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Analysis of neurotransmitters such as dopamine (DA) is essential to better understand brain-related mechanisms. In this context, paper-based electroanalytical devices are promising alternatives to the current techniques for affordable, user-friendly molecular quantitation. Conductive carbon-based and polymer-based inks such as carbon nanotubes (CNT) and polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) have shown several advantageous properties, such as resistance to the DA fouling occurring during the electrochemical detection. Here, the electrical and electrochemical properties of paper devices prepared from mixtures of the inks were investigated, as well as their DA detection performance (limit of detection and fouling resistance). The properties of these paper electrodes were found to be directly impacted by the choice of ink. CNT-based electrodes are more resistive than the PEDOT:PSS based ones, which are more capacitive. Also, electrodes with undercoats of CNT and overcoats of PEDOT:PSS, doped with organic solvents, better resist DA fouling and have lower limits of detection. The combination of carbon-based and polymer-baser inks allowed for optimizing DA detection, and highlights the versatility and adaptability of paper-based electrode fabrication. [ABSTRACT FROM AUTHOR]

Due to highly conducting and extraordinary stable nature, carbon based materials expand the arms of energy storage devices in terms of supercapacitor. Hence, emphasis has been made to use flexible and free-standing multi-walled carbon nanotubes (MWCNTs) bucky paper synthesized by chemical vapor deposition for electrochemical supercapacitive electrode. The high specific capacitance of 270 F/g (2 mV/s) with superb stable behavior (88% at 10000 cycles) of bucky paper has promised as decent electrode in energy storage application. Aqueous symmetric supercapacitor (ASSC) device developed through bucky paper exhibits voltage frame of 1.6 V yielding specific capacitance of 91 F/g along with specific energy of 32 Wh/kg at a current density of 1 mA/cm 2 with trustworthy stability of 107% at 6000 cycles. The hands-on practicability to light up a red LED offers its promising approach in energy storage domain. [ABSTRACT FROM AUTHOR]

A novel polyprrole (PPy)-decorated hierarchical NiCo 2 O 4 nanoneedles was grown on highly conductive carbon fiber paper (CFP) for high performance asymmetric supercapacitor applications. The PPy-decorated hierarchical NiCo 2 O 4 nanoneedle on CFP (PPy-NiCo 2 O 4 @CPF) was grown by two steps. At first, NiCo 2 O 4 nanoneedle was grown by hydrothermal process and followed by the deposition of PPy through electrochemical method. The fabricated PPy-NiCo 2 O 4 @CPF electrode displayed the higher electrochemical performance. The specific capacitance was ∼910 F g-1 at a current density of 1 A g −1 and cyclic stability was ∼88% after 10,000 cycles. To explore real performance of the electrode, we have fabricated solid state asymmetric supercapacitor using PPy-NiCo 2 O 4 @CFP as positive and nitrogen doped reduced graphene oxide (N-rGO) as negative electrodes. The fabricated asymmetric device delivered a specific capacitance of 118.6 F g-1 at a current density of 1.0 A g −1 with a maximum energy density of 40.81 Wh Kg −1 (at a power density of 738.27 W Kg −1 ) and maximum power density of 3746.77 W Kg −1 (at an energy density of 13.53 Wh Kg −1 ). The impressive results suggest that flexible PPy-NiCo 2 O 4 @CFPs can be a promising electrode material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Cellulose paper-based energy storage devices have spurred significantly intrinsic advantages compared with the traditional batteries due to environmental benignity, recyclability and easy processing. In this work, the binary functional materials, which contains linear N-doped carbon nanotube (N-CNT, one-dimensional) and spherical C-coated MoS 2 (MoS 2 @C, zero-dimensional), are embedded into the porous recycled paper (RP, two-dimensional) derived from wastepaper via a facile and low-cost vacuum filtration method, and then the N-CNT/MoS 2 @C/RP film (N-M-RP film) featuring a unique compacted “point-line-plane” structure is obtained. In favor of the synergistic effect of high-conductive N-CNT, high-capacity MoS 2 @C and porous RP network, the prepared freestanding N-M-RP film presents a high strength of 35.2 MPa and a comparably low sheet resistance of 127.39 Ω sq −1 , and as an anode material for LIBs, the N-M-R film delivers a high reversible capacity, good cycling performance, superior rate capability and excellent electrochemical kinetics. Besides, the synergistic effect of “point-line-plane” structure on the improved electrochemical performances is also investigated. All the results indicate that the N-M-RP film comprised of 0D-1D-2D materials could be a potential candidate as a freestanding anode for LIBs. [ABSTRACT FROM AUTHOR]

• Variation of Young's modulus of Ga in the process of discharge (lithiation) was measured. • Self-healing ability of EGaIn to automatic repair the cracks resulted from charge/discharge. • The CNF/CNT@EGaIn NPs anode is free-standing, flexible and binder-free. Gallium-based liquid metals are considered as potential anode materials for lithium-ion batteries owing to their self-healing, non-poisonous advantages, as well as high theoretical capacity. However, due to the alloying/dealloying reaction mechanism to store lithium, Gallium-based alloys face huge volume change resulted in poor cycle life. Furthermore, the poor wettability of liquid metals on many kinds of substrates (carbon materials, stainless steel, etc.) and their strong ability to form alloys with many metallic current collectors (Cu, Al foil) make them hard to be designed into electrode with excellent electrochemical performance. One objective of this paper is to investigate Young's modulus of Ga discharged to different cut-off potentials, in order to gain a further understanding of mechanical property attenuation of Ga in the process of lithiation. Moreover, a three-dimensional (3D) free-standing electrode is fabricated by confining Ga-based liquid metal, EGaIn, in the matrix of carbon nanofibers/carbon nanotubes paper (CNF/CNT@EGaIn NPs). The network structure provides effective pathways for electrons and ions, as well as enough space to contain the volume expansion of EGaIn. The dense CNT layer plays a further role on preventing EGaIn from shedding of the conductive substrates. Obtained CNF/CNT@EGaIn NPs exhibits a good ionic/electronic conductivity and mechanical stability, delivers capacity of 351 mAh g−1 at 1.6 A g−1 and remains a reversible capacity of ∼420 mAh g−1 after 100 cycles at 800 mA g−1. This work could provide valuable insights into the development of Ga-based liquid metal anodes. [ABSTRACT FROM AUTHOR]

Multi-wall carbon nanotubes (MWCNTs) have been synthesized on a carbon fiber paper (CFP) via a simple surface reaction of hydrocarbon decomposition using nickel nanoparticles as catalysts at 1023 K. Pd nanoparticles supported on MWCNTs/CFP are used as electrocatalysts for ethanol electrooxidation in alkaline media. The results shows that the Pd/MWCNTs/CFP electrocatalyst gives higher reaction activity and more stable performance than the commercial Pd/C and Pd/CFP electrocatalyst for ethanol oxidation in alkaline medium. [ABSTRACT FROM AUTHOR]

