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The poor electronic conductivity and low lithium ion diffusion rate of a LiFePO 4 cathode material are the two major obstacles for its commercial applications in the power lithium ion batteries. This article utilized an electroactive and ion conductive copolymer, polyaniline-poly(ethylene glycol) (PANI-PEG), to modify carbon-LiFePO 4 (cLFP) by a facile in situ chemical copolymerization method. The structure and morphology of the cLFP/PANI-PEG composite were confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with a cLFP/PANI composite, the cLFP/PANI-PEG composite exhibited a more uniform and full polymer coating layer. Furthermore, this cLFP/PANI-PEG cathode material exhibits excellent cyclic stability (95.7% capacity retention after 100 cycles at 0.1 C) and high rate capability (125.3 mA h g À1 at 5 C) as the PANI-PEG copolymer coating layer facilitated electron and ion transport within the electrode. Electrochemical impedance spectroscopy (EIS) proved that the lithium ion diffusion in the cLFP/PANI-PEG composite was increased significantly by one order of magnitude compared with cLFP, indicating its possibility to be served as a cathode material for high-performance lithium ion batteries.

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The alcohols, methanol, ethanol, ethylene glycol (EG), and glycerol, were used as reducing agents for iron(III)-catalyzed activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate in polar solvents (N,N-dimethylformamide, N-methylpyrrolidone, or acetonitrile). The effects of the iron catalyst, initiator and alcohol on polymerization were investigated, and most of the systems showed the typical features of controlled radical polymerization. In studies of the ATRP behavior, polymerizations were well controlled with a linear increase in the molecular weight (Mn) versus conversion in agreement with the theoretical one, and low molecular weight distributions (Mw/Mn) were observed throughout the reactions. To gain a deeper understanding of the iron(III)/polar solvent-mediated ATRP, the polymerizations of various monomers (methyl acrylate, methyl methacrylate, n-butyl acrylate, and n-butyl methacrylate) were also investigated.

Recently, stringent requirements brought on by environmental regulations and safety issues are driving the development of solid electrolytes to replace conventional liquid electrolyte systems for lithium‐based secondary batteries (LiBs). However, the low Li‐ion conductivity and/or poor mechanical properties of electrolytes remain the main obstacles hindering their commercialization. Hierarchitectural and composite polymer separators (CPSs) based on electrolyte membranes have been reported as promising tools for both high ionic conductivity and mechanical stability. In light of such work, the new types of flexible electrolytes based on phase‐separated and mixed‐phase morphologies achieved via self‐assembly and the use of functional molecular composites are reviewed along with the fundamental mechanisms associated with such systems. In particular, the structure and morphology, ionic conductivity, thermal/mechanical stability, and fabrication of polymer electrolytes are introduced. Additionally, recent advancements in CPSs including methods of ensuring low interfacial resistance, the respective contributions of these critical factors to the significant functional properties of CPSs, and directions for development and essential applications in the field of CPSs for LiBs are presented. Based on previous works, the perspectives put forth will aid in the design of advanced electrolytes for practical Li secondary batteries in the near future.

Novel SPPSU-based IPMC membranes with different ion exchange capacities were synthesized. SPPSU4-based IPMCs showed the best actuation performance.