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In this paper, a series of iron oxide/reduced graphene oxide/carbon nanotube composites (K3‐Fe2O3‐rGO/CNT) with well‐dispersedFe2O3 particles are prepared by in situ reaction and then heat‐treatment, and its electrochemical and battery performancesare studied as the anode material of lithium‐ion batteries. The results show that the introduction of reduced graphene oxide/carbon nanotube (rGO/CNT) improves the electrochemical and battery performances of the prepared electrode material. In particular, the K3‐Fe2O3‐rGO/CNT (30 %) composite material has a reversible capacity of 1559 mAh g−1 after 100 charge/discharge cycles at 100 mA g−1. And its specific discharge capacityis 641.1, 639.7, 609.5, 578.6 and 543 mAh g−1at the current density of 100, 200, 500, 1000 and 2000 mA g−1, respectively,with 84.7 % of capacity retention even with a 10 times increase in current density. The research of charge storage indicates that the electrochemical process is a mixed control process of diffusion and capacitance. The improved electrochemical and battery performancesfor the composite electrode material can be attributed to the enhanced dispersion of the Fe2O3 and the enhanced conductive network provided by rGO/CNT composite carbon. It makes a promising way to prepare high performance of anode material for lithium‐ion battery. [ABSTRACT FROM AUTHOR]

Silicon-carbon materials have a promising development as anode materials for lithium-ion batteries. In this experiment, sucrose carbon/silicon composites (SC/Si) were prepared by hydrothermal and high-temperature carbonization methods, and on this basis, sucrose carbon/silicon graphite composites (SC/Si-Gr) with graphite conductive skeleton structure were prepared and investigated for their electrochemical and battery performance as anode materials for lithium-ion batteries. The results reveal that sucrose carbon is evenly coated on the surface of silicon nanoparticles, and that the electrochemical and battery performance of the produced sucrose carbon/silicon composites improve with increasing sucrose carbon concentration. With the introduction of graphite, the electrochemical performance of the constructed SC/Si-Gr ternary composites is further enhanced. When the sucrose: silicon: graphite feeding mass ratio is 1:1:0.5, the formed SC/Si-Gr (1:1:0.5) composite has a discharge specific capacity of 1 005.1 mAh/g after the third cycle of stability at a current density of 0.1 A/g. The discharge specific capacity is 819 mAh/g after 100 cycles, and the charge/discharge Coulomb efficiency is maintained at about 98%. The average discharge specific capacity is 437.91 mAh/g at a high current density of 1 A/g. This is due to the addition of graphite, which creates a strong conductive skeleton structure and boosts lithium ion transport rate and first cycle Coulomb efficiency. As a result, the sucrose carbon/silicon-graphite composite exhibits good cycle stability and charge/discharge the rate performance. [ABSTRACT FROM AUTHOR]

Developing advanced organic cathodes with significant charge–discharge performances would prove a potential alternative for traditionally inorganic cathode materials of lithium-ion batteries in the future. Herein, a conductive polymer as electrode with improved electrochemical performances was reported. Polyaniline (PANI) with fibrous morphology was firstly polymerized by using perchloric acid (HClO4) as the large molecular doped acid. Furthermore, the cross-linking PANI was prepared with using triphenylamine as the cross-linkers and p-phenylenediamine as the molecular chain extender. Applied as the cathode of lithium-ion batteries, the cross-linking PANI fibers with moderate cross-linking degree exhibited an improved electrochemical and cell performances, in which it presented a highest discharge specific capacity of 138.5 mAh·g−1 and a relatively stable capacity retention of around 126.3 mAh·g−1 after 150 cycles. Also, the cross-linking PANI exhibited the improved rate capabilities, and it could still provide a discharge specific capacity of 92.5 mAh·g−1 even at a higher current density of 500 mA.g−1, which is obviously higher than that of pure PANI. The work presented herein demonstrated that the cross-linking for conductive polymers was a potential way to obtain the improved electrochemical performances for the polymer-based electrode material. [ABSTRACT FROM AUTHOR]