Tin oxide/Multi Walled Carbon nano tube nanocomposite (SnO 2 /MWCNT) is synthesized using ethylene glycol mediated industrially viable simple process. Binder free, self-supporting and flexible SnO 2 /MWCNT nanocomposite paper has been prepared by employing the vacuum filtration technique. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS), and thermal gravimetric analysis (TGA) to evaluate the structure of anode and tested for its performance in a Lithium rechargeable cell. Electrochemical measurements demonstrate that the SnO 2 /MWCNT composite paper anode with 30% of SnO 2 by weight delivers a specific discharge capacity of ∼420 mAh g −1 up to the investigated 50 cycles at a current density of 100 mA g −1 which is ∼200 % increase in capacity as compared to pristine MWCNT anode tested under similar conditions. The application of the developed anode is demonstrated by fabricating a lithium ion pouch cell. [ABSTRACT FROM AUTHOR]

• 3D integrated Sn/CNT@N C gas diffusion electrode is proposed by phase inversion. • CNT@N C has integrated sponge-like microporous and finger-like macroporous layers. • The co-catalysis of N improves electron-proton-gas transfer for high performance. • Faraday efficiency of formate and CO is improved compared with Sn/carbon paper. A 3D integrated hierarchical porous N-doped Sn/CNT@N C gas diffusion electrode is proposed via phase inversion to synergistically improve electron-proton-gas transfer and efficiency of CO 2 reduction reaction (CO2RR). Hierarchical porous structure is tuned by the carbon nanotube additive during phase inversion, which integrates microporous layer and diffusion layer to decrease mass transfer resistance comparing with the 2D layer structure of commercial carbon paper. XPS results show that Sn/CNT@N C 800 contains pyridinic nitrogen and pyrrolic nitrogen with catalytic activity. EIS and LSV curves show that Sn/CNT@N C 800 is beneficial to reduce mass transfer resistance and increase current density after twice hydrophobic treatments. As a result, Sn/CNT@N C 800 shows higher CO 2 RR electrocatalytic activity. The reaction rate and Faraday efficiency of CO at 12 mA cm−2 increase by 40.2% and 40.6%, respectively compared with Sn/carbon paper. The reaction rate and Faraday efficiency of formate are also slightly higher than those of Sn/carbon paper. [Display omitted] [ABSTRACT FROM AUTHOR]

• A columnar liquid-crystalline triazine-based dendrimer has been incorporated as Li-ion battery anode. • The additional 1% carbon filler (CNT paper) in the triazine-based anode successfully boost the battery performance. • Systematical spectroscopic studies reveal that Li+ insertion in triazine and piperazine functional groups plays an important role in the Li+ storage mechanism. • The charge storage evaluation and kinetical studies unleashed the role of carbon filler on boosting capacitive contribution and accelerating Li+ transport. Owing to their highly tunable molecular structure and chemical stability, dendrimers consisting of triazine and piperazine moieties have been investigated. The present work describes the electrochemical performance of a columnar liquid-crystalline triazine-based dendrimer containing the linker with diaminopropane (DAP) as a lithium-ion battery anode. To elucidate the impact of conductive carbon filler in the electrode, a tiny amount of carbon nanotube (CNT) paper has been incorporated in the DAP anode. The battery performance revealed that the DAP anode has shown a high specific capacity of up to 444 mA h g−1 at 0.5 A g−1 after 200 cycles. Surprisingly, with an additional 1% CNT, the Li+ storage capacity of the dendrimer-based composite anode (DAP/CNT1%) significantly enhanced up to 656 mA h g−1. To the best of our knowledge, this is the first time that a triazine-based dendrimer has been utilized as an anode material in conjunction with a small amount of CNT to further boost its energy-storing capabilities through a synergy of capacitive storage mechanisms and improve Li+ transport. The efficient lithium storage of DAP/CNT composite further shows its amenability as organic electrode material for next-generation organic Li-ion batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

One of the major challenges towards the development of the conventional alkaline Zn-air battery is its spontaneous discharge caused by the unstability of the anode Zn in concentrated alkaline electrolyte. Utilization of a neutral electrolyte as the alternative to alkaline electrolyte is likely to be a promising strategy to overcome this issue because of much high stability of anode Zn in neutral solution. To realize the normal operation of the neutral Zn-air battery however, a crucial issue is how to ensure that the cathodic catalyst can efficiently electro-catalyze oxygen reduction reaction (ORR) in neutral solution. Herein, we report a facile preparation of Ni/Co-doped C-N nano-composite catalysts (NiCo/C-N) from direct pyrolysis of Ni/Co salt, polyaniline (PANI), carbon nanotube (CNT) and dicyandiamide. Among the as-synthesized catalysts, Ni 1 Co 3 /CN-3 presents high and stable ORR current density of 5.27 mA cm −2 in 0.5 mol L −1 KNO 3 solution at 2000 rpm. Electron transfer number of ORR on Ni 1 Co 3 /CN-3 catalyst is 3.78, showing a nearly completed reduction of O 2 to H 2 O. A neutral Zn-air battery with the prepared NiCo/C-N composite coated on carbon paper as the air electrode catalyst and metal Zn as the anode was constructed in 0.5 mol L −1 KNO 3 solution. For the catalyst Ni 1 Co 3 /CN-3, the open circuit voltage of the neutral Zn-air battery is 1.16 V, and the maximum power density is 38.5 mW cm −2 . The galvanostatic discharge time is 345.7, 160.6, 18.1 and 1.3 h as the discharge current density keeps 10, 50, 100 and 150 mA cm −2 respectively. A stable voltage plateau arises at various discharge current densities. The neutral Zn-air battery can repeatedly discharge after the zinc anode has been replaced, indicating that the synthesized ORR catalyst is an excellent cathode material for the neutral Zn-air battery. This kind of neutral Zn-air battery has a wide application prospect as mobile power supply. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide/carbon nanoparticles (RGO/CNs) composite films with good flexibility and high mechanical strength were prepared via a facile hydrothermal process of the β-cyclodextrin modified graphene oxide (β-CD/GO) hydrogel in presence of ascorbic acid (vitamin C), in which the GO was reduced into reduced graphene oxide (RGO) and β-CD converted into carbon nanoparticles (CNs). The resulted CNs could enlarge the interlayer distance of graphene sheets not only to prevent their agglomeration, but also to improve the transfer speed of the electrolyte ions throughout the film electrodes during the charge/discharge process. The flexible and robust RGO/CNs composite films were then used as highly conductive supports for the electrodeposition of polyaniline (PANI) to further improve the electrochemical performance. As flexible and robust paper-like electrodes, the reduced graphene oxide/carbon nanoparticles/polyaniline (RGO/CNs/PANI) composite films exhibited high electrochemical activity, such as high specific capacitance of 787.3 F/g at the current density of 1 A/g and 564.0 F/g at the current density of 10 A/g, as well as excellent cyclic stability. The results demonstrated the significant potential application of the proposed RGO/CNs/PANI composite films as binder-free and free-standing electrodes for high-performance flexible energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, Pt-Pd alloy catalyst was fabricated on carbon papers via electro-deposition as an alternative catalyst for oxygen reduction in air-cathode Microbial Fuel Cells (MFCs). Effects of electro-deposition cycles and supporting materials (graphene and carbon nanotubes (CNTs)) on oxygen reduction reaction (ORR) activity of the Pt-Pd electrode and power generation in MFCs were investigated. The structural and electrochemical properties of the Pt-Pd catalyst were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results showed that the Pt-Pd electrode showed a good ORR activity. A MFC with a Pt-Pd cathode of 15 deposition cycles produced a maximum power density of 1274 mWm −2 , comparable to that with a conventional Pt/C cathode (0.5 mg Pt cm −2 ). CNT as the supporting material further increased ORR activity of the Pt-Pd electrode and power generation capacity in MFCs, while graphene as the supporting material did not produce positive effects. XRD results confirmed the presence of Pt/Pd elements on the electrode. SEM results showed that decoration using CNT reduced Pt-Pd particle size and promoted them even dispersion on the carbon paper. The Pt-Pd electrode attained a comparable performance to the Pt/C electrode when controlling an optimum deposition cycles and using CNT as the supporting materials, which demonstrates the potential of replacing Pt as an oxygen reduction catalyst in MFCs due to high oxygen reduction activity and relatively low cost. [ABSTRACT FROM AUTHOR]

