid electrolyte with superior electrochemical performance

Li₇La₃Zr₂O₁₂-based garnet-type solid electrolytes are promising candidates for use in all-solid-state lithium batteries (ASSLBs). However, their potential in large-scale commercial applications is largely hindered by the time/energy-consuming and lithium-wasting synthetic method which typically needs a long-duration high temperature solid state reaction process. Herein we invent a fast preparation route that involves a short-period thermal reaction (1100 °C for 10 min) in laboratory muffle furnaces following by conventional hot pressing technique to get almost fully dense (Al, Ga, Ta, Nb)-doped garnet-type electrolytes with high phase purity (>99.9 %). The large and compact grains, low porosity and high phase purities of garnet ceramic electrolytes synthesized in this study ensure superior electrochemical performance. Particularly, Ga-doped cubic Li₇La₃Zr₂O₁₂ shows extremely low E_a values (0.17?0.18 eV) and record-high lithium ionic conductivities (>2 × 10^?3 S cm^-1 at 25 °C).     

A design of experiments investigation into dry separation using a Knelson Concentrator

Enhanced gravity, or centrifugal, separators have revolutionised gold processing over the past decades, significantly increasing the recovery of fine (−100 μm) free gold. One of the main drawbacks of centrifugal gravity concentrators is the large volume of water required (even if it is all recycled). With water becoming an ever increasingly important “commodity”, reducing this is of importance both from an environmental and a monetary point of view. This work investigated operating a laboratory scale Knelson Concentrator with a dry feed and using air as the fluidising medium. The feed used was a synthetic mixture of tungsten and quartz, used to mimic a gold ore. The response surface method and central composite design techniques were used to design the experiments and to model the results, with the experimental variables being the bowl speed (G-Level), air fluidising pressure and the feed rate. The models corresponded well to the experimental results, indicating that for this experimental setup, the optimal conditions were a bowl G-Level of 40 G, a feed rate of 220 g/min and an air fluidising pressure of 8 psi.     

Application of the methylene blue test to cement raw materials

Characterisation of raw materials for Portland cement manufacture by use of the methylene blue adsorption method is discussed. The method is shown to be a simple, convenient ‘rule of thumb’ procedure. It provides a guide to the quantity and type of argillaceous minerals present in a given raw material sample.     

Quantum chemical studies of Li cation binding to polyalkyloxides

A quantum chemical study of the binding of Li⁺ cation to polyalkyloxides has been carried out. The lithium cation interaction with three polyalkyloxides (polyethylene oxide (PEO), polytrimethylene oxide (PTMO), and polypropylene oxide (PPO)) has been investigated using ab initio molecular orbital theory at the HF/6-31G^* level with molecular models for the polymers. Coordination by one to six oxygens was considered. In addition, higher level calculations were carried out using G3(MP2) theory for coordination of Li⁺ by one oxygen. For coordination of lithium by one oxygen, the binding energy ordering is PTMO>PPO>PEO, with PTMO having the largest lithium cation affinity. The same ordering is found for larger coordination numbers with the exception of coordination by six oxygens, where the ordering changes due to the steric interactions.     

Study on Oxygen Isotope Fractionation in RE Oxide Minerals

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