The study of phonon scattering processes is urgent for advancing the thermoelectric material with low thermal conductivity for commercial application. In this work, Raman scattering spectroscopy is utilized to quantify the temperature dependence of vibrational modes in ZrTe5 crystals, which enables the investigation on anharmonic contributions. We mainly focus on the temperature range from 80 up to 400 K due to noticeable surface oxidation at higher temperature. The phonon behaviors can be fully described by the model considering two mechanisms of the lattice thermal expansion effects and intrinsic anharmonicity. The four‐phonon processes are non‐negligible and even stronger than the three‐phonon processes at high temperature. The phonon lifetime is greatly reduced by the enhancement of phonon scattering, contributing to the low thermal conductivity in ZrTe5 single crystals. [ABSTRACT FROM AUTHOR]

Silicon-carbon materials have broad development prospects as negative electrode materials for lithium-ion batteries. In this paper, polyvinyl butyral (PVB)-based carbon-coated silicon (Si/C) composite materials were prepared using PVB-coated Si particles and then high-temperature carbonization methods. Furthermore, the PVB-based carbon-coated silicon/artificial graphite composite materials (Si/C-Gr) were prepared by using artificial graphite as conductive skeleton. And the electrochemical and battery performances of Si/C and Si/C-Gr composite materials as negative electrode materials of lithium-ion batteries were investigated in detail. The results showed that PVB-based carbon was uniformly coated on the surface of silicon particles, and the electrochemical performance and battery performance of the Si/C composite material was improved with the increasing proportion of PVB in the reaction feed. With the introduction of artificial graphite, the constructed ternary composite of Si/C-Gr as anode exhibited a further improved electrochemical performances, such as cycling stability, rate performance, and coulombic efficiency. Specially, the Si/C-Gr (1:30:0.7) composite anode has a discharge specific capacity of 1239.9 mAh/g in the first cycle and 922.9 mAh/g in the 100th cycles at a current density of 0.1 A/g. And the corresponding coulombic efficiency was 84.5% in the first cycle and maintained at around 98% after 100 cycles. The average discharge specific capacity was 1045.5, 796.08, 688.75, 507.09, and 479.11 mAh/g at the current rate of 0.1, 0.2, 0.4, 0.8, and 1 A/g, respectively. This is attributed to the addition of artificial graphite forming an effective conductive skeleton structure, which enhanced the structural stability of the composite material and improved the electronic conductivity of the electrode material. Also, PVB as functional coating polymer improved the dispersion of Si particles on the surface of graphite. All above reasons enabled the electrode materials to have good electrochemical performances. [ABSTRACT FROM AUTHOR]

The exploration of organic materials for electrochemical energy storage has attracted much attention, and our studies focus on quinone‐based polymer that is employed as the electrode materials for lithium‐ion batteries. In this article, two poly(arylamino‐quinone) polymers are prepared by Michael addition polymerization reaction. The constructed poly(arylamino‐quinone) polymers contained the quinone units in arylamine‐linked conjugated skeleton, which possess the branched molecular structure for poly (tris(4‐aminophenyl)amine‐benzoquinone) (PAQ1) and the linear molecular structure for poly (p‐phenylenediamine‐benzoquinone) (PAQ2), respectively. As explored as the organic cathode materials for lithium‐ion batteries, PAQ1 with granular morphology exhibits the discharge capacity of 429.6 mAh. g−1 in the first cycle and the improved average discharge potential. Also, it shows that the stable cycling stability after the capacity attenuation in the initial cycles and the high current rate performances as comparing to PAQ2. It can be ascribed to the introduction of triphenylamine unit in polymer and the assembled granular morphology, which contributes to improved electrochemical performances for PAQ1. [ABSTRACT FROM AUTHOR]

