A bis-imino-acenaphthenequinone (BIAN)–fluorene copolymer (π conjugated polymer bearing BIAN and fluorene units) binder was designed, synthesised and used for the fabrication of a graphite electrode in lithium-ion batteries. Unlike the PVDF binder, the electrode with the BIAN–fluorene binder exhibited significantly improved electrochemical performance in terms of its rate capability, cycling behaviour and specific capacity. At a rate of 1C, the electrode with the BIAN–fluorene binder exhibited more than 250 mA h g−1 capacity after 100 cycles while the electrode made with the PVDF binder delivered only 165 mA h g−1. The significant improvement of cycling performance is due to the improvement in the adherence of the electrode laminate to the current collector and improved interface. Electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy studies showed the formation of an improved interface with the BIAN–fluorene based binder.

•Several imidazolium TFSI/FSI derivatives were found to be miscible with boric ester.•One of the binary electrolytes showed extraordinary high lithium transference number of over 0.9.•After fabricating anodic half-cell (Li/electrolyte/Si), specific discharge capacity exceeding 2500 mAhg− 1 was observed.Binary electrolytes composed of ionic liquids and boric esters were prepared by studying compatibility between various combinations of such systems. The study showed that out of various combinations of ionic liquids/boric esters, only TFSI anion (or FSI anion) based ionic liquids/mesityldimethoxyborane (MDMB) systems were found to be miscible. After equimolar amount of lithium salts was added to ionic liquids, the resulting solution showed high ionic conductivity that was comparable to those for ionic liquids. The lithium transference number (tLi +) of these systems at room temperature was found to be very high. A maximum tLi + of 0.93 was observed for a binary mixture of AMImFSI [1-allyl-3-methylimidazolium bis(fluorosulfonyl)imide]/MDMB. Further, this binary mixture as electrolyte in Li/electrolyte/Si cell showed good reversible lithiation-delithiation with > 2500 mAh/g of delithiation specific capacity.Download high-res image (86KB)Download full-size image

There are a number of π-conjugated organoboron polymers in which π-conjugation is extended via the vacant p-orbital of the boron atom. However, boron incorporation into σ-conjugated systems has not been reported so far. A novel σ-p conjugated copolymer of phenylsilane and mesitylborane was synthesized by dehydrocoupling polymerization using a rhodium catalyst. Change in electronic states due to the incorporation of the boron moiety was determined both by DFT calculations and experiments. The obtained colorless polymers were characterized by 1H-NMR and 11B-NMR spectra. Incorporation of boron was confirmed by 11B-NMR, while the Si/B ratio was calculated by 1H-NMR integration ratios. GPC analysis showed the Mn of the polymer as 1200–2900 g mol−1. The copolymers showed high sensitivity towards fluoride ions both optically and electrochemically exhibiting a “turn on” type of sensing mechanism.

Facile synthesis of alternating copolymer poly(borosiloxane) via dehydrocoupling was successfully carried out in the presence of transition metal catalyst at room temperature. The polymer was characterized by NMR and IR spectroscopy. The presence of a single peak in 11B NMR and 29Si NMR supported the alternating sequence of the polymer which was further complimented by the study of specifically designed model reactions. Fluoride ion sensitivity was analyzed by electrochemical methods.. The anion selective electrode prepared using synthesized polymer was found to be extremely sensitive toward fluoride ions (10–10 M in aqueous media) by potentiometric measurements using 0.1 M disodium hydrogen phosphate as supporting electrolyte, Ag/AgCl as reference electrode, and Pt wire as counter electrode.Keywords: dehydrocoupling polymerization; fluoride ion sensing; ion-selective electrode; polyborosiloxane; potentiometry

We report the synthesis of a crystalline cyclic organoboron compound that shows an anomalous Li-ion conduction behaviour with specific composition and method of insertion of a Li salt. The enhanced ionic conductivity of crystalline boric ester/LiTFSI prepared by the grinding method should be due to the formation of regulated ion-conduction channels scaffolded by boron–anion interaction.

A novel single-pot method to exfoliate and functionalize acetylene black is proposed. The deliberate functionalization was found to enhance the intrinsic oxygen reduction efficiency along with the nucleation and growth of platinum nano-particles on the surface. The resulting material showed enormously high oxygen reduction reactivity compared to its commercial counterparts.

