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A high specific capacity conducting reduced graphene oxide nanosulfur nanocomposite (RGOSNC) cathode is synthesized via deposition of nanosulfur on graphene oxide (GO) through the hydrothermal treatment in the presence of multifaceted ethylenediamine (EDA) for improving the performance of lithium‐sulfur battery (LiSB). The maximum utilization of active material (sulfur) is facilitated by the attachment of nanosulfur to GO via EDA, and further, optimum reduction of GO into conducting, porous and interconnected RGO is performed via hydrothermal treatment in the available solution having residual EDA. Therefore, GO is reduced in highly conducting RGO without the use of any external reducing agent; minimizing the chance of impurity in the synthesized RGOSNC. A three‐dimensional interconnected porous conducting architecture with nitrogen (heteroatom) doping in RGO of RGOSNC with conductivity ∼1.83 S/cm assists easy electron transportation through conducting RGO network and stabilizes intermediate polysulfide to prevent loss of active material during the electrochemical performance. The synthesized RGOSNC cathode material delivers high initial specific capacities 1448 and 1040 mAh/g at 0.1 and 0.5 C, respectively. Prepared LiSB maintains ∼741 mAh/g retention over 100 cycles at 0.5 C with excellent Coulombic efficiency (∼99%).

Porous carbon nanospheres have received enormous attention due to their various applications. Although several elegant strategies exist for the synthesis of relatively large carbon nanospheres (>ca. 100 nm), the synthesis of carbon nanospheres with well-defined, tunable ultra-small sizes (

We report an efficient route for ferroelectric polar β phase generation in poly(vinylidene fluoride) (PVDF) through incorporation of amine functionalized, porous silica (MCM-41 and fumed silica) based nanofillers. These porous highly functionalized surfaces exhibit the efficient secondary interaction with polymer chain via hydrogen bonding. Structural analysis through FTIR, XRD, and TEM confirm high degree of ferroelectric polar β phase generation of PVDF through incorporation of amino modified porous silica nanofillers. Optimized loading (5 wt %) of amine functionalized, porous silica in PVDF matrix enhances relative intensity of β phase up to 75%. Disappearance of spherulite structure of PVDF with amino modified porous silica nanofillers, as confirmed through POM, TEM, SEM and AFM studies also supports the above conclusion. The P-E hysteresis loop at sweep voltage of ±50 V of a thin PVDF-amino modified porous nanofiller film shows excellent ferroelectric property with nearly saturated high remnant polarization 2.8 µC.cm−2 owing to its large proportion of β PVDF, whereas, a nonpolar pure PVDF thin film shows unsaturated hysteresis loop with 0.6 µC.cm−2 remnant polarization. PVDF films with the nanofillers exhibit strong adhesive strength over different metallic substrates making them have edge over PVDF in various thin film applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2401–2411

To meet the growing demand for rapid heat dissipation in electronic devices to ensure their reliable performance with a high level of safety, many polymer composites with thermally conductive but electrically insulating 2D boron nitride nanosheets (BNNSs) are being developed. Here we present an efficient way to enhance the thermal conductivity (TC) of a polymer composite by means of "grafting-from" polymerization of a poly(caprolactone) (PCL) onto BNNSs. The BNNSs, which were exfoliated from bulk BN by means of ultra-sonication, were prepared by means of radical oxidation. These oxidized BNNSs (oxi-BNNSs) were employed as initiators for subsequent ring-opening polymerization of PCL, which successfully resulted in PCL chemically grafted onto BNNSs (PCL-g-BNNSs). The excellent dispersion of PCL-g-BNNSs in common solvents allowed us to readily fabricate a polymer composite that contained PCL-g-BNNSs embedded in a PCL matrix, and the composite showed TC values that were five and nine times greater in the out-of-plane and in-plane mode, respectively, than those of pristine PCL.

Wrapping of reduced graphene oxide (RGO) over 2D layered transition metal oxide cathode material is very prevailing strategy to improve the capacity and cycling performance of cathode materials for sodium-batteries. However, poorly dispersed RGO in aqueous medium restricts the proper attachment of active-material with RGO resulting in non-uniform wrapping. Herein, graphene oxide is functionalized non-covalently through multifunctional agent dextran and reduced moderately to dextran functionalized-RGO (Dx-RGO). Further, it is attached chemically with Na[Ni0.60Mn0.35Co0.05]O2 (NMC) nano-sphere, which is synthesized by co-precipitation method. Strategically, hydrothermal-treatment is applied to empower reduction as well as attachment of Dx-RGO with NMC nano-sphere to prepare NMC-Dx-RGO composite. The successful attachment of Dx-RGO over NMC nano-sphere is confirmed by various experimental techniques and their resulting electrochemical performances are investigated. The surface-modified NMC-Dx-RGO cathode material exhibits high discharge capacity of 151 mAh g−1 at 0.1C and 55% capacity retention after 120 cycles at 0.2C. Dx-RGO layer acts as conducting network around NMC providing uniform state of charge distribution (SOC), which facilitates fast transport of electrons. The presence of protective Dx-RGO layer suppresses the growth of resistive layer at cathode-electrolyte interface (Rcei) and prevents the dissolution of transition metals cathode material to get high discharge capacity for sodium-batteries.

The composite cathode of sulfur-rich polymer and long cylindrical porous multiwalled carbon nanotubes (LCNT) is reported for high performance lithium-sulfur (Li–S) batteries through combining both chemical and physical binding strategies of sulfur, respectively. This technique efficiently exploits the synergistic effect of ability of stabilizing the polymeric sulfur. The role of uniform distribution of highly conductive LCNT network is optimized as a cathode host material by solution route. Annealed sulfur-co-polymer (S-co-poly) composites are homogeneously well attached via physisorption with LCNT submicron channel. The composite shows a high discharge capacity of 1040 mAh g−1 in the 1st cycle of galvanostatic charge-discharge at 0.5C. Whereas, the cell maintains a reversible capacity of 610 mAh g−1 after 200 cycles, showing good capacity rate. Therefore, solvent assisted both synthesis and further proper mixing enables high active material utilization whereas porous submicron channel of CNT network, which provides conducting pathway, adsorbs sulfur copolymer homogeneously for better electrochemical performance.