The understanding of phonon–phonon anharmonic effect in HfTe5 is essential not only for fundamental scientific interest but also for its potential thermoelectric applications. Here, rectangular ribbon‐shaped HfTe5 single crystals have been grown. Raman spectroscopy is further utilized to investigate the phonon anharmonicity of HfTe5 by quantifying the temperature dependence of the phonon mode softening and broadening. We focus on the temperature range from 80 up to 400 K since obvious surface oxidation occurs at higher temperatures. It is found that four phonon anharmonic effects are non‐negligible. The phonon lifetime is greatly reduced by the enhancement of phonon scattering, resulting in the low thermal conductivity in HfTe5 single crystals. [ABSTRACT FROM AUTHOR]

In this paper, polyaniline/FeFe(CN)6(PANI-FeFe(CN)6) composites were prepared by a simple in-situ oxidation polymerization in perchloric acid (HClO4) solution in which the obtained polyaniline (PANI) self-assembled to form the tube-like morphology, while FeFe(CN)6 with perfect face-centered cubic lattice (FCC)-type structure was well-dispersed in the obtained PANI matrix. As the cathode of lithium ion battery, PANI-FeFe(CN)6 composite demonstrates the improved specific capacity, cycling stability and current rate performances. For PANI-FeFe(CN)6 composite prepared by feed mass ratio of FeFe(CN) 6 : Aniline to 80:100 (PANI-FeFe(CN)6(80%)), it still remained 95.7 mAh/g of discharge capacity after 100 cycles, indicating its excellent cycling performances. Especially, its specific capacities were 95.9, 98.8, 91.4, 83.6 and 72 mAh/g at the current density of 20, 50, 100, 200 and 500 mA/g, which were obviously higher than that of PANI or FeFe(CN)6, respectively. The improved thermal stability and electrochemical performances for PANI-FeFe(CN)6 composites could be ascribed to the formed interaction between PANI and FeFe(CN)6 components and the enhanced electrical conductivity, which made it a potential candidate as the cathode of lithium battery. PANI-FeFe(CN)6 composites were prepared by a simple in-situ oxidation polymerization in HClO4 solution, in which the obtained polyaniline (PANI) self-assembled to form the tube-like morphology, while FeFe(CN)6 with perfect face-centered cubic lattice (FCC)-type structure was well-dispersed in the obtained PANI matrix. As the cathode of lithium ion battery, PANI-FeFe(CN)6 composite demonstrates the improved specific capacity, cycling stability and current rate performances. For PANI-FeFe(CN)6(80%), it still remained at 95.7 mAh/g of discharge capacity after 100 cycles, indicating its excellent cycling performances. Especially, its specific capacities were 95.9, 98.8, 91.4, 83.6 and 72 mAh/g at the current densities of 20, 50, 100, 200 and 500 mA/g. The improved thermal stability and electrochemical performances for PANI-FeFe(CN)6 composites could be ascribed to the formed interaction between PANI and FeFe(CN)6 components and the enhanced electrical conductivity, which made it a potential candidate as the cathode for lithium battery. [ABSTRACT FROM AUTHOR]

Prussian-blue type FeFe(CN)6 nanocrystals with perfect nanocubic morphology were prepared by a facile hydrolytic precipitation method using Fe(CN) 6 3 − as a single iron-source. The resulting FeFe(CN)6 nanocrystals have subsequently been encapsulated within a mixed electronically and ionically conducting polystyrene sulfonic acid (PSS)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) (PEDOT-PSS) with ethylene glycol (EG) as the polar solvent to obtain a high electrical conducting organic–inorganic nanohybrid. The FeFe(CN)6/PEDOT-PSS nanohybrid offers discharge capacity of 1 0 6. 3 mAh ⋅ g − 1 , which is improved compared to that of the naked FeFe(CN) 6 (9 4. 4 mAh ⋅ g − 1). Also, it demonstrated the improved capacity retention and rate capability, which makes it a promising way for high performance Li-ion batteries for energy storage application. Electrically conductive Prussian-blue type FeFe(CN)6 nanocrystals were prepared by coating a polystyrene sulfonic acid (PSS)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) (PEDOT-PSS) in ethylene glycol (EG) as the polar solvent. The obtained FeFe(CN)6/PEDOT-PSS nanohybrid offers discharge capacity 106.3 mAh⋅g–1, which is significantly higher than that of the naked FeFe(CN)6 (94.4 mAh⋅g–1). It also shown improved capacity retention and rate capability, which makes it a promising way for high performance Li-ion batteries for energy storage application. [ABSTRACT FROM AUTHOR]

