Sandwich structured graphene-wrapped FeS-graphene nanoribbons （G@FeS-GNIKs） were developed. In this composite, FeS nanoparticles were sandwiched between graphene and graphene nanoribbons. When used as anodes in lith...Sandwich structured graphene-wrapped FeS-graphene nanoribbons （G@FeS-GNIKs） were developed. In this composite, FeS nanoparticles were sandwiched between graphene and graphene nanoribbons. When used as anodes in lithium ion batteries （L1Bs）, the G@FeS-GNR composite demonstrated an outstanding electrochemical performance. This composite showed high reversible capacity, good rate performance, and enhanced cycling stability owing to the synergy between the electrically conductive graphene, graphene nanoribbons, and FeS. The design concept developed here opens up a new avenue for constructing anodes with improved electrochemical stability for LIBs.展开更多
The electrical properties of chemically derived graphene and graphene grown by chemical vapor deposition （CVD）, until now, have been inferior to those of mechanically exfoliated graphene. However, because graphene i...The electrical properties of chemically derived graphene and graphene grown by chemical vapor deposition （CVD）, until now, have been inferior to those of mechanically exfoliated graphene. However, because graphene is easier to produce in large quantities through CVD or growth from solid carbon sources, it has a higher potential for use in future electronics applications. Generally, modifications to the pristine lattice structure of graphene tend to adversely affect the electrical properties by shifting the doping level and changing the conductivity and the mobility. Here we show that a small degree of graphene surface functionalization, using diazonium salts with electron-withdrawing and electron-donating functional groups, is sufficient to predominantly induce p-type doping, undiminished mobility, and higher conductivity at the neutrality point. Molecules without a diazonium anchor group desorb easily and do not have a significant effect on the electronic properties of graphene devices. We further demonstrate the variability between identically fabricated pristine devices, thereby underscoring the caution needed when characterizing graphene device behaviors lest conclusions be drawn based on singular extremes.展开更多
文摘Sandwich structured graphene-wrapped FeS-graphene nanoribbons （G@FeS-GNIKs） were developed. In this composite, FeS nanoparticles were sandwiched between graphene and graphene nanoribbons. When used as anodes in lithium ion batteries （L1Bs）, the G@FeS-GNR composite demonstrated an outstanding electrochemical performance. This composite showed high reversible capacity, good rate performance, and enhanced cycling stability owing to the synergy between the electrically conductive graphene, graphene nanoribbons, and FeS. The design concept developed here opens up a new avenue for constructing anodes with improved electrochemical stability for LIBs.
文摘The electrical properties of chemically derived graphene and graphene grown by chemical vapor deposition （CVD）, until now, have been inferior to those of mechanically exfoliated graphene. However, because graphene is easier to produce in large quantities through CVD or growth from solid carbon sources, it has a higher potential for use in future electronics applications. Generally, modifications to the pristine lattice structure of graphene tend to adversely affect the electrical properties by shifting the doping level and changing the conductivity and the mobility. Here we show that a small degree of graphene surface functionalization, using diazonium salts with electron-withdrawing and electron-donating functional groups, is sufficient to predominantly induce p-type doping, undiminished mobility, and higher conductivity at the neutrality point. Molecules without a diazonium anchor group desorb easily and do not have a significant effect on the electronic properties of graphene devices. We further demonstrate the variability between identically fabricated pristine devices, thereby underscoring the caution needed when characterizing graphene device behaviors lest conclusions be drawn based on singular extremes.
