A phosphorus allotrope that has not been observed so far, ring-shaped phosphorus consisting of alternate P and P structural units, has been assembled inside multi-walled carbon nanotube nanoreactors with inner diameters of 5-8 nm by a chemical vapor transport and reaction of red phosphorus at 500 °C. The ring-shaped nanostructures with surrounding graphene walls are stable under ambient conditions. The nanostructures were characterized by high-resolution transmission electron microscopy, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, Raman scattering, attenuated total reflectance Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy.

The morphology and hybridization of nanostructures are crucial to achieve properties for various applications. An in situ grown 3D MoS2 nano-mask has been adopted to control the morphology and hybridization of molybdenum compounds. The in situ generated MoS2 mask on MoO3 nanobelt surfaces allowed us to fabricate a 3D c-MoO2@MoS2 hybrid nanostructure, in which c-MoO2 is a carved MoO2 nanobelt with well distributed hole-pattern. The nano-masks have been controlled by adjusting the alignments of MoS2. The exposed MoO2 surfaces of c-MoO2@MoS2 were further sulphurated to give cw-MoO2@MoS2, in which all surfaces of MoO2 are wrapped by a few layers of MoS2. The structure synergistically enhanced the electrochemical performances of MoO2 and MoS2, especially at high current rates. Reversible capacity of 1418 mAh/g and 295 mAh/g after 115 and 300 cycles are still remained for the cw-MoO2@MoS2 anodes at current rates of 1 A/g and 10 A/g, respectively.

The cycling stability of ring-shaped phosphorus as anodes for lithium-ion batteries is significantly enhanced by the encapsulation of carbon nanotubes.

Ap hosphorus allotrope that has not been observed so far,r ing-shaped phosphorus consisting of alternate P 8 and P 2 structural units,h as been assembled inside multi-walled carbon nanotube nanoreactors with inner diameters of 5-8 nm by achemical vapor transport and reaction of red phosphorus at 500 8 8C. The ring-shaped nanostructures with surrounding graphene walls are stable under ambient conditions.T he nanostructures were characterized by high-resolution transmission electron microscopy, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, Raman scattering, attenuated total reflectance Fourier transform infrared spectroscopy, and X-rayphotoelectron spectroscopy.