This paper introduced a general method of etching suspended graphene by nonmetallic SiO x nanoparticles (SiO x NPs) in graphene synthesis. Effects of etching time, concentration of silica gel and type of graphene on the etching mode of graphene have been systematically considered with using as-grown graphene film on a silica gel coating copper as model system. Nonmetallic SiO x NPs acted as etchant plays important role in the in situ etching process during the fabrication of graphene. The etched multilayer graphene pattern can be modulated from large area films to a rectangle pattern by varying the Si concentration and etching time, while single layer graphene pattern alters little. The morphology and critical structure of SiO x etched graphene were characterized by Raman spectra, transmission electron microscopy, scanning electron microscope and X-ray photoelectron spectrum. The process and mechanism described here open the way for tailoring graphene via nanoparticles instead of metal, which show significant influence of the electrical properties of graphene.
Guangfa Shi,Xiaomin Cai,Wenqiang Wang,Gengchao Wang
Polymeric positive temperature coefficient (PTC) materials can be used to install “brake” technology for the thermal runaway of lithium-ion batteries. However, it still has poor cycle stability and obvious negative temperature coefficient (NTC) effect, which reduces the reliability of the material. In order to solve these problems, conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) modified multilayer graphene (MLG) conductive additive (PEDOT-MLG) is introduced into middle density polyethylene/carbon black (MDPE/CB) system. Compared with the conventional modification, the PEDOT modified MLG shows high conductivity and excellent thermal stability. In addition, the introduction of PEDOT-MLG into MDPE/CB can further reduce the room temperature resistivity due to the good compatibility between the modified graphene and the matrix, thus improving the PTC intensity to 7.1. What is more, MLG limits the re-aggregation of CB particles when the temperature further rises, which effectively weakens the NTC effect.
危险品化学品经营许可证（带存储）