In this paper, (NH 4) 2 V 4 O 9 nanosheets coexisting with carbon nanotubes were prepared by hydrothermal method as cathode materials for aqueous zinc ions, which can improve the electrochemical performance of the battery. The structure, morphology and electrochemical properties of (NH 4) 2 V 4 O 9 /CNTs were studied and analyzed by physical characterization and electrochemical tests. Carbon nanotubes coexisting with (NH 4) 2 V 4 O 9 provide an electron transfer channel, significantly improving the rate performance of the material. The discharge specific capacity of (NH 4) 2 V 4 O 9 /CNTs is 445 mAh g −1 at a current of 0.1 A g −1; while the discharge specific capacity still remains 207.16 mAh g −1 when the current up to 5.0 A g −1. After 2000 cycles at a high current density of 10 A g −1, the discharge specific capacity of the battery remained 93.1 mAh g −1 from 115.2 mAh g −1 in the first cycle, showing good cycle performance. Therefore, (NH 4) 2 V 4 O 9 /CNTs has fast charge-discharge performance and cycle stability. [ABSTRACT FROM AUTHOR]

• Almost all the Al-ion batteries' cathode materials were evaluated with the approach. • The normalization/standardization approach was applied to the charge-discharge data. • The carbon-based cathodes present excellent performance and rate-capability. • The cathode substrate plays role in the properties. • The electrolyte type affects the activity of the cathode particles. The improvement of the intercalation electrodes for Al-ion batteries needs a deep understanding of the relation of charge-discharge parameters, especially the specific capacity (C) and the charge-discharge rate (R). In this paper, we extract many experimental charge-discharge data (C and R) from the literature. Evaluating the data, we employ an approach which has been proposed for the normalization and standardization of the intercalation batteries' data. The approach presents an appropriate manner for assessing the goodness of a given electrode and cell performance. The data of Al-ion batteries' electrode materials show more distribution in comparison with Li-ion and Na-ion batteries. We find that the distribution of the curves is due to three main parameters, namely synthesis method, electrolyte type, and substrate of the electrode. It is found that among the considered materials the carbon-based electrodes including graphene, carbon nanotube, and graphite provide the best performance and rate-capability, while the MoS 2 electrode shows the poorest one. It is concluded that (de)intercalation of AlCl 4 − ions has a faster kinetic than Al3+ ions. Accordingly, an insight for the perspective of the future researches of the intercalation batteries is suggested. This study helps finding appropriate materials (electrode, electrolyte, and substrate), and paves the way for optimization of the cells. Noteworthy, this paper is vanguard for this kind of evaluations and its methodology can be used for other kind of cells and electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract In this paper, we first report the ultrasonic dispersion temperature- and pH-tuned spectral and electrochemical properties of bovine serum albumin (BSA) on single-walled carbon nanotubes (SWCNTs) and its configurational transition. The BSA-SWCNTs exhibit an irreversible oxidation peak at 0.793 V (vs. SCE) and a couple of tryptophan (Trp)-based surface-confined redox peaks at the formal potential of 0.154 V. The decrease of the dispersion temperature down to 283 K from 313 K at pH 7.2 leads to an increase in the surface activity coefficient (γ s) and exothermic reaction rate constant (k f). The loop (L)-shaped BSA-SWCNTs with slight β -sheet prepared by controlling the dispersion temperature at 298 K (pH 7.2) show the maximum emission and minimum absorbance. The L-form of BSA-SWCNTs is transformed into basic (B)-form and fast migration (F)-form while controlling the dispersion temperature at 283 K and 313 K, respectively. The dispersion temperature and pH have a synergistic influence on the spectral and electrochemical properties of BSA-SWCNTs via the unfolding/refolding processes of β -sheet driven by ultrasonic/thermal motion and surface adsorption. The present study provides an effective approach for the preparation and evaluation of serum protein-based nanomaterials with spectral and electrochemical properties tuned by dispersion pH or temperature, as well as opens the way for optoelectronic and electrochemical applications. Graphical abstract Image Highlights • BSA-SWCNTs show tunable electrochemical and spectral properties by pH and T. • BSA-SWCNTs show B-form (283 K), L-form (298 K) or F-form (313 K) at pH 7.2. • L-form of BSA-SWCNTs exhibit maximum emission and minimum absorbance. • BSA-SWCNTs are involved in Trp-based oxidation to form redox-active centers. • Dispersion T and pH have synergistic effects via β -sheet unfolding/refolding. [ABSTRACT FROM AUTHOR]

