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The synthesis and electrochemical lithium‐ion storage behavior of hierarchical MoO2/MoS2/heteroatom‐doped carbon (MoO2/MoS2/HD‐C) ternary hybrid have been studied. This ternary hybrid is composed of ultrafine MoO2 nanowires and single/few‐layer MoS2 encapsulated by heteroatom‐doped carbon, constituting secondary cauliflower‐like microspheres. The synthesis is achieved through the synergistic interplay of a polymer and an ionic liquid as structure‐directing agents and carbon sources, using a solvothermal reaction followed by a simple thermal treatment. In this unique architecture, each component synergistically acts with a specific purpose. The HD‐C matrix with abundant defects and vacancies provides fast electronic conduction as well as interfacial storage, and buffers the volume changes during charging/discharging processes. The ultrasmall dimensions of both MoO2 nanowires and single/few‐layered MoS2 components enable rapid Li+ transport in all directions, which is of great benefit to the reversibility of “conversion” reactions. The hierarchical secondary structures assure the robust stability upon long‐term cycling. The ternary hybrid material exhibits enhanced Li+‐storage performance as well as reversible capacity, rate capability, and cycling stability. A high reversible specific capacity of 1147 mA h g−1 is delivered at 50 mA g−1 together with excellent cycling stability, and 841 mA h g−1 can be retained after 1000 cycles at 500 mA g−1.

In this study we design and construct high-efficiency, low-cost, highly stable, hole-conductor-free, solid-state perovskite solar cells, with TiO2 as the electron transport layer (ETL) and carbon as the hole collection layer, in ambient air. First, uniform, pinhole-free TiO2 films of various thicknesses were deposited on fluorine-doped tin oxide (FTO) electrodes by atomic layer deposition (ALD) technology. Based on these TiO2 films, a series of hole-conductor-free perovskite solar cells (PSCs) with carbon as the counter electrode were fabricated in ambient air, and the effect of thickness of TiO2 compact film on the device performance was investigated in detail. It was found that the performance of PSCs depends on the thickness of the compact layer due to the difference in surface roughness, transmittance, charge transport resistance, electron-hole recombination rate, and the charge lifetime. The best-performance devices based on optimized TiO2 compact film (by 2000 cycles ALD) can achieve power conversion efficiencies (PCEs) of as high as 7.82%. Furthermore, they can maintain over 96% of their initial PCE after 651 h (about 1 month) storage in ambient air, thus exhibiting excellent long-term stability.

aeHierarchical hollow microspheres (HHMSs) constitute a very popular class of materials for use as drugdelivery carriers, photocatalysts and electrode materials in batteries, owing to their large, porous surface area and mechanical integrity during intercalation reactions. Here, we used a template-and additive-free hydrothermal route to prepare an unusually shaped SnO 2 material that comprises a hollow spherical morphology with uniform diameters and very thin petal-like nano-sheets grown perpendicularly on the sphere's surface, resembling a "chestnut cupule". We thoroughly investigated the formation mechanism by 119 Sn Mössbauer spectroscopy, powder X-ray diffraction and X-ray photoelectron spectroscopy. Key to this process is the ultrasonic pre-treatment of an aqueous SnCl 2 solution, followed by Ostwald "inside-out" ripening upon hydrothermal processing. This unique morphology has greatly improved the storage capacity and cycling performance of SnO 2 as an anode material for lithium and sodium ion batteries compared with conventional SnO 2 materials.

A Journal ofCover Picture: J. Li and co-workers HierarchicalT ernary MoO 2 /MoS 2 /Heteroatom-Doped Carbon Hybrid Materials for High-Performance Lithium-Ion Storage