Two 2,2,6,6-tetramethylpiperidinyl-N-oxy (TEMPO) contained polypyrrole (PPy) derivatives with the different side-chain length were synthesized by esterification of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radial with pyrrole butyric acid and pyrrole caproic acid. Then the homopolymers of 4-(3-(Pyrrol-1-yl)butyryloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-B-TEMPO) and 4-(3-(Pyrrol-1-yl)hexanoyloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-C-TEMPO) were prepared by chemical oxidative polymerization. The structure, morphology, electrochemical properties of prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-vis), scanning electron microscopy (SEM), cyclic voltammograms (CV) and electrochemical impedance spectra (EIS), respectively. Also, the charge-discharge properties of the prepared polymers were studied by galvanostatic charge-discharge testing. The results demonstrated that the as-synthesized nitroxide radical polymers showed a reversible two-electron redox reaction process in the potential limits of 2.5–3.0V and 3.4–3.8V vs Li/Li+, respectively. Under our experimental conditions, PPy only presented the discharge capacity of 16.5 mAh·g−1 at 20 mA·g−1 between 2.5 and 4.2V, while PPy-B-TEMPO with the short side-chain linked to TEMPO groups exhibited an initial discharge capacity of up to 86.5 mAh·g−1 with two well-defined plateaus. Furthermore, the PPy-C-TEMPO with the longer linking side-chain even displayed a discharge capacity of 115 mAh·g−1. These superior electrochemical performances were ascribed to the flexible linking side-chain and the introduction of stable conductive PPy main chain, which benefits the improvement of charge carrier transportation in the aggregated polymer bulk. [ABSTRACT FROM AUTHOR]

Abstract: Using polycarbonate (PC) as a matrix, and multi-wall carbon nanotubes (MWNTs) and acid-treated MWNTs (MWNTs-COOH) as fillers, PC/MWNTs and PC/MWNTs-COOH conductive composites were prepared, respectively. The conductive network formation induced by electric field in both the PC/MWNTs and PC/MWNTs-COOH composites were investigated by the dynamic percolation measurement. It was found that the electrical resistivity–time curves showed a certain self-similarity under various electric fields, i.e., the electrical resistivity decreased sharply as the percolation time (t p ) was reached. And the dynamic percolation time was shorten with the increase of the electric field intensity for both MWNTs and MWNTs-COOH filled PC composites. However, the percolation time and the formation activation energy of conductive network under electric field for MWNTs filled composites decreased greatly as compared to those of the MWNTs-COOH filled composites. These results indicated that the interaction between MWNTs and PC molecules played an important role in the conductive network formation under the electric field. Furthermore, the t p values under the electric field for PC/MWNTs and PC/MWNTs-COOH composites were successfully predicted by a modified thermodynamic percolation model. And this dynamic percolation measurement method could be recommended to investigate the zero-shear-rate viscosity at the different temperatures. [Copyright &y& Elsevier]

Abstract: In this work, LiFePO4/C composites were prepared in hydrothermal system by using iron gluconate as iron source, and two feeding sequences during the preparation were comparatively studied. The morphology, crystal structure and charge–discharge performance of the prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and galvanostatic charge–discharge testing. The results showed that the feeding sequences and iron gluconate seriously affected the microstructures and electrochemical properties of the resulting LiFePO4 cathodes in lithium ion batteries. The spindle-shaped LiFePO4 with hierarchical microporous structure self-assembled by nanoparticles has been successfully synthesized by synthesis route B. In addition, the cell performance of the synthesized LiFePO4 by synthesis route B was better than that of LiFePO4 by synthesis route A. Specially at high rates, the superior rate performance of the spindle-shaped LiFePO4/C microstructure (LFP/C-B) was revealed. And special reversible capacities of ∼118 and ∼95mAhg−1 were obtained at rates of 2C and 5C, comparing to ∼96 and ∼68mAhg−1 for LFP/C-A. [Copyright &y& Elsevier]

