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To data, combination of Pt-based bimetallic nanocrysatals and the graphene support have significantly contributed to enhance the oxygen reduction reaction (ORR) performance relative to electrocatalysts based on monometallic Pt nanoparticles (NPs) primarily due to the unique ligand effects and benefits of the carbon support. In this study, we propose a new structure of bimetallic electrocatalysts to realize the synergistic effects on the ORR performance through effective integration of the fine-sized Pt NPs, PdPt bimetallic nanocrystals, and non-covalently functionalized graphene with ionic polymers. The facile wet-chemical methods were applied to synthesize fine-sized (2–5 nm) spherical Pt NPs doped large-sized (20–50 nm) non-spherical PdPt bimetallic NPs on the electronically negative ionic polymer-functionalized graphene support (Pt-on-PdPt/fG). This Pt-on-PdPt/fG with synergistic effects based on enlarged active surface area, ligand, and interfacial linking effects, exhibits substantially enhanced ORR activity (specific activity: 1.89 mA c m Pt − 2 at 0.9 VRHE) and durability in comparison to the commercial Pt/C (specific activity: 0.23 mA c m Pt − 2 at 0.9 VRHE). To this end, the effective integration of newly designed fine-sized Pt NPs doped bimetallic nanocrystals and unique graphene supports with the well-interactive ability could be a good platform to develop the advanced electrocatalysts for the efficient ORR.

A series of ionic liquids containing imidazolium, pyrrolidinium, or ether-functionalized pyrrolidinium cations incorporated with the same counter anion of bis(fluorosulfonyl)imide (FSI − ) were synthesized to investigate the effects of the cation structures on the physical and electrochemical properties of ionic liquids. The introduction of the polar ether group was able to compensate for the loss of the mobility of pyrrolidinium cation-based ionic liquids, while maintaining the high thermal and electrochemical stability. Extensive examinations of these ionic liquids in electric double-layer capacitor (EDLC) cells were performed to investigate their voltage stability under various operating conditions. Electrochemical evaluation revealed that the cell fabricated with ether-functionalized pyrrolidinium ionic liquid could deliver larger capacitance values and stable cycling performance compared with the cell containing imidazolium-based ionic liquid at high operating voltage; demonstrating its possible applications as high voltage electrolytes for EDLCs.

Boron containing ionogels were fabricated through chemical crosslinking of boron allyloxide with polyethylene glycol dimethacrylate in an ionic liquid electrolyte solution to obtain mechanically robust gels. Because of the relatively small concentration of crosslinking agent required to fully solidify the ionic liquid electrolyte, good characters of high ionic conductivity, high thermal stability, and good electrochemical stability were observed. A spectroscopic investigation of the boronic ionogels revealed that the lithium mobility was noticeably enhanced compared with ionogels fabricated without the boronic crosslinker, leading to promising Li-ion battery performance at elevated temperatures.

We present a new polyethylene glycol-functionalized polysilsesquioxane, a ladder-like structured poly(poly(ethylene oxide)-co-methacryloxypropyl)silsesquioxane) (PEO-SQ) hybrid-type polymer gelator to fabricate hybrid ionogel electrolytes for lithium ion capacitors. The organic-inorganic hybrid polymer gelator contains not only an inorganic ladder-like polysilsesquioxane backbone for the thermal and electrochemical stability, but also dual organic pendant groups consisting of free-dangling PEO chains and unsaturated methacryloxypropyl groups for enhanced lithium ion dissociation and thermal curing function, respectively. The successful crosslinking of 1 M LiTFSI in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) ionic liquid with only a small amount of PEO-SQ hybrid crosslinker (5 wt%) gave non-leaking ionogels with high thermal stability (⿼400 °C), large ionic conductivities, and excellent lithium ion capacitor C-rate performance and cyclability, comparable to those of neat ionic liquid electrolyte and superior over conventional organic ionogels fabricated with organic crosslinkers without PEO-moeities.