• CO 2 electroreduction catalyzed by VB12/CNTs was studied in KHCO 3 and ionic liquid. • The maximum CO Faraday efficiency was 95.98% in KHCO 3 and 99.29% in ionic liquid. • The current density of CO was 40.85 mA cm−2 at −0.86 V (vs. RHE) in 0.5 M KHCO 3. • The Co center of VB12 was the main active site verified by in situ Raman spectra. Electrocatalytic CO 2 reduction reaction (ECO 2 RR) has attracted much attention for its ability to convert CO 2 into valuable chemicals. However, it is still a challenge to achieve high Faradaic efficiency (FE) and high current density (j) in ECO 2 RR simultaneously. Vitamin B12 (VB12) has been considered as a novel and highly effective catalyst for electrocatalytic reduction of CO 2 to produce CO in aqueous electrolyte, and carbon nanotubes (CNTs) have excellent conductivity. Herein, VB12/CNTs composites are deposited onto carbon paper by electrophoretic deposition. The prepared catalyst exhibits a high FE of CO (FE CO) as 95.98% and the corresponding j of CO (j CO) is 40.85 mA cm−2 at −0.86 V (vs. RHE) in 0.5 M KHCO 3 electrolyte. Moreover, FE CO is greater than 98% in the range from −2.0 V to −2.4 V (vs. Ag/Ag+), and the maximum FE CO is as high as 99.29% with a j CO of 65.53 mA cm−2 at −2.2 V (vs. Ag/Ag+) in ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF 6) electrolyte. In situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) demonstrates that the Co center of VB12 is the main ECO 2 RR active site. Density functional theory (DFT) calculations further indicate that the formation of COOH* is the rate-limiting step of the ECO 2 RR. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a polypyrrole/vertically aligned carbon nanotube (PPy/VACNT) composite has been prepared by in situ chemical polymerization of pyrrole precursor on the surface of VACNT electrode. VACNTs has been prepared by plasma enhanced chemical vapor deposition (DC-PECVD) from a mixture of H 2 and C 2 H 2 and were used as 3D nanoporous substrates. Effects of different dopant anions on the charge storage properties of PPy have been studied in this work. Camphor sulfonic acid, α-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate, Sodium dodecylbenzenesulfonate and sodium dodecyl sulfate were used as anionic dopants. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction were used to characterize the electrodes. Cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy technique in 1 M HCl electrolyte were applied to investigate the electrochemical properties of electrodes. The results showed the specific capacity of electrodes was found to be in the order of the mentioned dopants at 10 mV s −1 scan rate. A maximum specific capacity of 332 C g −1 was obtained with PPy/VACNT which was doped with camphor sulfonic acid at 10 mV s −1 scan rate. In addition, the specific capacity of this electrode increased during cycling in 1 M HCl electrolyte which shows excellent cyclic life. The results show PPy-CSA/VACNT composite electrode have excellent characters of an electrode as a consequence of porous network structure and high electrochemical conduction which provides straight and fast ion transport pathways. [ABSTRACT FROM AUTHOR]

ZnMn 2 O 4 is regarded as one of the potential anode materials for lithium-ion batteries (LIBs), due to its high theoretical specific capacity (784 mAh g −1 ). Unfortunately, the bulk ZnMn 2 O 4 presents an inferior electrochemical performance resulting from the large volume change during the charge-discharge process. In this paper, we report the synthesis and electrochemical properties of ZnMn 2 O 4 nanoparticles (NPs) that are homogeneously distributed in connective network porous carbon nanofibers wrapped by reduced graphene oxide sheets. The distinctive structure of this composite not only provides enough voids to storage Li-ions and buffer the volume expansion of the ZnMn 2 O 4 NPs, but also offers a continuous conducting network for Li-ion and electron transportation, resulting in significantly improved electrochemical performances. As binder-free electrodes for LIBs, an optimized ZnMn 2 O 4 @rGO-CNFs sample exhibits a reversible capacity of 1142 mAh g −1 at 100 mA g −1 over 100 cycles, and a stable capacity of 659 mAh g −1 after 1000 cycles at a large current density of 2000 mA g −1 , enabling ZnMn 2 O 4 a promising electrode candidate for LIBs. [ABSTRACT FROM AUTHOR]

As a new class of zero-dimensional (0D) carbon nanomaterial, graphene quantum dots (GQDs) have attracted increasing attentions due to their unique properties of both graphene and quantum dots. In this paper, GQDs-decorated hierarchical-like hollow NiCo 2 S 4 nanostructures are fabricated through simple two-step hydrothermal reactions. Compared with the bare NiCo 2 S 4 nanowires, it is found that the surface morphology and internal structure have been changed with the introduction of the GQDs during the similar growth process. The unique nanostructures have resulted in better electrochemical performance for supercapacitors, such as good rate capability, high specific capacitance (678.22 F g −1 at the current density of 0.2 A g −1 ) and enhanced cycling stability (94% retention after 5000 cycles), due to the lower impedance, larger specific surface area, more interspace and pathways for both ion diffusion and volume changes. These results show that the introduction of the GQDs during the fabrication process could be a feasible route to obtain novel nanostructures, and the GQDs decorated nanocomposites are promising for the development of next generation electrochemical devices. [ABSTRACT FROM AUTHOR]

Understanding the influence of synthesis parameters on morphology and electrochemical properties of carbon nanostructure is necessary for the development of application-tailored materials. We report on the synthesis by plasma enhanced chemical vapor deposition, morphology and catalytic activity towards oxygen reduction reaction (ORR) of hierarchical carbon nanowalls (hCNW) at different deposition times. hCNW are an advancement of common CNW possessing an increased surface area while retaining the ideal mass transport characteristics of common CNW. The hCNW structure results from a synthesis using p -xylene as an aromatic precursor. hCNW are non-doped and metal-free with easily accessible graphitic edge sites at the top of the walls and numerous defects sites located within the porous side walls, which are ideal sites for adsorption and electron transfer. hCNW reveal a high amount of different electrochemically active sites that dominate the material character depending on the deposition time. The hCNW exhibit excellent catalytic activity towards ORR with very high ORR onset potential of 830 mV vs RHE in 0.1 mol L −1 KOH solution and selectivity towards a two electron transfer mechanism. Thereby, the onset is higher than that of several nitrogen doped carbons and one of the highest for pure carbon electrodes. In contrast to other pure carbon materials with similar onsets, oxygen doping of hCNW before the experiments could be ruled out. As such, the results of this paper indicate the existence of inner sphere ORR on sp 2 -carbon. Additionally, the results emphasize the relevance of often overlooked material properties such as surface accessibility as well as electrical conductivity for ORR. [ABSTRACT FROM AUTHOR]

This paper represents a simple approach to modulate electrochromic properties of poly (4,4′-(1,4-phenylene)bis (2,6-diphenylpyridinium) triflate) (PV) by the formation of composite material with multiwalled carbon nanotubes. The polymer acts as a functionalizing agent for MWCNTs to prevent their agglomeration enabling the formation of stable dispersions. They were further used to prepare uniform electrochromic films by spin-coating method. The films were characterized by electrochemical and spectroelectrochemical methods. To evaluate the influence of MWCNTs on the electrochromic properties of PV the dispersions with various PV/MWCNTs compositions were studied. Upon the addition of MWCNTs the absorption bands and redox peak potentials of polymer did not change. However, the decrease of the peak separation between reductive and oxidative waves and the significant improvement of switching times (one of the most important properties of electrochromic materials) were demonstrated. At the practically identical optical contrast both coloration and bleaching times decreased that can be explained by the composite film morphology. This effect became significant for high PV concentrations in the initial solution. The decrease of coloration and bleaching times reached 30% and 50%, respectively. The resulting composite material exhibited fast (200–400 ms) response times and could be used as a promising candidate for novel electrochromic devices. [ABSTRACT FROM AUTHOR]