Abstract: An electrochromic copolymer based on 1,4-bis(3-hexylthiophen-2-yl)benzene (BHThBe) and perylene was electrochemically synthesized in dichloromethane (DCM) containing tetrabutylammonium perchlorate (TBAP) via the direct oxidation of BHThBe/perylene mixtures. The morphology and structure of as-prepared P(BHThBe–perylene) copolymer were characterized by SEM and FT-IR, respectively. The band gap energy (E g) of P(BHThBe–perylene) in the neutral state was calculated to be 2.03eV based on the onset of the second π–π* transition. The copolymer exhibited four different colors (brick red, grey brown, grey green, and black blue) during a wide potential ranging from 0.40 to 1.20V. Tunable electrochromism as well as smooth morphology made this copolymer a great candidate for many applications. [Copyright &y& Elsevier]

Abstract: Multiwalled carbon nanotubes (MWCNTs)-filled polycarbonate (PC), poly(vinylidene fluoride) (PVDF) and PC/PVDF conductive composites were fabricated using melt mixing, respectively. The dynamic process of MWCNTs conductive network formation in the composites was in situ traced by recording the variation of electrical resistivity with time during annealing treatments. As a result, the percolation threshold for the MWCNTs-filled PC/PVDF system was much lower than those of MWCNTs-filled individual polymers and the MWCNTs were selectively located in the PC phase of PC/PVDF composite, which had been verified by scanning electron microscopy measurements. The activation energy of conductive network formation for PC/PVDF/MWCNTs composite was close to that of the PC/MWCNTs system, which further confirmed that MWCNTs were dispersed mainly in the PC phase. Furthermore, the assembly velocity of MWCNTs in the polymer melt increased with annealing temperature. [Copyright &y& Elsevier]

Abstract: A novel amperometric glucose biosensor based on the nanocomposites of multi-wall carbon nanotubes (CNT) coated with polyaniline (PANI) and dendrimer-encapsulated Pt nanoparticles (Pt-DENs) is prepared. CNT coated with protonated PANI is in situ synthesized and Pt-DENs is absorbed on PANI/CNT composite surface by self-assembly method. Then Glucose oxidase (GOx) is crosslink-immobilizated onto Pt-DENs/PANI/CNT composite film. The results show that the fabricated GOx/Pt-DENs/PANI/CNT electrode exhibits excellent response performance to glucose, such as low detection limit (0.5 µM), wide linear range (1 µM–12 mM), short response time (about 5 s), high sensitivity (42.0 µA mM−1 cm−2) and stability (83% remains after 3 weeks). [Copyright &y& Elsevier]

Two types of acrylate rubber (AR)-based damping blends were prepared by using two types of phenolic resins (PF), a resole resin (RR) and a novolac resin (NR), as organic fillers. The structure and damping properties of the AR/RR and AR/NR blends obtained by hot-pressing were characterized and compared by Fourier transform infrared spectrum, scanning electron microscopy, differential scanning calorimetry, and dynamic mechanical analysis. The results showed that the chemical structures of PF and the hot-pressing process had a significant effect on the damping properties of the AR-based composites. The loss peak of AR/RR shifted to a lower temperature accompanied with a gradually reduced peak intensity with the increase of RR content. In contrast, hot-pressed AR/NR showed great improvement in damping properties, which can broaden the effective damping temperature region and an increase in the temperature of the loss peak. It was thus concluded that NR with linear structure and abundant phenolic hydroxyl groups, which can create effective hydrogen bonds with an AR matrix, even after hot-pressing, makes it a promising NR to choose as an organic additive in ARs to prepare advanced damping blends. [ABSTRACT FROM PUBLISHER]

