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Three-dimensional hierarchical SnO 2 microspheres were successfully synthesized through a rapid sonochemical reaction followed by a facile solvothermal process. The resultant samples were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM). It was observed that the hierarchical SnO 2 microspheres (∼2.2 μm) consist of nanoparticles (∼23–30 nm). These samples are used to fabricate photoelectrodes for dye-sensitized solar cells (DSSCs). The effects of different samples on the photovoltaic performance were studied based on photocurrent-voltage ( J – V ), intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated voltage spectroscopy (IMVS). It is found that the highest power conversion efficiency of 6.25% has been achieved based on the hierarchical SnO 2 microspheres film photoanode with thickness of ∼13.5 μm, and the corresponding photovoltaic parameters are 14.11 mA cm −2 in short-circuit current density, 803 mV in open-circuit voltage and 0.55 in fill factor, respectively. [ABSTRACT FROM AUTHOR]

Abstract Lithium-ion batteries (LIBs) are considered as a promising power source for electric vehicles and electronic products such as mobile phones, laptops, and tablets. The anode material plays a crucial role in the reliability and safety of LIBs. Among the anode candidates, MLi 2 Ti 6 O 14 (M = 2Na, Sr, Ba, Pb) materials have very good prospects due to their excellent safety, good structure stability, negligible volume change, and suitable voltage plateau of about 1.3–1.4 V (vs. Li0/Li+). However, MLi 2 Ti 6 O 14 materials frequently sustain serious capacity decay at high rate due to the poor electronic and ionic conductivities. Therefore, it is very meaningful to summarize comprehensively and scientifically the advances of this material family from all aspects. The main objective of the review is aimed to summarize various proposed strategies (i.e. material treatment, morphology control, surface modification, and cation doping) and the breakthroughs to enhance the rate capacity and cycling stability of the MLi 2 Ti 6 O 14 materials. The review will provide some insights into the structures and performance issues, which will be helpful for the design and optimization of the MLi 2 Ti 6 O 14 materials. Highlights • Progress of MLi 2 Ti 6 O 14 is summarized in details for the first time. • An understanding on modifying MLi 2 Ti 6 O 14 from various aspects is summarized. • Key strategies for improving the cycling stability of MLi 2 Ti 6 O 14 is discussed. • Strategies in the development of MLi 2 Ti 6 O 14 -based batteries are discussed. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Hybrid materials of CoFeO nanoparticles anchored on graphene prepared by a facile hydrothermal process was developed to be anode material for sodium-ion battery. The hybrid nano-structure of CoFeO/graphene not only could be useful to buffer electrode volume accompanying with Na insertion-extraction, but also could be beneficial to improve electrode electric conductivity and further keep graphene sheet separated to improve ion diffusion rate. Electrochemical measurements showed that the hybrid material anode displayed an excellent performance with a large reversible capacity of 330 mAh g after 75 cycle times and a satisfactory rate capability of 170 mAh g at 1 A g. [ABSTRACT FROM AUTHOR]

Nanocomposites of porous graphene anchored with Sb/SbO x nanoparticles were synthesized through a two-step wet chemical process. SbO x /graphene was initially prepared by refluxing SbCl 3 and graphene oxide in benzyl alcohol. Subsequently, the SbO x nanoparticles were partially reduced by NaBH 4 . The nanocomposites exhibited an enhanced performance for sodium-ion battery with a stable sodium-ion storage capacity of 311.6 mAh g −1 at 50 mA g −1 after 100 cycles and a rate capability of 205.6 mAh g −1 at 800 mA g −1 . Reduction of SbO x by adding moderate amount of NaBH 4 was conducive in improving the nanocomposite's electrochemical performance. The sodium-ion storage capacity of Sb/SbO x /graphene material was 1.4 times higher than that of SbO x /graphene without NaBH 4 and 6.2 times higher than that of Sb/graphene with excessive amount of NaBH 4 . [ABSTRACT FROM AUTHOR]

Low hydrophilicity of graphene is one of the major obstacles for biomaterials application. To create some hydrophilic groups on graphene is addressed this issue. Herein, COOH+ ion implantation modified graphene (COOH+/graphene) and COOH functionalized graphene were designed by physical ion implantation and chemical methods, respectively. The structure and surface properties of COOH+/graphene and COOH functionalized graphene were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurement. Compared with graphene, COOH+/graphene and COOH functionalized graphene revealed improvement of cytocompatibility, including in vitro cell viability and morphology. More importantly, COOH+/graphene exhibited better improvement effects than functionalized graphene. For instance, COOH+/graphene with 1 × 1018 ions/cm2 showed the best cell-viability, proliferation and stretching. This study demonstrated that ion implantation can better improve the cytocompatibility of the graphene. [ABSTRACT FROM AUTHOR]