Facile Synthesis and High Rate Capability of Silicon Carbonitride/Boron Nitride Composite with a Sheet-Like Morphology

Abstract

International audienceWe report synthesis of a sheet-like composite composed of hexagonal boron nitride (or BN) chemically integrated with silicon carbonitride (SiCN) matrix via a simple pyrolysis route. The composite offers several unique features such as improved electrical conductivity, high-temperature oxidation resistance (at 1000 degrees C), and high electrochemical activity toward Li-ions generally not observed in SiCN or boron-doped SiCN. Tested as electrode in Li-ion half-cell, SiCN/BN show charge capacity of similar to 517 mAh g(-1) at 100 mA g(-1) and 283 mAh g(-1) at 2400 mA g(-1) with respect to total weight of electrode. Additionally, a stable charge capacity of similar to 401 mAh g(-1) at 100 mA g(-1) is retained even after continuous operation for 1000 cycles at 1600 mA g(-1). Chemical characterization of the composite suggests that addition of BN to polysilazane in moderate amounts (similar to 10 wt %) and subsequent pyrolysis resulted in an increased free-carbon content in the amorphous SiCN phase, which exceeded the percolation limit, leading to the improved electrical conductivity and Li-reversible capacity

Facile synthesis, microstructure and photophysical properties of core-shell nanostructured (SiCN)/BN nanocomposites

“…The C 1s spectrum has two peaks at 284.5 eV and 283.8 eV corresponding to graphite domains and Si−C bonds within SiC(N) in the nanocomposite. Furthermore, the Si 2p spectrum offers peaks at 100.4 eV and 102 eV attributed to Si−C bonds and Si−N bonds813, which are in good agreement with the FT-IR spectra. Attributed to Si−NH−Si groups, the peaks appearing at 3305 and 570 cm −1 are N−H stretching and Si−N, respectively8.…”

“…Both B 1s and N 1s spectra indicate the direction B–N bonding. A shoulder peak at higher energy (398.3 eV) indicated that the formation of the SiCN phase8. The C 1s spectrum has two peaks at 284.5 eV and 283.8 eV corresponding to graphite domains and Si−C bonds within SiC(N) in the nanocomposite.…”

“…In particular, SiC and BN semiconductor nanocrystals have enabled and transformed research in technologically important areas including biolabeling789, microelectromechanical (MEMS) and optoelectronic devices101112. For example, emission wavelengths can now be precisely controlled by the nanostructure composition, the average grain size and the formation of core-shell structures4131415.…”

“…The focus has been paid on the application of SiCN as a composite matrix material in the foregoing studies8. Thus, SiCN matrix composites have been made with filler phases of graphite21 or carbon nanofibers22, while many precursors-derived composites (e.g.…”

Electrochemical Li Storage Properties of Carbon-Rich B–C–N Ceramics

“…The composite materials consisting of graphite/carbon-poor SiCN or precursor-derived Si(B)CN coated-multiwalled carbon nanotube (CNT) composite exceed by far the sum of the capacities of the single components [27,29,30]. Further, promising efforts have been done by using SiCN as stabilizing matrix for MoS 2 [31] and boron nitride [32]. Core-shell silicon oxycarbide-carbon nanotubes composites demonstrate extremely high capacities of~800 mAh¨g´1 and good capacity recovering at high current [33], while embedding of silicon nanoparticles in SiOC matrix lead to material stabilization with respect to prolonged cycling [34,35].…”