Abstract: A novel ferrocene-contained pyrrole, 4-(1H-pyrrol-1-yl) phenyl ferrocenecarboxylate (FcPy) was synthesized by esterification of 4-(1H-pyrrol-1-yl) phenol (PLPY) and ferrocenecarboxylic acid. Then the homopolymer of FcPy (PFcPy), copolymer of FcPy and pyrrole (P(FcPy-co-Py)), polypyrrole (PPy) were prepared by chemical oxidative polymerization. And the structure, morphology, electrochemical properties of prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), cyclic voltammograms (CV) and electrochemical impedance spectra (EIS), respectively. Also, the charge/discharge properties of the prepared polymers were studied by galvanostatic charge–discharge testing. The results demonstrated that the introduction of ferrocene to polypyrrole obviously improved the specific capacity of PPy cathode and gave a well-defined plateau at the potential rang of about 3.5V. Under our experimental conditions, the discharge capacity of undoped PPy-based electrodes only presented 16.5mAhg−1 at 20mAg−1 between 2.5 and 4.2V, while PFcPy-based electrodes exhibited an initial discharge capacity of up to 43.2mAhg−1. Specially, the P(FcPy-co-Py)-based electrodes even showed a discharge capacity of 68.1mAhg−1 and the improved discharge platform, which were ascribed to the resonance doping effect of pendant group, the advanced electrochemical nature of ferrocene moiety and the loose morphology of copolymer. [Copyright &y& Elsevier]

The knowledge of the chemical stability of few-layer InSe nanosheets is important for its potential practical device applications. Here, the degradation characteristics of the as-exfoliated ultrathin InSe are studied through Raman spectroscopy. Under the laser excitation of 1 mW, very fast laser-induced degradation has been demonstrated. Moreover, it is found that fewer layered InSe is unstable even after exposure to air for a few hours. The oxidation products during the degradation process are also carefully examined, which are shown to be In 2 Se 3 and In 2 O 3. • The stability of few-layer InSe nanosheets was studied by Raman spectroscopy. • Higher excitation laser power would greatly accelerate the oxidation. • Fewer layered InSe are more readily oxidized under environmental conditions. • The oxidation products are In 2 Se 3 and In 2 O 3. [ABSTRACT FROM AUTHOR]

Abstract: A novel LiFePO4/graphene/carbon composite as a performance-improved cathode material for lithium-ion batteries had been prepared by using an in situ solvothermal method to synthesize LiFePO4/graphene powders as precursors and then followed by a carbon-coating process. The prepared samples of LiFePO4/graphene/carbon was investigated comparatively with LiFePO4/carbon and LiFePO4/graphene composites by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and various electrochemical testing techniques. The results indicated that the co-modification of LiFePO4 with graphene and carbon coating could construct an effective conducting network, which significantly enhanced the electrochemical activity of LiFePO4/carbon based composite. Particularly, the LiFePO4/graphene/carbon composite with a low content of graphene exhibited a high initial discharge capacity of 163.7mAhg−1 at 0.1C and 114mAhg−1 at 5C, as well as an excellent cycling stability. [Copyright &y& Elsevier]

Abstract: A novel amperometric biosensor based on self-assembling glutamate dehydrogenase (GLDH) and poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-PAMAM) onto multiwall carbon nanotubes (CNTs) has been developed for the determination of glutamate. The formation of the self-assembled (GLDH/Pt-PAMAM) n /CNTs construction was investigated by ζ-potential and high resolution transmission electron microscopy (HRTEM). The results indicated the uniform growth of the layer-by-layer nanostructures onto carboxyl-functionalized CNTs. The electrocatalytic property of the (GLDH/Pt-PAMAM) n /CNTs modified electrode to glutamate in presence of NAD+ (β-nicotinamide adenine dinucleotide, 0.1mM) was investigated at a low overpotential 0.2V by electrochemical measurements. The results showed it had series of attractive characteristics, such as a large determination range (0.2–250μM), a short response time (within 3s), a high sensitivity (433μA/mM−1 cm2) and good stability (85% remains after 4 weeks). [Copyright &y& Elsevier]

