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Hybrid Li-ion capacitor (LIC) draws more attention as novel energy storage device owing to its high power density and high energy density. Designing three-dimensional electrode materials is beneficial for improving electrochemical performance of LICs. Herein, an improved hydrothermal method combined with an ion-exchange reaction is used to manufacture oxygen vacancies (OVs)-doping TiO 2 (TiO 2-x) nanowires/nanosheets (NWS) on Ti-foil. Then TiCl 4 treatment is performed to form TiO 2-x NWS/nanocrystallines (NWSC). These-obtained hierarchical nanoarchitectures assumes enrich electro-active sites and contact areas, which can improve electron transference and structural stability. The TiO 2-x NWSC is used as binder-free anode for Li-ion battery and achieves high specific capacity (300 mAh g−1 at 0.1 A g−1), excellent rate capability (102 mAh g−1 at 5 A g−1) and long cycle stability (44% after 1000 cycles at 1 A g−1). LICs assembled with a TiO 2-x NWSC anode and an activated carbon cathode have an energy density of 44.2 W h kg−1 at the power density of 150 W kg−1. Therefore, the TiO 2-x NWSC is a potential candidate for high energy and high power electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Bismuth (Bi) is a promising material as the anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its characteristics such as reasonable price and high theoretical volumetric capacity (3800 mAh cm−3). Nevertheless, considerable drawbacks have hindered the practical applications of Bi, including its relatively low electrical conductivity and inevitable volumetric change during the alloying/dealloying processes. To solve these problems, we proposed a novel design: Bi nanoparticles were synthesized via a single-step low-pressure vapor-phase reaction and embedded onto the surfaces of multi-walled carbon nanotubes (MWCNTs). After being vaporized at 650℃ and 10-5 Pa, Bi nanoparticles less than 10 nm were uniformly distributed in the three-dimensional (3D) MWCNT networks to form a Bi/MWNTs composite. In this unique design, the nanostructured Bi can reduce the risk of structural rupture during cycling, and the structure of the MWCMT network is beneficial in shortening the electron/ion transport path. In addition, MWCNTs can improve the overall conductivity of the Bi/MWCNTs composite and prevent particle aggregation, thus improving the cycling stability and rate performance. As an anode material for SIB, the Bi/MWCNTs composite has demonstrated excellent fast charging performance with a reversible capacity of 254 mAh/g at 20 A/g. A capacity of 221 mAh g−1 after cycling at 10 A/g for 8000 cycles has also been achieved for SIB. As an anode material for PIB, the Bi/MWCNTs composite has delivered excellent rate performances with a reversible capacity of 251 mAh/g at 20 A/g. A specific capacity of 270 mAh g−1 after cycling at 1 A g−1 for 5000 cycles has also been achieved for PIB. [ABSTRACT FROM AUTHOR]

Raspberry-like multihollow polymer microspheres were prepared by seeded swelling polymerization and decorated with silver nanoparticles (AgNPs) in the presence of polyvinylpyrrolidone (PVP) which acted as both reducing and stabilizing agent. Formation mechanism of the raspberry-like multihollow microsphere was discussed on the basis of water absorption of sulfonated groups in the seeded swelling polymerization. Effects of weight ratio of sodium 4-vinylbenzenesulfonate to styrene (NaSS/St) of the seed particles, the concentration of PVP and [Ag(NH 3 ) 2 ] + ions on the properties of polymer/Ag nanocomposite microspheres were investigated by microscopic observation, nitrogen adsorption/desorption isotherms, UV–vis absorption spectra, X-ray diffraction patterns and thermogravimetric analysis. The results demonstrated that the raspberry-like multihollow microspheres were successfully fabricated by controlling over the NaSS/St of the seed particles in the seeded swelling polymerization by which the fabrication of hollow structure became simple and convenient. The spherical AgNPs were loaded on the polymer microsphere by in-situ chemical reduction due to the stabilization and reduction of PVP and the attraction between sulfonated groups and [Ag(NH 3 ) 2 ] + ions. The raspberry-like multihollow polymer/Ag microspheres showed good catalytic activity and reusability in the degradation of methylene blue in the presence of NaBH 4 . [ABSTRACT FROM AUTHOR]

Multi-hollow particles have drawn extensive research interest due to their high specific areas and abundant inner voids, whereas their convenient synthesis still remains challenging. In this paper, we report a simple and convenient method based on seeded swelling polymerization to prepare the multi-hollow microspheres with enclosed surfaces and compartmentalized voids using monodisperse poly (styrene- co -sodium 4-vinylbenzenesulfonate) microspheres as seed particles. A formation mechanism of the multi-hollow structure was proposed involving the processes of water absorption, coalescence and stabilization of water domains, immobilization of multi-hollow structure, and coverage of surface dimples. The influencing parameters on the morphology of the microspheres, including weight ratio of sodium 4-vinylbenzenesulfonate to styrene in the seed particles, dosage of the swelling monomer and the crosslinking agent were systematically investigated. The internal structure of the resultant microspheres could be tuned from solid to multi-hollow by controlling over these parameters. Multi-hollow microspheres with compartmentalized chambers, smooth surfaces and narrow size distributions were obtained as a result. [ABSTRACT FROM AUTHOR]