To well address the problems of large volume change and dissolution of Fe3O4 nanomaterials during Li(+) intercalation/extraction, herein we demonstrate a one-step in situ nanospace-confined pyrolysis strategy for robust yolk-shell nanospindles with very sufficient internal void space (VSIVS) for high-rate and long-term lithium ion batteries (LIBs), in which an Fe3O4@Fe3C core@shell nanoparticle is well confined in the compartment of a hollow carbon nanospindle. This particular structure can not only introduce VSIVS to accommodate volume change of Fe3O4 but also afford a dual shell of Fe3C and carbon to restrict Fe3O4 dissolution, thus providing dual roles for greatly improving the capacity retention. As a consequence, Fe3O4@Fe3C-C yolk-shell nanospindles deliver a high reversible capacity of 1128.3 mAh g(-1) at even 500 mA g(-1), excellent high rate capacity (604.8 mAh g(-1) at 2000 mA g(-1)), and prolonged cycling life (maintaining 1120.2 mAh g(-1) at 500 mA g(-1) for 100 cycles) for LIBs, which are much better than those of Fe3O4@C core@shell nanospindles and Fe3O4 nanoparticles. The present Fe3O4@Fe3C-C yolk-shell nanospindles are the most efficient Fe3O4-based anode materials ever reported for LIBs.

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A hierarchical high-performance electrode with nanoacanthine-style polyaniline (PANI) deposited onto a carbon nanofiber/graphene oxide (CNF/GO) template was successfully prepared via an in situ polymerization process. The morphology analysis shows that introducing one-dimensional (1D) CNF could significantly decrease/inhibit the staking of laminated GO to form an open-porous CNF/GO architecture. Followed with in situ facial deposition of PANI, the as-synthesized PANI modified CNF/GO exhibits three-dimensional (3D) hierarchical layered nanoarchitecture, which favors the diffusion of the electrolyte ions into the inner region of active materials. The hierarchical free-standing electrodes were directly fabricated into sandwich structured supercapacitors using 1 M H2SO4 as the electrolyte showing a significant specific capacitance of 450.2 F/g at the voltage scan rate of 10 mV/s. The electrochemical properties of the hierarchical structure can be further improved by a reduction procedure of GO before the deposition of PANI.

Two-dimensional (2D) lateral heterostructures have emerged as a hot topic in the fast evolving field of advanced functional materials , but their fabrication is challenging. The layer-structured WS2 was theoretically demonstrated to be inert to oxidation except for the monolayer, which can be selectively oxidized owing to the simultaneous interaction of oxygen with both sides. Combined with the theoretical calculations, a new method was developed for the successful construction of 2D lateral heterostructures of WS2 /WO3 ⋅H2 O in an ambient environment, based on a simple liquid-phase solution exfoliation. These lateral heterostructures of WS2 /WO3 ⋅H2 O have interesting properties, as indicated by enhanced photocatalytic activity toward the degradation of methyl orange (MO).

Mass production of graphene with low cost and excellent properties is essential for its practical applications in energy, composites, biotechnology, and electronics. Here for the first time we demonstrate that graphite powder can be efficiently exfoliated into monolayered and few-layered nanosheets based on the driving forces originating from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO 2 ). A series of surfactants have been studied, and the experimental results indicate that efficient exfoliation of graphene depends on the suitable surfactant chosen in the SC CO 2 solution system. In this work, polyvinylpyrrolidone (PVP) is confirmed to be an excellent surfactant to play the critical role on exfoliation of graphite, which leads to a high-yield graphene nanosheets (87.7%, ≤3 layers) with concentration of 1.93 mg/mL, large lateral size (up to 5 μm) and low oxidation degree (a C/O ratio of 20.28). And the dispersible graphene can be ink-brushed on A4-size paper to form highly conductive films (2.41 Ω s q −1 ), which confirms that our exfoliation method remains the integrity of the perfect structure in graphene to the largest extent. Further, the exfoliated graphene was used to prepare electrospun graphene-beaded carbon fibers for supercapacitors. The obtained materials deliver a high specific capacitance of 371.25 F/g, which is 71.6% higher than that of the pristine carbon fibers, and exhibit an excellent rate performance. Thus, this strategy utilizing reverse-micelle-induced method for exfoliation of graphite to graphene can pave a way for the green solution-processable production of more two-dimensional (2D) nanosheets, which will have great application potential on electronic, biotechnology, energy, and information storage, etc.