Electrode material is a key factor for high-energy storage battery. In this paper, graphene oxide/poly(o-phenylenediamine) (GO/PoPD) hybrid composite is prepared by combining the self-assembly process to form graphene oxide/o-phenylenediamine hydrogel and subsequently the in situ oxidation polymerization, which exhibits the open porous morphology with high BET surface area of 347 m2/g. As the anode of lithium ion battery, GO/PoPD possesses the double lithium storage mechanisms from graphene oxide and poly(o-phenylenediamine). Meanwhile, it exhibits an initial discharge-specific capacity of 1632.4 mAh/g and the improved cycling stability. Even after 43 cycles, it still keeps a capacity of 839.5 mAh/g, which is obviously higher than that of GO and PoPD. Furthermore, GO/PoPD hybrid composite presents the enhanced rate performances with the discharge-specific capacities of 1411.7, 718.2, 621.2, and 576.3 mAh/g at current rates of 50, 100, 200, and 500 mA/g, respectively. The improved electrochemical performances are attributed to the formed stable porous morphology, which facilitates the electrolyte ion to penetrate into the electrode matrix during the redox reaction and then results in the improved cell performances. [ABSTRACT FROM AUTHOR]

The Li (tri-(4-carboxyphenyl) amine) (Li-TCPA 2) doped polypyrrole (PPy-Li-TCPA 2) composites were successfully prepared by in-situ chemical oxidation using pyrrole and Li-TCPA 2 as raw materials. The structure, morphology, electrochemical properties of prepared materials were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), specific surface area test (BET), scanning electron microscopy (SEM), cyclic voltammogram (CV) and electrochemical impedance spectra (EIS), respectively. Also, the charge-discharge properties of the prepared composites were studied by galvanostatic charge-discharge testing. The results demonstrated that as-prepared composite material exhibited a reversible redox process at 2.0–4.0 V. And the discharge specific capacity for PPy-Li-TCPA 2 (2:1) and PPy-Li-TCPA 2 (6:1) are 50.4 mAh·g−1 and 63.7 mAh·g−1 as measured at 30 mA·g−1 between 2.0 and 4.0 V, while PPy-Li-TCPA 2 (4:1) exhibited the discharge specific capacity of 91.1 mAh·g−1, which were remarkably higher than that of the pure PPy (29.5 mAh·g−1) under the same experimental conditions. At the same time, PPy-Li-TCPA 2 (4:1) has improved rate performance and stable cycleability. The excellent electrochemical properties are attributed to the introduction of Li-TCPA 2 as dopant, which improved the electrical conductivity and the redox activity of PPy. Furthermore, the resulted well-dispersed particle structure of the composite as well as its improved specific surface area for doped PPy facilitated to the contact of the electrolyte with the active material, leading to the increased utilization ratio of active material and the enhanced electrochemical performances. The doped polypyrrole (PPy-Li-TCPA2) composites with Li (tri-(4-carboxyphenyl) amine) (Li-TCPA2) as novel dopant were firstly prepared by in-situ chemical oxidation. The charge-discharge properties of the prepared composites as the cathode material were studied in detail. The results demonstrated that as-prepared composite material exhibited a reversible redox process at 2.0–4.0 V. And the discharge specific capacity for PPy-Li-TCPA2 composites was obviously improved, specially PPy-Li-TCPA2 (4:1) sample exhibited the discharge specific capacity of 91.1 mAh·g−1, which were remarkably higher than that of the pure PPy (29.5 mAh·g−1) under the same experimental conditions. Furthermore, PPy-Li-TCPA2 (4:1) has improved rate performance and stable cycleability. The excellent electrochemical properties are attributed to the introduction of Li-TCPA2 as dopant, which improved the electrical conductivity and the redox activity of PPy. Furthermore, the resulted well-dispersed particle structure of the composite as well as its improved specific surface area for doped PPy facilitated to the contact of the electrolyte with the active material, leading to the increased utilization ratio of active material and the enhanced electrochemical performances. Unlabelled Image • PPy-Li-TCPA 2 composite was prepared. • It was studied as organic cathode material. • PPy-Li-TCPA 2 (4:1) exhibited improved cell performances. [ABSTRACT FROM AUTHOR]