In this paper, we report a facile template-free method to prepare the T-Nb 2 O 5 /CNTs composite. The addition of ammonia induces the electrostatic interaction between functionalized CNTs and niobic acid colloids during hydrothermal process, resulting in CNTs homogeneously distributed in the T-Nb 2 O 5 phase. The obtained T-Nb 2 O 5 /CNTs composite shows high rate Li + storage ability with typical intercalation capacitive behaviour. The presence of well-dispersed CNTs in Nb 2 O 5 can apparently reduce the limitation from diffusion process and increase the high rate charge-discharge capability. From the galvanostatic tests, a capacity of ∼180 mAh g −1 at 1 A g −1 and ∼130 mAh g −1 at 5 A g −1 is attained. [ABSTRACT FROM AUTHOR]

Paper-like flexible electrode becomes one of the most important research objects in energy storage. In the present work, sandwich-structured S-doped reduced graphene oxide/carbon nanotubes/polyaniline (S-rGO/CNTs/PANI) composite membranes were designed as free-standing electrodes for high-performance supercapacitors, by electro-deposition of polyaniline (PANI) onto the flexible and robust sandwich-structured S-doped reduced graphene oxide/carbon nanotubes (S-rGO/CNTs) composite films as highly conductive supports, which were prepared through a mild hydrothermal reduction and doping reaction of graphene oxide (GO) nanosheets in presence of multi-walled carbon nanotubes (MW-CNTs), with Na 2 S as not only a sulfur precursor, but also a high-efficient reducing agent. The S-rGO/CNTs/PANI composite membrane electrode possessed high specific capacitance (812 F/g) in 1.0 M H 2 SO 4 aqueous solution, with excellent rate capability and cycling stability for supercapacitors without the need of current collectors and binders, showing significant potential in flexible energy storage devices. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials-loaded mixed metal oxides are the promising candidates to increase the electrochemical efficacy for glucose monitoring. In this paper, we developed a new hybrid material based on multi-walled carbon nanotubes-supported nickel and cerium mixed oxide nanocomposite (NiCeO x /MWCNTs) through one pot hydrogen co-reduction strategy for non-enzymatic electrochemical glucose sensing. The microscopic and spectroscopic features of as-prepared samples were thorougly characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Further, cyclic voltammetry (CV) and chronoamperometry (CA) methods were applied to investigate the electrochemical efficacy of designed electrode towards glucose sensing. The results revealed that, the synergetic effect of nickel and cerium mixed oxides as well as brilliant conductivity of MWCNTs collectively enhanced the electrocatalytic activity of the designed materials for glucose oxidation. Therefore, the fabricated NiCeO x /MWCNTs-based sensor retains the excellent electrochemical efficacy towards glucose sensing as compared to their counterparts including wider linear range (0.007∼0.466 mM and 0.466∼3.44 mM), lower limit of detection (1.8 μM, S/ N = 3), satisfactory sensitivities (271.53 and 429.95 μA mM−1 cm−2) as well as good reproducibility, high stability and selectivity. More specifically, the designed NiCeO x /MWCNTs-based sensor offered brilliant real time applicability to precisely monitor glucose level in diluted human serum samples. This study provided an appealing strategy for the development of simple, efficient and cost-effective non-enzymatic electrochemical glucose sensing platform. [Display omitted] [ABSTRACT FROM AUTHOR]

• Systematic study of 3d transition metal-doped CNTs. • V(Cr, Mn, Co)-doped CNTs show spin-polarization effects. • The 3d transition metal doping makes a big difference to the energy band. • 3d transition metal doping increases the quantum capacitance. • Ni-CNT has the largest quantum capacitance near zero potential. Supercapacitors are valued as one of the new green energy storage devices, but the low energy density limits the wide application of supercapacitors. In this paper, the effects of 3d transition metal doped on electronic structure and quantum capacitance of carbon nanotubes are investigated using DFT. The calculations show that elemental doping has caused the break-up of two degenerate states near the Fermi level, quasi-local state changes in the energy band, and the creation of new energy bands. The doping of V(Cr, Mn, Co) causes spin polarization in the energy band. The change in energy band affects the density of states near the Fermi level, effectively increasing the quantum capacitance and surface charge density of the carbon nanotube electrode. The quantum capacitance of Ni-doped carbon nanotubes is the largest, at 59.74 µF/cm2. In the range of water stability, Ti(V, Gr, Mn, Co)-CNT are suitable for use as electrode materials in symmetrical double layer supercapacitors. Sc(Fe, Cu, Zn)-CNT is suitable for use as anode materials in asymmetric double layer supercapacitors. Ni-CNT is suitable for use as a cathode material for asymmetric double layer supercapacitors. This study verifies the feasibility of 3d transition metal doping to improve the quantum capacitance of carbon nanotube electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of novel nanocomposite based on multi-walled carbon nanotubes (MWCNT) covalently bonded by molecularly imprinted poly(methacrylic acid-hemin) (MIP-MWCNT) using tert-butylhydroquinone (TBHQ) as template molecule and its use in the construction of electrochemical sensor. Chemical, physical and morphological structure of nanocomposite was characterized by FT-IR, TGA, SEM, TEM and textural analysis. The electrochemical sensor highly selective to TBHQ was prepared by drop-casting a suspension of nanocomposite on the surface of a glassy carbon electrode. From cyclic voltammetry, it was observed that the electrochemical sensor modified with MIP-MWCNT exhibited great recognition performance, higher analytical response and catalytic properties towards the TBHQ when compared to NIP-MWCNT (nanocomposite polymerized without adding TBHQ), MIP-MWCNT without hemin and MIP-hemin without MWCNT. Such results demonstrated the synergic effect of imprinting influence, MWCNT and hemin in improving the performance of electrochemical sensor. From chronoamperometric measures, the electrochemical sensor modified with MIP-MWCNT could recognize TBHQ selectively in the presence of electroactives and structurally similar compounds. Under optimized conditions by pulse differential voltammetry (pulse amplitude of 100 mV, pulse time of 25 ms and scan rate of 10 mV s −1 ) and measures in 0.15 mol L −1 H 2 SO 4 , the proposed method successfully enabled the simultaneous determination of TBHQ and butylated hydroxyanisole (BHA), yielding limits of detection of 0.85 and 0.50 μmol L −1 , respectively. The feasibility of the method was checked by simultaneous determination of TBHQ and BHA in soybean oil, margarine, mayonnaise and biodiesel, whose results were statistically equal to those achieved by high performance liquid chromatography (HPLC). [ABSTRACT FROM AUTHOR]

