A tin nanoparticle/polypyrrole (nano-Sn/PPy) composite was prepared by chemically reducing and coating Sn nanoparticles onto the PPy surface. The composite shows a much higher surface area than the pure nano-Sn reference sample, due to the porous higher surface area of PPy and the much smaller size of Sn in the nano-Sn/PPy composite than in the pure tin nanoparticle sample. Poly(vinylidene fluoride) (PVDF) and sodium carboxymethyl cellulose (CMC) were also used as binders, and the electrochemical performance was investigated. The electrochemical results show that both the capacity retention and the rate capability are in the same order of nano-Sn/PPy-CMC > nano-Sn/PPy-PVDF > nano-Sn-CMC > nano-Sn-PVDF. Scanning electronic microscopy (SEM) and electrochemical impedance spectroscopy (EIS) results show that CMC can prevent the formation of cracks in electrodes caused by the big volume changes during the charge-discharge process, and the PPy in the composite can provide a conducting matrix and alleviate the agglomeration of Sn nanoparticles. The present results indicate that the nano-Sn/PPy composite could be suitable for the next generation of anode materials with relatively good capacity retention and rate capability.
", PPy can be used as both a conductive matrix and host of lithium ion accommodation. With a negligible capacity below 2.0 V, only the high elasticity and the conductivity of PPy are applied to form composites with improved rate and/or cycling stability of graphite , Sn , Si , and SnO 2  . Moreover, Wu et al. reported that PPy coating could prevent the dissolution of the electrode materials, such as V 2 O 5 , LiV 3 O 8  and MoO 3  in aqueous rechargeable lithium battery, and provide not only good cycling performance but also excellent rate capability. "
[Show abstract][Hide abstract] ABSTRACT: Organic electrode materials have long been proposed but their electrochemical performances are far from satisfactory in, for example, specific capacity and cycling stability, for secondary batteries. This article reports the electrochemical performance of a composite of polypyrrole (PPy) and nickel oxide (NiO), in which another lithium storage material, polypyrrole–nickel–oxygen (PPy–Ni–O) coordination complex, was fabricated during initial galvanostatically discharging. Extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate the process of the electrochemical formation of a PPy–Ni–O coordination and determine its multilayer structure. The strong and electrochemically stable coordination between the nickel and nitrogen atoms ensures the excellent electrochemical performances of the complex. These findings pave new ways to construct a new type of high-performance organic anode material for lithium ion batteries.
[Show abstract][Hide abstract] ABSTRACT: SnO2-polypyrrole hybrid nanowires are synthesized in a one-step process by a simple electrochemical method from an aqueous solution at room temperature. This novel and facile technique involves the rapid electropolymerization of pyrrole and the relatively slow chemical deposition of SnO2, which leads to the incorporation of uniformly dispersed SnO2 nanoparticles inside polypyrrole nanowires. Notably, the synthesized nanowires are directly deposited as a thin film on the substrate in a three-dimensional porous and interconnected network structure composed of numerous fine nanowires. This open architecture is highly desirable in energy storage devices because of its excellent mass transfer and high specific surface area, and therefore, the SnO2-polypyrrole hybrid nanowires are evaluated for their use as high-performance anode materials in Li-ion batteries. Over 200 cycles, the hybrid nanowires show superior cyclic performance and a charge capacity higher than 0.307 mA h cm−2, most likely because the polypyrrole matrix effectively prevents the agglomeration of the SnO2 nanoparticles and elastically buffers the volumetric change in the nanoparticles that occurs during cycling.
[Show abstract][Hide abstract] ABSTRACT: Polypyrrole nanowires are successfully fabricated with a one-step process by cathodic electropolymerization from an aqueous solution without templates and chemical additives. The method utilizes electrochemically generated NO+ to oxidize the neutral pyrrole monomers, making it possible to use oxidizable metal substrates, such as Cu and Ni. The synthesized nanowires are directly deposited on the substrate in the form of a thin film consisting of fine polypyrrole nanowires with a nanoporous and interconnected network structure. The growth kinetics of the polypyrrole nanowires was investigated by analyzing the effects of the chemical composition of the electrolyte and the synthesis time on the formation of polypyrrole nanowires. It was found that the polymerization process of pyrrole is very sensitive to the reactivity of radical cations. For a radical cation with high reactivity, the polypyrrole nanospheres are synthesized near the electrode in the solution. In contrast, for a radical cation with sufficiently low reactivity, the polypyrrole nanowires are grown on the priorly deposited polypyrrole nanospheres.
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