Poly(N-isopropylacrylamide), PNIPAM, is a thermoresponsive polymer widely known for its lower critical solution temperature (LCST) phenomenon at 32 °C in aqueous solutions. Precise tuning of the LCST of PNIPAM to a broader temperature range offers a larger window of applications especially in the field of biotechnology and nanotechnology. A series of free radical random copolymerizations between N-isopropylacrylamide (NIPAM) and various imidazolium based ionic liquids (ILs) were conducted. IL structures were varied in terms of their alkyl chain length at the N-3 (or N-1) position of the imidazolium ring and counter anion. The LCST behavior of the aqueous solutions of the copolymers was investigated through UV-VIS transmission measurements. The results confirm that introduction of IL into the PNIPAM offers a wide range of LCST behaviors with a synergism between the hydrophobic part of the ionic liquid and the basic strength of the counter anion, probably by varying the hydrogen bonding abilities of the copolymer.

•Ion-gels composed of borosilicate and low viscous ionic liquids were prepared.•The ion-gels obtained showed maximum ionic conductivity of 2.0 mS cm−1 at 324 K.•Hybrid ion-gels including LiPF6 showed higher ionic conductivity.•Hybrid ion-gels including LiTFSA was highly homogenous and thermally stable.Research towards the design of novel electrolytes for the development of safer and efficient Li-ion batteries has gained widespread momentum in recent years. Design of novel borosilicate glass/ionic liquid hybrid type electrolyte was undertaken. Organic–inorganic hybrids have the dual advantages of high ionic conductivity due to the organic component and high thermal stability due to the inorganic components. In the present work, an in-situ sol–gel method using alkoxysilanes and alkoxyboranes was carried out, in the presence of low viscous ionic liquids. This resulted in the formation of highly homogenous organic–inorganic hybrids. A low viscous diallylimidazolium type ionic liquid was employed as the organic component. Arrhenius plots evinced constant temperature dependence of ionic conductivity. A maximum ionic conductivity of 2.0 mS cm−1 at 51 °C, was observed among the prepared hybrids. LiPF6 based hybrids showed higher ionic conductivity due to larger phase separation order of organic and inorganic components which enables better connection of ion-conductive organic components. On the other hand, LiTFSA based hybrids were highly homogenous and exhibited much improved thermal stability.

Solid polymer electrolytes are still collecting attention today for development of safer Li-ion batteries. Introduction of boron moieties to electrolytes generally improves ion conductive properties of resultant electrolytes. Herein, we have undertaken dehydrocoupling reaction between glycerol (Gly)/triethylene glycol (TEG) and hydroborane to synthesize highly branched organoboron polymer electrolytes. Increase in amorphous nature of polymer due to branched structure improved the ionic conduction. This was supported from decreased Vogel–Fulcher–Tammann parameters corresponding to activation energy of ion transport in matrices. When Gly content was increased beyond [Gly]/[TEG] = 15%, ionic conductivity decreased due to decrease in solubility of the salt in organoboron polymer matrix.

Novel organoboron ion-gel electrolytes bearing boric ester were prepared under a mild reaction condition by dehydrocoupling of cellulose with hydroborane in ionic liquid. The organoboron ion-gels obtained showed ionic conductivity of 6.3 × 10− 4–1.1 × 10− 4 S cm− 1 at 324 K. The desired ion-gels were successfully prepared during the reactions for 1 h. The ion-gels prepared using mesitylborane showed higher ionic conductivity in comparison with ion-gels prepared from BH3–THF complex. Different from ordinary polymer ion-gels, the addition of lithium salt led to further increased ionic conductivity. This should be due to the high dissociation degree of LiCl in the presence of boron, as indicated from increased VFT (Vogel–Fulcher–Tammann) parameter corresponding to carrier ion number in the matrices.Highlights► Ion-gels including boric ester were conveniently prepared using cellulose. ► The ion-gels obtained showed ionic conductivity exceeding 10– 4 Scm– 1 at 324K. ► Addition of Li salt led to higher ionic conductivity. ► Ion-gels derived from mesitylborane showed higher ionic conductivity.

We report the synthesis of a crystalline cyclic organoboron compound that shows an anomalous Li-ion conduction behaviour with specific composition and method of insertion of a Li salt. The enhanced ionic conductivity of crystalline boric ester/LiTFSI prepared by the grinding method should be due to the formation of regulated ion-conduction channels scaffolded by boron–anion interaction.

A novel single-pot method to exfoliate and functionalize acetylene black is proposed. The deliberate functionalization was found to enhance the intrinsic oxygen reduction efficiency along with the nucleation and growth of platinum nano-particles on the surface. The resulting material showed enormously high oxygen reduction reactivity compared to its commercial counterparts.