In this paper, a new multifunctional electrochemical platform for hydrogen peroxide (H 2 O 2 ) and nitrite (NO 2 − ) based on silver/carbon nano-composite (Ag/C NC) was firstly proposed. Ag/C NC was synthesized by using carbon dots (C-dots) as the reductant by a facile one-step synthesis method and confirmed by UV-Vis, Fourier transforms infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and dynamic light scattering. The Ag/C NC based electrodes showed excellent electrocatalytic activity toward the reduction of H 2 O 2 and the oxidation of NO 2 − . When Ag/C NC was dropped on the bare GCE, the electrocatalytic reduction of H 2 O 2 occurred and showed wide linear range from 5.00 μM to 11.05 mM with the detection limit of 0.51 μM. When Ag/C NC was dropped on graphene (GR) modified electrode, the Ag/C NC/GR/GCE showed extremely fast direct electron transfer and good electrocatalytic activity toward oxidation of nitrite. It showed wide linear range from 4.00 μM to 2.00 mM with the detection limit of 0.48 μM. The Ag/C NC/GR/GCE was successfully applied in analysis of nitrite in real samples and gained good testing recovery. Therefore, the proposed electrochemical sensors for H 2 O 2 and NO 2 − exhibited many advantages, such as operational simplicity, rapid responses, good reproducibility and stability, and can be simply tuned to utilize for electrochemical detection of H 2 O 2 and NO 2 − . This study will open a facial and simple synthesis method for preparing carbon based noble metal nanocomposite and utilizes them in detection for different purposes, which may provide new opportunity and prospect in the field of electrochemical biosensing. [ABSTRACT FROM AUTHOR]

Poor rate capability and cycling performance are the major barriers to the application of lithium rich layered oxides as the next generation cathodes for lithium-ion batteries. In this paper, a novel tactics is applied to enhance the rate property and low temperature performance of lithium rich layered oxides materials by using graphene and multi-walled carbon nanotubes as the building blocks to form a hybrid 3D conductive network in the synthesized composites. Spray pyrolysis method is employed to obtain the target material. The hybrid 3D conductive network can decrease the reaction overpotential greatly, as well as reduce the cell resistance and enhance the lithium ion transportation in the bulk material, which are confirmed by cyclic voltammetry measurement and electrochemical impedance spectroscopy. The conductivity of the obtained composite is so high that no additional conductive agent is needed in the fabrication of electrodes. Our investigation further demonstrates that the conducting framework can efficiently alleviate the polarization of pristine lithium rich layered oxides material, leading to an outstanding enhancement in rate capability, low temperature performance and cycling stability. [ABSTRACT FROM AUTHOR]

For improving the utilization and anti-poisoning performance of Pd catalysts for formate oxidation, atomic layer deposition (ALD) method was used to deposit Pd on carbon nanotubes (CNTs) and CNTs-supported Ag (Ag/CNTs). The structures of the as-prepared Pd/CNTs and Pd-on-Ag/CNTs catalysts were characterized using X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Electrochemical characterization and high-angle annular dark-field scanning TEM (HADDF-STEM) confirmed the Pd-on-Ag structure. Pd utilization, activity, and anti-poisoning performance for Pd/CNTs and Pd-on-Ag/CNTs catalysts were compared, indicating that the overall performances of the Pd-on-Ag catalysts are superior to those of Pd on CNTs without Ag. Particularly, the mass specific chronoamperometric current (I CA ) of the Pd-on-Ag/CNTs (171.8 mA mg Pd −1 ) is two times greater compared to that of Pd/CNTs (70.0 mA mg Pd −1 ). X-ray photoelectron spectroscopy (XPS) was used to explain the improved anti-poisoning performance from the aspect of electronic Pd-Ag interaction. The results in this paper demonstrated the need for rationally engineered supports for improving the anti-poisoning performance of Pd-based anode catalysts. [ABSTRACT FROM AUTHOR]

This study describes a novel flowing deposition method which can be used in situ on a fully assembled electrochemical cell to enhance the electrochemical active surface area of flow-through porous electrodes. As a test case, vanadium redox reaction rates are enhanced by flowing deposition of carbon nanotubes on carbon paper electrodes. The deposition is characterized using a recently developed analytical flow cell technique and shown to increase the electrochemical active surface area and therefore the exchange current for the limiting V 2+ /V 3+ reaction by over an order of magnitude. When applied to the anode of an assembled vanadium redox flow cell, the method nearly eliminates the overpotential associated with this reaction, thereby significantly improving the power output of the cell by up to 70% in the high voltage efficiency regime. As a surface area treatment, this flowing deposition method could be used to similarly enhance the energy conversion efficiency of many other electrochemical flow cells such as fuel cells, flow batteries and capacitive deionization cells. [ABSTRACT FROM AUTHOR]

The work reported in this paper demonstrates for the first time that graphene modified glassy carbon electrode (Gr/GC) show remarkable electrocatalysis towards Pu(IV)/Pu(III) redox reaction and the results were compared with that of single-walled carbon nanotubes modified GC (SWCNTs/GC) and glassy carbon (GC) electrodes. Graphene catalyzes the exchange of current of the Pu(IV)/Pu(III) couple by reducing both the anodic and cathodic overpotentials. The Gr/GC electrode shows higher peak currents (i p ) and smaller peak potential separation (ΔE p ) values than the SWCNTs/GC and GC electrodes. The heterogeneous electron transfer rate constants ( k s ), charge transfer coefficients (α) and the diffusion coefficients (D) involved in the electrocatalytic redox reaction were determined. Our observations show that graphene is best electrocatalytic material among both the SWCNTs and GC to study Pu(IV)/Pu(III) redox reaction. [ABSTRACT FROM AUTHOR]

Free-standing, flexible, paper-like Fe 2 O 3 /graphene/carbon nanotubes (Fe 2 O 3 /GCNTs) ternary hybrid film with a three-dimensional hierarchical structure is synthesized through a simple filtration and a subsequent reduction process. The Fe 2 O 3 particles are densely anchored onto the GCNTs conducting network, which serves as an ideal host for fast and efficient lithium storage. The layered GCNTs network not only withstands the huge stresses caused by Fe 2 O 3 expansion/extraction but prevents the agglomeration of Fe 2 O 3 upon continuous charging/discharging. The as-synthesized Fe 2 O 3 /GCNTs hybrid film is directly used as an anode for both half and full lithium-ion cells. Electrochemical measurement results indicate a high reversible capacity and a good rate capability can be realized on the hybrid when tested in half cell system. Furthermore, the prepared anode also shows favorable operation in full cell system comprising LiCoO 2 cathode. These superior electrochemical performances of the hybrid film can be ascribed to the unique micro-structure, surface properties, and the strong synergistic effects among the individual component. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional (3D) graphitic carbon nitride nanosheets-carbon nanotube (CNNS-CNT) composite was synthesized via hydrothermal reaction of 2D CNNS and 1D CNT-COOH by π-π stacking and electrostatic interactions. This CNNS-CNT composite was characterized by transmission electron microscope, scanning electron microscope, x-ray diffraction and fourier-transform infrared. In addition, the CNNS-CNT composite displayed excellent conductivity comparing with CNNS and CNT-COOH monomer. This composite was applied for electrochemical simultaneous determination of catechol (CC) and hydroquinone (HQ) with good sensitivity, wide linear range and low detection limit. In addition, this CNNS-CNT composite modified electrode was also applied to detect practical samples with satisfactory results. [ABSTRACT FROM AUTHOR]

