LiV₃O₈/polytriphenylamine composites are synthesized by a chemical oxidative polymerization process and applied as cathode materials for rechargeable lithium batteries (RLB). The structure, morphology, and electrochemical performances of the composites are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, galvanostatic discharge/charge tests, and electrochemical impedance spectroscopy. It was found that the polytriphenylamine particles were composited with LiV₃O₈ nanorods which acted as a protective barrier against the side reaction of LiV₃O₈, as well as a conductive network to reduce the reaction resistance among the LiV₃O₈ particles. Among the LiV₃O₈/polytriphenylamine composites, the 17 wt % LVO/PTPAn composite showed the largest d₁₀₀ spacing. The electrochemical results showed that the 17 wt % LVO/PTPAn composite maintained a discharge capacity of 271 mAh·g⁻¹ at a current density of 60 mA·g⁻¹, as well as maintaining 236 mAh·g⁻¹ at 240 mA·g⁻¹ after 50 cycles, while the bare LiV₃O₈ sample retained only 169 and 148 mAh·g⁻¹, respectively. Electrochemical impedance spectra (EIS) results implied that the 17 wt % LVO/PTPAn composite demonstrated a decreased charge transfer resistance and increased Li⁺ ion diffusion ability, therefore manifesting better rate capability and cycling performance compared to the bare LiV₃O₈ sample. Full article

Li₃V₂(PO₄)_3−xBr_x/carbon (x = 0.08, 0.14, 0.20, and 0.26) composites as cathode materials for lithium-ion batteries were prepared through partially substituting PO₄³⁻ with Br⁻, via a rheological phase reaction method. The crystal structure and morphology of the as-prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and electrochemical properties were evaluated by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). XRD results reveal that the Li₃V₂(PO₄)_3−xBr_x/carbon composites with solid solution phase are well crystallized and have the same monoclinic structure as the pristine Li₃V₂(PO₄)₃/carbon composite. It is indicated by SEM images that the Li₃V₂(PO₄)_3−xBr_x/carbon composites possess large and irregular particles, with an increasing Br⁻ content. Among the Li₃V₂(PO₄)_3−xBr_x/carbon composites, the Li₃V₂(PO₄)_2.86Br_0.14/carbon composite shows the highest initial discharge capacity of 178.33 mAh·g⁻¹ at the current rate of 30 mA·g⁻¹ in the voltage range of 4.8–3.0 V, and the discharge capacity of 139.66 mAh·g⁻¹ remains after 100 charge/discharge cycles. Even if operated at the current rate of 90 mA·g⁻¹, Li₃V₂(PO₄)_2.86Br_0.14/carbon composite still releases the initial discharge capacity of 156.57 mAh·g⁻¹, and the discharge capacity of 123.3 mAh·g⁻¹ can be maintained after the same number of cycles, which is beyond the discharge capacity and cycleability of the pristine Li₃V₂(PO₄)₃/carbon composite. EIS results imply that the Li₃V₂(PO₄)_2.86Br_0.14/carbon composite demonstrates a decreased charge transfer resistance and preserves a good interfacial compatibility between solid electrode and electrolyte solution, compared with the pristine Li₃V₂(PO₄)₃/carbon composite upon cycling. Full article

Liquid chromatography, coupled with tandem mass spectrometry, has become one of the most popular methods for the analysis of post‐transcriptionally modified transfer ribonucleic acids (tRNAs). Given that the information collected using this platform is entirely determined by the mass of the analyte, it has proven to be the gold standard for accurately assigning nucleobases to the sequence. For the past few decades many labs have worked to improve the analysis, contiguous to instrumentation manufacturers developing faster and more sensitive instruments. With biological discoveries relating to ribonucleic acid happening more frequently, mass spectrometry has been invaluable in helping to understand what is happening at the molecular level. Here we present a brief overview of the methods that have been developed and refined for the analysis of modified tRNAs by liquid chromatography tandem mass spectrometry. Full article