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Uniform minor Mn-doped LiFePO 4 /C cathode materials are synthesized and their electrochemical performances are investigated systematically. Via tuning the doping amount of Mn, it is found that the well crystallized LiFePO 4 /C doped with 11000 ppm Mn gives the highest discharge capacity of 165 mAh g −1 at 0.1 C at room temperature. Remarkably, it holds a quite stable cycling performance at 45 °C, with capacity retention of 97.4% after 200 cycles using a high rate of 3.0 C, and its low-temperature (−20 °C) specific capacity maintains at high up to 131.4 mAh g −1 at 0.1 C, higher than that of the majority reports. The higher or lower Mn-doping amount than 11000 ppm is found to have less positive impact on the performance of LiFePO 4 /C. Such phenomenon may be attributed to the negative cooperative effect of Mn doping, which enlarges the crystal space for improving the Li + transfer under low dose due to the large radius of Mn, but increases the charge transfer resistance and declines the performance under high dose owing to its poor intrinsic kinetics. [ABSTRACT FROM AUTHOR]

Modifying titanium dioxide (TiO 2) with graphdiyne (Gry) makes that the absorption range of UV-vis-nIR spectrum expands in visible light area. However, in traditional methods, the two materials are combined by hydrothermal process. In this paper, in-situ synthesis, which monomer directly polymerizes on the surface of TiO 2 instead that polymer and TiO 2 combined by hydrothermal method, is employed to get hybrid materials. In the process, TiO 2 thin film was deposited on the glass slide followed by being enfolded in copper (Cu) foil to initiate polymerization and synthesize Gry on the surface of TiO 2 directly. It turns out that with co-catalyst Platinum (Pt) the efficiency of TiO 2 -Gry with introduction of only 1.9 wt% Gry is 12.6% higher than the efficiency of TiO 2 under same test conditions. The improvement is attributed to band structure of the combined material and efficiency of charge transfer. In this system, Gry acts as an excellent medium for charge transfer, which benefits from its intrinsic property and effective contact with TiO 2 by this synthesis. The work points out a new way to get well-combined platelike photocatalyst on transparent substrate. It gives a promising prospect for practical photocatalysis in the future that the quantity and mass ratio of combined materials can be recorded and modified. • Describing a novel morphology of thin film TiO 2 -Gry. • Accomplishing quantitative analysis between performance and additive amount of Gry. • Making adjustable mass ratio of primary material TiO 2 and additive Gry. [ABSTRACT FROM AUTHOR]

Abstract SnO 2 has attracted growing attention as a promising anode material for next generation of Lithium ion batteries because of its high theoretical capacity (1494 mAh g−1) and low working potential. However, the severe volume change during cycling remains one of the great challenges for its practical application. To overcome the obstacle, we propose to utilize the SnO 2 quantum dots loaded on the sulfur-doped reduced graphene oxides by one-pot synthesis. The SnO 2 quantum dots are uniformly dispersed on the sulfur-doped reduced graphene oxides and retain their tiny sizes during the electrochemical reaction, thus alleviate the volume expansion. Meanwhile, the sulfur-doped reduced graphene oxides introduces many defects and can benefit charge transfer and lithium ion diffusion in the electrode. With the synergetic effect between SnO 2 quantum dots and sulfur-doped reduced graphene oxides, the composite anode material can deliver a specific capacity of 897 mA h g−1 at 100 mA g−1 and maintain 88% of original capacity after over 500 cycles at 500 mA g−1, featuring large lithium ion storage capacity and high stability. Graphical abstract SnO 2 quantum dots anchored on 3D S-doped graphene were fabricated via a facile hydrothermal method, and the synergistic effect between the constituent parts ensured the hybrid structure with large lithium storage capacity and long cycle life. Image 1 Highlights • A facile in situ fabrication method is utilized to construct the nano-micro multi-scaled hybrid networks. • SnO 2 quantum dots can restrain the structure collapse during cycling process. • Sulfur-doping into graphene substrate leads to lower charge transfer impedance and faster lithium ion diffusion. • The synergistic effect between quantum dots and S-doped graphene provide high anode performance. [ABSTRACT FROM AUTHOR]