Zhiyu Wang,Jianli Cheng,Wei Ni,Lizhen Gao,Dan Yang,Joselito M. Razal,Bin Wang
A novel free-standing composite film electrode for Li-S battery is investigated. This novel electrode consists of polyvinylpyrrolidone-coated hollow sulfur microspheres (PVPS) that are homogeneously confined within the conductive composite matrix of graphene and poly(3,4-ethylene-dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS). The characteristic large surface area and wrinkled surface of graphene sheets allow the formation of a conductive layer on the surface of PVPS to suppress the polysulfide dissolution and accommodate the volumetric expansion of sulfur. The addition of PEDOT-PSS also enhances the adhesion between the PVPS and the graphene surface, the overall conductivity of the electrode, and the charge transportation during the charging and discharging processes. The best electrode performances are achieved for a composite film cathode with a sulfur content of about 63.9%, which delivers an initial specific capacity of around 1060 mAh g −1 at 0.1 C. This electrode also displays an excellent capacity retention of 75% after 500 cycles at 1C, corresponding to a capacity decay of only 0.05% per cycle.
Xiaodong Guo,Xin Wang,Xiongrui Liu,Yanyang Zheng,Jianzhong Xu,Haiyun Ma
A phosphazene derivative flame retardant with a highly cross-linked microsphere structure, named poly(cyclotriphosphazene-c-sulfonyldiphenol) (PCPS) microspheres, were synthesized by 1-pot reaction and then applied on flame retarded epoxy (EP) resin. The microstructure and chemical composition of PCPS microspheres were characterized using scanning electron microscopy, transmission electron microscopy, and element mapping. The thermal stability of PCPS microspheres and PCPS/EP composites was explored through thermogravimetric analysis. Thermogravimetric data showed that the PCPS microspheres have excellent thermal stability, and the char yield is about 43% at the end of 800°C. The incorporation of PCPS microspheres significantly increased the char yield of PCPS/EP composites. The flammability was investigated by limited oxygen index tests and cone calorimeter. The limited oxygen index value of PCPS/EP composite was increased to 29.8 from 26.6 when 3 wt% of PCPS microspheres was added. Compared with neat EP, the flame retardancy was greatly improved. The peak heat release rate and smoke production rate of PCPS/EP composites were reduced by 45.0% and 43.6%, respectively. The mechanical properties including tensile strength and modulus were both improved due to the enhancement of PCPS microspheres. The PCPS microspheres act as a dual function for improving both the flame resistance and mechanical strength of PCPS/EP system.
Fantao Meng,Malik Muhammad Umair,Kashif Iqbal,Xin Jin,Shufen Zhang,Bingtao Tang
Artificial construction of amorphous photonic structures (APSs) is an important approach for obtaining noniridescent structural colors and shows a great potential for practical applications in paints, textile coloring, display, or other color-related fields. However, the structural colors are usually dim because of the influence of incoherent scattering, and the point contact among the microspheres leads to poor structural stability. This paper presents an innovative strategy for constructing noniridescent structural color coatings with high color visibility, good structural stability, and self-healing properties by combining APSs with polymers. Color visibility is significantly improved without the addition of black light-absorbing substances because of the inherent properties of polysulfide microspheres. At the same time, the introduction of waterborne polyurea in the system enhanced the structural stability and imparted the self-healing properties. The prepared coatings can be applied to various substrates and even to the coloration of soft fabrics, which not only achieves excellent performance but can also be easily patterned on the bulk scale.
危险品化学品经营许可证（带存储）