In this paper, the novel nickel oxide@carbon (NiO@C) hollow hybrid networks (HHNs) consisted of nanotubes with interconnected branches are designed and fabricated via template-assisted electrodeposition method. Electrochemical measurements demonstrate that the NiO@C HHNs electrodes exhibit high specific capacitance ( C sp ) (572.5 F/g) at current density of 2.5 A/g, which is more than twice as that of NiO hollow networks (HNs) electrode (259.6 F/g). The NiO@C HHNs electrodes show high flexibility and excellent cycle performance (almost no capacitance loss after 2000 cycles) and exhibit superior rate capability (∼14% C sp decay with scan rate increasing from 5 to 100 mV/s). The assembled asymmetric supercapacitors (ASCs) based on NiO@C HHNs as positive electrodes and 3D active carbon (AC) as negative electrodes also shows high specific capacitance, excellent cycle performance, and high energy and power densities. Two ASC device units connected in series could drive a red light-emitting diode (LED, 2.0 V) well for more than 60 s after charging at 28 A/g for 10 s. The above results indicate that the NiO@C HHNs own promising potential for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have been widely developed for electrochemical energy conversion and storage devices for replacement of high-cost Pt-based catalysts. In this paper, a simple and convenient method is developed for improving the catalytic activity of CNTs in a controlled way. By simple heating treatment in the air, the multi-walled carbon nanotubes (MWCNTs) change with special morphologies, compositions and abundant defects (denoted as h-CNT). Those defects significantly improve the electrocatalytic performances for oxygen reduction reaction (ORR) which proceeds in a nearly four-electron pathway. The heating conditions have important effects on the structures and defect properties of h-CNTs which show a positive correlation between the defect levels and ORR performances. The small amounts of iron residues originated from nanotube growth and nitrogen doping during heating treatment also contribute to some catalytic activity. The inner walls of h-CNT remain intact during heating treatment and provide sufficient conductivity which facilitates charge transport during ORR. The h-CNT electrocatalyst shows better methanol tolerance and long-term durability than commercial Pt/C in alkaline media which makes it an alternative cathode catalyst in fuel cells. [ABSTRACT FROM AUTHOR]

• Ternary NiMoCo alloys and fluffy carbon nanotubes grown on ZIF-67-derived polyhedral carbon frameworks. • Evaporated Ni(DMG)2 provides favorable reduction atmosphere for alloy formation during pyrolysis. • The synergistic effect of NiMoCo ternary alloy and fluffy carbon nanotubes contributes to high catalytic performance. • ZIF-67DC/NiMoCo/CNT catalysts display outstanding catalytic performance for HER and OER. • The cell voltage required for water splitting was found to be ∼1.64 V at 10 mA cm−2 in alkaline medium. The synthesis of efficient and stable non-precious metal electrocatalytic materials is one of the main challenges in current overall water splitting research. Herein, this paper puts forward a facile pyrolysis synthesis strategy for the construction of ZIF-67DC/NiMoCo/CNT ternary alloy catalyst with three-dimensional nanostructure and abundant fluffy carbon nanotubes. Benefiting from the synergistic effect between NiMoCo ternary alloy and carbon nanotubes, the ZIF-67DC/NiMoCo/CNT bifunctional catalyst can yield current density of 10 mA cm−2 at overpotentials of 85 mV and 306 mV over HER and OER in alkaline medium, respectively. The overall water splitting device can deliver current densities of 10 mA cm−2 for long periods of time at drive voltages as low as 1.64 V with nearly negligible decay in potential. This study provides a novel and operable method for the design of non-precious metal electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

Here in-situ Raman indicates that the shuttle effect induced by polysulfides occurs during the whole discharge and charge process in lithium-sulfur batteries (LSBs), leading to irreversible loss of sulfur and generation of lithium dendrites. To solve the above problems, we construct a N-doped carbon nanotubes/carbonized cellulose paper (IF-N-CNTs-CCP) with three-dimensional conductive network structure through noncovalent modification assisted high-temperature carbonization. IF-N-CNTs-CCP interlayer can effectively block the shuttle effect by strong chemisorption and physical barrier, improving the utilization of sulfur. However, it doesn't prevent the free migration of lithium ions, resulting in a remarkable acceleration of electrochemical reaction kinetics. Moreover, the three-dimensional IF-N-CNTs-CCP interlayer can provide a large number of lithiophilic sites and significantly reduce the regional current density, thus inhibiting the growth of lithium dendrites, enhancing the safety of LSBs. As a result, the LSBs with IF-N-CNTs-CCP interlayer deliver a negligible capacity fading rate of 0.037% per cycle after 500 cycles at 2.0 C, and a high-capacity retention of 95% at 0.2 C with a sulfur loading of 3 mg/cm2 with a correspondingly lean electrolyte condition (E/S ratio = 6 µL/mg). This work provides an effective strategy for the application of functional interlayer in LSBs, which can suppress the shuttle effect and lithium dendrite. [Display omitted] [ABSTRACT FROM AUTHOR]

• Macadamia nut shells are agricultural waste, which is economical and environmentally friendly as a carbon source. • The structure of macadamia nut shell is compact, and the porous carbon material prepared with it has stable properties. • The porous carbon material prepared from macadamia nut shells has a developed pore structure, ultra-high specific surface area and large pore volume, which can effectively increase the sulfur loading, adsorb polysulfide and limit the "shuttle effect". • The composite material prepared by combining porous carbon material and CNTs has the dual advantages of them. The three-dimensional conductive network structure of the composite material can effectively adsorb polysulfide and promote the conduction of electrons, so that the electrochemical performance has been greatly improved. Biomass carbon material as the sulfur storage matrix of lithium–sulfur batteries is one of the research hotspots. In this paper, the macadamia nut shells are used as the precursor to prepare porous carbon material. By exploring the effect of temperature on the microstructure and electrochemical performance of porous carbon materials during activation, it is found that the porous carbon material prepared under the activation condition of 900 °C has a developed pore structure, super high specific surface area (3552.7 m2•g−1), larger pore volume (2.2 cm3•g−1) and higher mesoporous content (23.85%). And the composite cathode material with the sulfur content of 70.1% has the highest specific capacity, and the initial discharge specific capacity for 0.2 C can reach 942.4 mAh•g−1. The composite material S/OCNT@OPC-1:1 obtained by compounding it with carbon nanotubes at a mass ratio of 1:1 has higher specific capacity, better rate performance and cycle performance. At 0.2 C, the initial discharge specific capacity is as high as 1252.6 mAh•g−1, and it remains at the level of 717.3 mAh•g−1 after 200 cycles. Even at 1 C, the specific capacity is still 984.3 mAh•g−1, and it remains at 690.9 mAh•g−1 after 200 cycles, and the capacity retention rate is 70.2%. Our work shows that the composite material obtained by combining low-cost biomass carbon materials and carbon nanotubes as the cathode material for lithium-sulfur batteries has obvious advantages. [ABSTRACT FROM AUTHOR]

