Phosphor-converted white light-emitting diodes (pc-WLEDs) are efficient light sources used in lighting, high-tech displays, and electronic devices. One of the most significant challenges of pc-WLEDs is the thermal quenching, in which the phosphor suffers from emission loss with increasing temperature during high-power LED operation. Here, we report a blue-emitting NaSc(PO):xEu phosphor (λ = 453 nm) that does not exhibit thermal quenching even up to 200 °C. This phenomenon of zero thermal quenching originates from the ability of the phosphor to compensate the emission losses and therefore sustain the luminescence with increasing temperature. The findings are explained by polymorphic modification and possible energy transfer from electron-hole pairs at the thermally activated defect levels to the Eu 5d-band with increasing temperature. Our results could initiate the exploration of phosphors with zero thermal quenching for high-power LED applications.

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Graphene-wrapped lithium-excess layered hybrid materials (Li(2)MnO(3)·LiMO(2), M = Mn, Ni, Co, hereafter abbreviated as LMNCO) have been synthesized and investigated as cathode materials for lithium-ion batteries. Cyclic voltammetry measurement shows a significant reduction of the reaction overpotential in benefit of the graphene conducting framework. The electrochemical impedance spectroscopy results reveal that the graphene can greatly reduce the cell resistance, especially the charge transfer resistance. Our investigation demonstrates that the graphene conducting framework can efficiently alleviate the polarization of pristine LMNCO material leading to an outstanding enhancement in cell performance and cycling stability. The superior electrochemical properties support the fine hybrid structure design by enwrapping active materials in graphene nanosheets for high-capacity and high-rate cathode materials.

A general and efficient hydrothermal strategy combined with a high-temperature carbon-coating technique has been developed for large scale synthesis of self-assembled LiFePO 4 /C nano/microspheres employing the biomass of phytic acid as a novel and eco-friendly phosphorus source. The LiFePO 4 /C nano/microspheres are investigated by SEM, TEM, EDS, XRD, Raman spectroscopy, and electrochemical techniques. A reasonable assembly process of the hierarchical structure is proposed on the basis of time-dependent experimental results. Because of the unique structure, the LiFePO 4 /C nano/microspheres show a high tap density of 1.2 g cm −3 , a high reversible specific capacity of 155 mA h g −1 at 0.1 C, as well as excellent rate capability and cycling performance, exhibiting great potential as superior cathode materials in lithium ion batteries. The approach for the preparation of LiFePO 4 by using PA as the phosphorus source may open new prospects for utilization of biomass to produce high performance cathode materials for lithium ion batteries.