A known history of diabetes and ambient hyperglycaemia were independent predictors for death and morbidity in SARS patients. Metabolic control may improve the prognosis of SARS patients.
Li-rich-layered oxide is considered to be one of the most promising cathode materials for high-energy lithium ion batteries. However, it suffers from poor rate capability, capacity loss, and voltage decay upon cycling that limits its utilization in practical applications. Surface properties of Li-rich-layered oxide play a critical role in the function of batteries. Herein, a novel and successful strategy for synchronous tailoring surface structure and chemical composition of Li-rich-layered oxide is proposed. Poor nickel content on the surface of carbonate precursor is initially prepared by a facile treatment of NH 3 ·H 2 O, which can retain at a certain low amount on the surface in the final lithiated Li-rich-layered oxide after a solid-phase reaction process. Moreover, a phase-gradient outer layer with "layered-coexisting phasespinel" structure toward to the outside surface is self-induced and formed synchronously based on poor nickel surface of the precursor. Electrochemical tests reveal this unique surface enables excellent cycling stability, improved rate capability, and slight voltage decay of cathodes. The finding here sheds light on a universal principle both for masterly tailoring surface structure and chemical composition at the same time for improving electrochemical performance of electrode materials.
Abstract. We prove Hessian comparison theorems, Laplacian comparison theorems and volume comparison theorems of Finsler manifolds under various curvature conditions. As applications, we derive Mckean type theorems for the first eigenvalue of Finsler manifolds, as well as generalize a result on fundamental group due to Milnor to Finsler manifolds.
The controllable morphology and size Li-rich Mn-based layered oxide LiNiCoMnO with micro/nano structure is successfully prepared through a simple coprecipitation route followed by subsequent annealing treatment process. By rationally regulating and controlling the volume ratio of ethylene glycol (EG) in hydroalcoholic solution, the morphology and size of the final products can be reasonably designed and tailored from rod-like to olive-like, and further evolved into shuttle-like with the assistance of surfactant. Further, the structures and electrochemical properties of the Li-rich layered oxide with various morphology and size are systematically investigated. The galvanostatic testing demonstrates that the electrochemical performances of lithium ion batteries (LIBs) are highly dependent on the morphology and size of LiNiCoMnO cathode materials. In particular, the olive-like morphology cathode material with suitable size exhibits much better electrochemical performances compared with the other two cathode materials in terms of initial reversible capacity (297.0 mAh g) and cycle performance (95.4% capacity retention after 100 cycles at 0.5 C), as well as rate capacity (142.8 mAh g at 10 C). The excellent electrochemical performances of the as-prepared materials could be related to the synergistic effect of well-regulated morphology and appropriate size as well as their micro/nano structure.
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