In the present work, the poly(o-phenylenediamine)/Ag (PoPD/Ag) hybrid composite with the microrod morphology was prepared by in situ chemical oxidation method, and then composite electrodes of PoPD/Ag (PVDF) and PoPD/Ag (sodium alginate) were prepared by using PVDF and sodium alginate as electrode binders, respectively. As explored as the anode of lithium ion batteries, the redox-active PoPD in the hybrid composite, compared to the pure PoPD, demonstrated the remarkably improved electrochemical performances with superior high capacity and good rate capability and cycling stability, due to the improved intrinsic electrical conductivity of PoPD via the introduced Ag nanoparticles in the polymer. As the sodium alginate was chosen as the functional electrode binder, PoPD/Ag (sodium alginate) exhibited the initial charge/discharge-specific capacity of 1452.9/2317.7 mAh g−1, and after the 100th cycles, the developed discharge capacity for PoPD/Ag (sodium alginate) reached to 1389.9 mAh g−1, which was evidently higher than that of PoPD. Its stable and representative discharge-specific capacities were 1291, 1044.9, 856.7, 762.5 mAh g−1 at the current rate of 50, 100, 200, and 500 mAh g−1, respectively, which were obviously superior to that of PoPD and PoPD/Ag (PVDF), indicating that sodium alginate as binder has the special effects on the electrochemical characteristics of PoPD, which benefited to the capacity release step by step during the charge/discharge process. The works would provide significant exploration for the preparation of high-performance poly (aromatic amine) polymer as the electrode materials. [ABSTRACT FROM AUTHOR]

A novel organic conjugated polymer based on star‐shaped triazine‐functional triphenylamine framework poly[1,3,5‐tris(4‐diphenylamino‐phenyl)triazine] (PTDAPTz) is designed and synthesized successfully by FeCl3‐catalysted chemical oxidative polymerization. The polymer PTDAPTz powder exhibits a compactly packed pleated skirt shape‐like morphology with a high surface area (~930 m2 g−1) and a bimodal pore size distribution ranging from micropores (~0.55 nm) to small diameter mesopores (~2–6 nm). As explored as the cathode material, the obtained PTDAPTz presents the double charge–discharge process characteristics of both the free radical redox of triphenylamine unit and the bipolar redox of triazine unit in the polymer and a well‐defined multistage charge/discharge voltage plateau (~3.8 V for p‐doped and ~2.0 V for n‐doped) during the charge–discharge process. Also, the PTDAPTz demonstrates an improved capacity (stabilized at 123 mA h g−1 until 50th cycle) and the enhanced rate performance compared to polytriphenylamine (PTPAn). Specially, the discharge curve for the part of triphenylamine unit presents an obviously improved discharge plateau (~3.8 V for PTDAPTz compared to ~3.6 V for PTPAn) due to the electron‐withdrawing effect of the triazine unit to triphenylamine. The elaborate structural design and created micro‐/mesoporous morphology with the double charge–discharge process make PTDAPTz a potential candidate as the performance‐improved cathode of Li‐organic battery. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2574–2583 A novel conjugated microporous polymer based on star‐shaped triphenylamine‐triazine framework PTDAPTz was designed and synthesized simply, and the powder exhibited a pleated skirt shape‐like morphology (the sliced layer thickness of ~30 nm) with high surface area (~930 m2 g−1) and micropores of diameter of ~0.55 nm as well as mesopores of ~2–6 nm. As the cathode of an Li‐organic battery, the polymer PTDAPTz presented double charge–discharge characteristics, thus improving the voltage platform of the batteries while simultaneously guaranteeing improved capacity. [ABSTRACT FROM AUTHOR]