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Ultra-small Fe 3 O 4 nanocrystals (NCs)/garphene nanosheets (GNSs) composites have been synthesized through a facile gel-like film (GF) assisted method in this work. Fe 3 O 4 NCs with particle size ∼10 nm homogeneously dispersed on 2D GNSs. Profiting from the ultra-small Fe 3 O 4 NCs and GNSs, the composites demonstrate superior long-term and high-rate performance as anode materials for lithium ion batteries. Even at the current density of 5 A g −1 , the reversible capacity still maintains 323.4 mAh g −1 after 700 cycles. This work might enlighten us on exploring preferable strategies to develop advanced metal oxides NCs/GNSs composites anode materials for lithium ion batteries or other energy storage devices. [ABSTRACT FROM AUTHOR]

Li 3 V 2 (PO 4 ) 3 (LVP) nanoparticles were first prepared via a simple sol-gel route, then deposited on graphene oxide nanosheets, and finally a composite of LVP/reduced graphene oxide (LVP/G) was obtained after heat treatment. Scanning electron microscope and transmission electron microscope images demonstrate that LVP nanoparticles are homogenously enwrapped into graphene nanosheets or anchored onto the surface of graphene nanosheets. Compared with pure LVP, LVP/G nanocomposites exhibited better electrochemical performance (118.4 mAhg −1 at 1C, and 112.1 mAhg −1 at 2C after 100 cycles) and higher cycling stability (97% capacity retention after 100 cycles at 1C, and 89.5% after 500 cycles at 20C) as cathode materials for Li ion batteries. The enhanced performance can be attributed to the presence of graphene nanosheets among LVP nanoparticles. Electrochemical impedance spectroscopy indicates that graphene nanosheets significantly improve the electrical conductivity of LVP. The as-prepared LVP/G nanocomposites with superior cycling performance at high-rate have potential applications as cathode materials in Li ion batteries. [ABSTRACT FROM AUTHOR]

Recent years, as a competitive anode material for lithium ion batteries (LIBs), tungsten disulfide (WS 2 ) has attracted significant attention for its high theoretical capacity, abundant resources and low cost, but how to improve the cycle stability and reversible capacity is still an important research subject. In this work, stable metallic WS 2 anchored on carbon fiber cloth was fabricated as flexible anode for LIBs. The transversal displacement of S atoms in WS 2 was induced by incorporation of N atoms, and the stability of metallic phase WS 2 was ensured by the formation of N-W covalent bonds. The results of electrochemical measurement and dynamics analysis demonstrate that the incorporation of metallic phase could not only reduce the initial discharge capacity loss, but also improve the reversible capacity than traditional semi-conducting phase WS 2 . [ABSTRACT FROM AUTHOR]