Developing high-energy-density cathodes with prolonged cycling life is crucial to the continuing success of lithium-ion batteries. In particular, nickel-rich layered LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathodes are receiving growing interest due to their high reversible capacities in the range of 160−200 mAh/g and reduced content of critical and expensive cobalt. Nevertheless, nickel-rich NMC materials still encounter several challenges limiting their long-term cyclability, such as irreversible structural rearrangements, transitionmetal dissolution, high surface reactivity, and parasitic oxidation of organic electrolyte at the surface of delithiated Li 1−z Ni x Mn y Co 1−x−y O 2 at high voltages. Here, we investigate the use of several electrolyte additives that can alleviate capacity fading through the formation of a protective layer passivating the surface of nickel-rich NMC811. Film-forming cathode additives should decompose prior to the solvents and cover the electrode surface with a protection layer which prevents further oxidative decomposition of the electrolyte and minimizes surface side reactions. We find that the addition of 1 vol. % tris(trimethylsilyl)phosphite (TMSPi) in combination with 1 vol. % vinylene carbonate (VC) to a standard electrolyte consisting of 1 M LiPF 6 in ethylene carbonate (EC):dimethyl carbonate (DMC) (1:1 vol.) significantly enhances the capacity retention of NMC811/graphite full cells. Remarkably, a discharge capacity retention of 91% is achieved after 200 cycles at C/3. KEYWORDS: LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathodes, electrolyte additives, tris(trimethylsilyl)phosphite, vinylene carbonate, lithium-ion batteries

No abstract

Osmium(cyclooctadiene)(cyclooctatetraene) is used as a molecular precursor to prepare small and narrowly distributed silica supported nanoparticles upon a mild treatment under H2 (1.1 ± 0.3 nm, ca. 90 atoms). Static volumetric chemisorption combined with HAADF-STEM shows that Os nanoparticles adsorb 1.7 ± 0.1 H and 1.4 ± 0.1 CO per surface atom. These particles present high activity in the hydrogenolysis of alkanes via a dimetallacyclopentane mechanism.

Poly(lactic acid) (PLA) is a biodegradable and biocompatible aliphatic polyester whose lactic acid monomers are derived from renewable resources such as corn and sugar beet. As a thermal plastic it can be processed through compounding and injection. As such, we have developed a microfludic device using PLA aimed at blood dialysis application. To quantify the degradation of PLA, its hydrolysis at different pH value was studied. To study the bioresorbable property of these fabricated devices, its decomposition was tested by morphology observation and weight change measurements after embedding in soil under simulated environmental conditions. Upon contact with a hydrophobic surface, platelets and prothrombin are always activated to attach to the surface, resulting in blood clot. This would block the blood flow through the dialysis channels in the microfluidic device. To improve the hydrophilicity, hence the blood compatibility, chemical grafting of a hydrophilic polymer, poly(ethylene oxide) methacrylate (PEGmA), onto the surface of PLA microfluidic device was carried out and the changes in hydrophilicity was monitored through measuring the water contact angle. Our results indicate that chemical grafting of PEGmA significantly improves the hydrophilicity of the device surface.