Qiang Zhao,Junhua Chen,Fubin Luo,Lu Shen,Ying Wang,Kun Wu,Mangeng Lu
Nanostructure of ordered polyaniline-graphene (PANI-rGO PMAS ) hybrid nanomaterials is assembled based on poly(2-methoxyaniline-5-sulfonic acid) (PMAS) functionalized reduced graphene oxide (rGO PMAS ) nanosheets. The presence of PMAS not only improves dispersibility of reduced graphene oxide nanosheets, but also plays a key role for heterogeneous nucleation of polyaniline (PANI) nanorods . The formation mechanism of ordered PANI-rGO PMAS hybrid nanomaterials was studied in details by using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and ultraviolet-visible spectrophotometry (UV–vis). The conductivity of PANI-rGO PMAS hybrid with 17 wt% rGO PMAS is as high as 4480 S/m, compared with 2.93 S/m for pure PANI. The cyclic voltammetry tests indicate that, PANI-rGO PMAS containing 2 wt% rGO PMAS possesses fast response to redox reactions and excellent reversible stability. It has a high specific capacitance of 385 F g −1 at the scan rate of 10 mV s −1 with potential ranges from −0.2 to 0.8 V. This ordered polyaniline-graphene hybrid has potential applications for flexible supercapacitors, sensors, batteries, electromagnetic materials and thermoelectric materials, etc.
Long Li,Chun Fang,Wenfei Wei,Lei Zhang,Zhao Ye,Gang He,Yunhui Huang
The huge volume change of silicon anode during cycling results in unstable solid electrolyte interface (SEI), causing rapid performance degradation . Natural SEI layer has a heterogeneous structure, results in the inhomogeneous Li + diffusion. The repeated destruction and regeneration of SEI aggravate the inhomogeneity of Li + diffusion at the interface, leading to non-uniform alloy reaction in the Si bulk. In this work, the silicon surface is passivated by an ultrathin uniform chitosan layer with abundant lithiophilic groups. The capacity of chitosan-coated Si (Si@CS) could reach 1500 mAh g −1 at a current density of 1 A g −1 , and the capacity retention remains 91% after 400 cycles. It is demonstrated that the oxygen and nitrogen atoms in chitosan are coordinated with Li + , providing uniformly distributed Li + transfer sites, results in a homogeneous Li + flux in the surface layer. Interestingly, a nano-scale ordered atomic arrangement is observed in the delithiated Si@CS, which contributes to more stable and reversible lithiation/delithiation reaction of the Si@CS electrode. It is proposed that optimizing the reaction interface on the Si surface is able to alter the Li-ion diffusion kinetics and structure transition behavior of silicon, which can improve the structure reversibility and stability during cycling.
危险品化学品经营许可证（带存储）