Nanomaterials in architecture for green energy conversion and/ or storage provide one of the most desirable approaches to alleviate environmental and energy issues. [1][2][3][4] As a result, there is increasing interest in developing high-power anode materials, which can match with the state-of-the-art high-power cathode materials, for next generation high-performance rechargeable Li-ion batteries. [5][6][7] Titanium dioxide is regarded as one of the ideal candidates for high-rate anode materials, owing not only to its structural characteristics and special surface activity, [8][9][10][11] but also to its low cost, safety, and environmental benignity. The lack of open channels in bulk TiO 2 is the main drawback that restricts its capacity and rate capability for reversible lithium insertion and extraction. A reduction in the effective size and construction of open channels in the material are the main strategies currently employed to increase the rate performance. [ 1 , 4 ] The capacity could also be improved by reducing the path length of lithium ion migration and improving electron transport at the surface or in the bulk of the material. [ 10 , 12,13 ] With these strategies, the capacity of ultrafi ne TiO 2 nanocrystals and nanotubes, for example, is signifi cantly enhanced at lower rates. However, their capacity and cycle life deteriorate dramatically at higher rates. [ 9 , 14-17 ] In this respect, signifi cant efforts have recently been made on the fabrication of anatase TiO 2 nanosheets with exposed highly reactive (001) facets. [ 18 -21 ] These TiO 2 nanosheets are shown to be an excellent host structure for lithium insertion and extraction due to the presence of exposed (001) facets and short path along the [001] direction for lithium ion diffusion.Although the anatase framework undergoes insignifi cant structural distortion during lithium insertion and extraction, [ 22 ] the rate of lithium diffusion is still limited by the narrow space of the host Ti-O lattice. Also, strongly caustic NaOH and corrosive HCl or HF are commonly used for the synthesis of TiO 2 nanomaterials. [ 17,18 ] Beyond these, there is still potential danger in the high-temperature and high-pressure process in low boiling point infl ammable solvents. [ 21 ] Therefore, it is highly desirable but challenging to synthesize novel TiO 2 nanostructures as high-rate anode materials through a facile and green route. As an important group of solvents, ionic liquids (ILs), which exhibit unique properties including low volatility, a wide liquid temperature range, good dissolving ability, and designability, have been intensively used in organic synthesis, catalysis, and inorganic nanomaterials synthesis. [23][24][25][26] This inspires us to design a facile ILs-based synthetic system to prepare an attractive framework for high-effi ciency lithium storage.One such framework of TiO 2 active materials is ultrathin 2D nanosheets, which allow ultrafast surface lithium storage due to maximized Li + ion diffusion and electron transport and the elimin...

A two-step method has been popularly adopted to fabricate a perovskite film of planar heterojunction organo-lead halide perovskite solar cells (PSCs). However, this method often generates uncontrollable film morphology with poor coverage. Herein, we report a facile method to improve perovskite film morphology by incorporating a small amount of acetate (CH3COO(-), Ac(-)) salts (NH4Ac, NaAc) as nonhalogen additives in CH3NH3I solution used for immersing PbI2 film, resulting in improved CH3NH3PbI3 film morphology. Under the optimized NH4Ac additive concentration of 10 wt %, the best power conversion efficiency (PCE) reaches 17.02%, which is enhanced by ∼23.2% relative to that of the pristine device without additive, whereas the NaAc additive does not lead to an efficiency enhancement despite the improvement of the CH3NH3PbI3 film morphology. SEM study reveals that NH4Ac and NaAc additives can both effectively improve perovskite film morphology by increasing the surface coverage via diminishing pinholes. The improvement on CH3NH3PbI3 film morphology is beneficial for increasing the optical absorption of perovskite film and improving the interfacial contact at the perovskite/spiro-OMeTAD interface, leading to the increase of short-circuit current and consequently efficiency enhancement of the PSC device for NH4Ac additive only.

Natural integrated carbon architecture cathodes without any additives, which were derived from the bark of plane trees, have highly loaded sulfur of 3.2–4.2 mg cm–2. The as-obtained carbon slice has an integrated architecture with micropore-to-macrospore distribution and a large surface area of 528 m2 g–1. As a result, the integrated carbon–sulfur cathode exhibited an initial discharge capacity of 1159 mA h g–1 at 0.2 A g–1 for a lithium–sulfur battery. Even after 60 cycles, a high specific capacity of 608 mA h g–1 with a high Coulombic efficiency (>98%) was retained, much better than MWCNTs-based electrodes and macropore-destroyed carbon slices.

We present the first report of a new suspension method for obtaining cubic MAPbBr 3 single crystal with a concave surface. The cubic MAPbBr 3 crystal with microconcavity possesses good crystallinity and carrier lifetime. Excellent photoelectric performance was provided by the concavity-based MAPbBr 3 photodetectors because of the good light trapping and shortened carrier pathway. As a result, the concavity-based photodetector exhibits superior responsivity of 62.9 and 5.43 A W −1 and EQE of 1.50 × 10 4 % and 1.30 × 10 3 % under low-power and high-power 520 nm irradiation of 3.67 μW cm −2 and 35.4 mW cm −2 at 3 V, respectively, which are more than 500% higher than those of the plane-based photodetector. In particular, the concavity-based photodetector has an ultrahigh detectivity of 6.5 × 10 12 Jones at ultralow power of 3.67 μW cm −2 , which is 6.5 times higher than that of the planar device.

To obtain bulk cubic CH 3 NH 3 PbI 3 , chlorobenzene was employed to regulate the CH 3 NH 3 PbI 3 γ-butyrolactone solution with high saturated solubility at room temperature and a high yield of crystal at 60 °C. As a result, bulk cubic CH 3 NH 3 PbI 3 single crystal was successfully synthesized for the first time in mixed-solvent method at 60 °C, which is a little higher than the tetragonal-cubic phase inversion temperature.

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A promising strategy is demonstrated for the syntheses of metal organic framework/graphene oxide hybrid films with highly ordered layer-by-layer architecture, and the derived hybrids exhibit remarkable energy storage performances.