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Abstract The hollow mesoporous silicon nanobox dually encapsulated by tin oxide and carbon layers is successfully fabricated and used for anode active material of lithium ion battery. The effects of the double coating layers on the structure, morphology and features of nanocomposite are systematically investigated by transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and galvanostatic charge-discharge tests. The results reveal that hollow mesoporous silicon/tin oxide/carbon nanobox has the adjustable void space and a rationally designed hierarchical structure, which permits the free expansion of Si core without breaking double coating layers and preserves the structural integrity of the electrode during the (de)lithiation processes, as well as significantly enhances the electronic conductivity of anode. As expected, the resultant hollow mesoporous silicon/tin oxide/carbon nanobox exhibits a high reversible capacity up to 1535 mAh g−1 at 0.5 A g−1 after 200 cycles of (dis)charging due to the unique nanostructure. Especially, the as-synthesized nanocomposite exhibits an excellent rate capacity as high as 858 mAh g−1 at 6 A g−1. This rational structure design and innovative approach can be of visible significance for the development of new anode active materials of next-generation lithium-ion battery. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Oriented construction of high-performance mesoporous TiNb 2 O 7 (m-TNO) is important to the design innovation of anode material for next-generation lithium-ion batteries (LIBs) due to the high capacity and long cyclic life of m-TNO. However, the conductivity enhancement of m-TNO and thus accelerating Li+ transfer is still the key point to realize its practical application in LIBs. In this work, a synergistic strategy based on the single-core/dual-shell m-TNO@TiC@NC hierarchical structure is put forward, which is achieved by using m-TNO as host architecture as well as TiC and N-doped carbon layer (NC) as dual-shell layers. The results show that the m-TNO@TiC@NC hierarchical structure can not only provide an integrated conductive network to improve the conductivity of m-TNO, but also can establish a reinforced structure to maintain the anode stability. Besides, it is found that the m-TNO@TiC@NC composite has a high capacity of 328.6 mAh g−1 at 0.5 C after 200 cycles and a high-rate capacity of 186.4 mAh g−1 at 5 C by galvanostatic discharge-charge tests. Therefore, this kind of special single-core/dual-shell structure design can convincingly enhance the conductivity of m-TNO and facilitate the Li+ transfer rate, thus promoting electrochemical performances of LIBs due to the synergistic effect of dual-shell layers. Image 1 • The m-TNO@TiC@NC composite is achieved by using m-TNO as host architecture as well as TiC and NC as dual-shell layers. • The m-TNO@TiC@NC composite shows the single-core/dual-shell hierarchical structure. • The new-type ceramic material TiC is used as conducting layer. • The m-TNO@TiC@NC composite displays good electrochemical performance. [ABSTRACT FROM AUTHOR]

The activated carbon cloth (ACC@TNO) with flexible self-support structure, which is decorated by TiNb 2 O 7 (TNO) nanoparticle, is successfully obtained through hydrothermal reaction and calcination process in high temperature, and is used as the binder-free anode material of lithium ion batteries (LIBs). The morphology characteristic, pore structure properties and the phase structure of the ACC@TNO composites are detailedly studied by the scanning electron microscopy (SEM), Brunauer–Emmett–Teller adsorption/desorption measurement (BET) and X-ray diffraction (XRD). Meanwhile, the electrochemical properties of ACC@TNO composite are further tested by cyclic voltammetry and galvanostatic charge-discharge tests. As a result, the LIBs with ACC@TNO as anode material shows an initial discharge capacity of 356 mAh g−1 and an initial coulombic efficiency (ICE) of 87% at the current density of 0.5 C with the voltage window of 1.0–3.0 V. It also has been found that the reversible capacity can still keep as 290 mAh g−1 with the capacity retention of 81% after 500 cycles. Besides, when the cutoff voltage range is set to 0.01–3.0 V, the reversible capacity can reach 340 mAh g−1. Apparently, this work is of great significance for the exploration of the new anode materials with high performance and long cyclic life in next-generation LIBs. Image 1 • The ACC@TNO composite is obtained by epitaxially growing TNO particles on ACC surface like stab grown on the thorn. • The thiourea is use as a nitrogen source and sulfur source to treat the carbon cloth. • The ACC@TNO composite is binder-free anode material. • The ACC@TNO composite displays good electrochemical performance. [ABSTRACT FROM AUTHOR]