A facile one-step wet chemical method for preparing SnO 2 @OCNTs composite was described in this paper. The formation of composite is dried by the capillary force and electrostatic interaction. The results reveal that the Open-tips CNTs (OCNTs) are filled with ultrafine SnO 2 nanoparticles (4–6 nm) and with a few SnO 2 nanoparticles on the outside surface. The composite delivers a capacity of 848 mAh g −1 (based on the mass of composite) in the first cycle and keeps 83.5% of the original capacity after 300 cycles at the current density of 70 mA g −1 . Furthermore, the composite still releases a capacity of 398 mAh g −1 at the current density of 3000 mA g −1 . [ABSTRACT FROM AUTHOR]

• Single-phase polythiophene-MWCNT composite achieved through in-situ chemical oxidative synthetic procedure. • PTh/MWCNT application as cathode for rechargeable Mg battery demonstrates improved electrochemical activity over pristine PTh. • A high discharge capacity of ∼157 mAh.g−1 achieved at an applied current density of 60 mA.g−1, sustained for >100 cycles. • Post electrochemical analysis defines the multi-polaron state associated with polythiophene composite electrode. • Electrochemically induced rearrangement/reorganization in electrode morphology imparts improved stability. This paper showcases polythiophene/multi-walled carbon nanotube (PTh/MWCNT), synthesized via chemical in-situ oxidative method as an active cathode material for rechargeable magnesium (Mg) battery. Successful formation of the composite material is confirmed by Fourier transform-Infra Red and X-ray diffraction analysis. Morphological evaluations of the cathode materials employing field emission scanning- and transmission- electron microscopy (FESEM and TEM) reveal the composites' one-dimensional, homogeneous phase formation. The feasibility of PTh/MWCNT composite as a prospective positive electrode for rechargeable magnesium battery is assessed using cyclic voltammetry and galvanostatic charge-discharge. Comprehensive electrochemical studies demonstrate a significantly enhanced performance of the optimized PTh/MWCNT cathode composition. A considerably high specific capacity of ∼157 mAh.g−1 coupled with appreciable coulombic efficiency (∼70%) and excellent reversibility (>100 cycles), at high current density, indicates great promise. Analysis by X-ray photoelectron spectroscopy confirms the existence of multi-polaron state of the polymer/composites providing crucial clues towards proposing a plausible mechanism of charge transport and storage. Affirmation of improved stability and electrochemically induced rearrangement in electrode morphology is clearly evidenced from the FESEM studies post charge-discharge cycles. These encouraging findings suggest PTh/MWCNT composite electrodes possess the desirable physical and electrochemical properties, to be considered as a potential polymer electrode for rechargeable Mg-battery. Schematic representation of red-ox reactions occurring in the Mg-PTh/MWCNT cell consisting 1.0M Mg(ClO 4) 2 /acetonitrile electrolyte and representative cyclic voltammetry of the cell over multiple number of cycles [Display omitted]. [ABSTRACT FROM AUTHOR]

• A novel porous cage-like structure TMOs with 3D network for LIB anode and capacitors. • The zinc and nickel doping MnCo2O4 expand the transport channels of Li+ ions. • Strong electronic interaction in the double heterointerface optimize electronic environment for electron transport. • The material delivers extra pseudocapacitive and enhanced diffusion rate of Li+ ions for excellent electrochemical performance. The rapid development of bimetallic-based materials (BTMs) in lithium ion battery (LIB) is mainly attributed to its synergistic effect and multi-component flexibility, but it still has huge challenge due to the unstable cycling performance, poor conductivity and understanding of additional capacity. In this paper, zinc atom-doped NiO-MnCo 2 O 4 matrix (NZ-MC) with double heterostructure is prepared, and then the dispersed carbon nanotube (CNT) is compounded to construct 3D conductive network hybrid (NZ-MC@CNT), which can be served as excellent anode electrode for energy storage. Optimized NZ-MC@CNT has reversible discharge of 862.1 mA h g −1 at the higher current density 5 A g −1 after 2000 cycles and the superior rate capability of 818.2 mA h g −1 at 12 A g −1. Based on the detailed phase transition analysis and kinetic analysis, the high-energy application of optimized NZ-MC@CNT is mainly attributed to the outstanding pseudocapacitance at the region of double heterogeneous interface, thereby accelerating the reaction kinetics process. Mainwhile, the theoretical calculation and kinetics analysis are performed to deeply reveal the (de)lithiation pathways related to the energy storage mechanism about excellent electrochemical performance. In addition, NZ-MC@CNT was saved for different energy storage systems (LIBs/LICs/Li-DIBs) and present excellent performance, which further demonstrates the application potentiality of NZ-MC@CNT. Novel porous cage-like structure ZnNi-MnCo2O4@CNT with 3D conductive network and double heterostructures for Li+ half cell and capacitors (LIBs/LICs/Li-DIBs). [Display omitted] [ABSTRACT FROM AUTHOR]

Currently, it is still a big challenge to develop highly active and robust trifunctional non-noble electrocatalysts to meet the practical application of renewable energy storage and conversion devices including metal-air batteries and water electrolyzers. N and O co-doped helical carbon nanotubes encapsulated with CoFe alloy (CoFe@NO CNT) were prepared in situ on carbon paper using ZIF67 as precursor through ion exchange and chemical vapor deposition (CVD) pyrolysis methods. Comparative studies found that the heterogeneous catalysis of CoFe alloy produced spiral carbon nanotubes, which had a much higher N and O doping content than conventional carbon nanotubes containing monometallic cobalt particles. On the basis of the advantages of in situ growth and 3D open structure of catalytic electrode, the helical carbon nanotubes with abundant N catalytic species, C = O functional groups and core-shell structure exhibit superior electrocatalytic activity for ORR/OER/HER. The zinc-air battery (ZAB) and water electrolysis device based on CoFe@NO CNT electrodes showed peak power density (142 mW/cm2), specific capacity (819 mAh/g Zn), low overall water splitting voltage (1.57 v @ 10 mA/cm2) and good stability. Two CoFe@NO CNT based ZABs in serial connection can efficiently drive the electrolyzer with two same CoFe@NO CNT/CFP electrodes to split water and two quasi-solid state ZABs in series provide a peak power of 212 mW to light a red light-emitting diode (LED) indicator. [ABSTRACT FROM AUTHOR]

• A unique hierarchical structure of Ni Co LDH composites linked by CNTs was prepared. • CNTs/Ni Co LDH composites exhibited excellent electrochemical performance. • CNTs act like plant conduction tissues to transport electrons and ions into the interior of material and effectively enhance its stability. • The hybrid supercapacitor possessed high energy density and superior cycling stability. The instability and poor conductivity of metal-organic frameworks (MOFs) are the main factors limiting its application in supercapacitors. In this paper, inspired by the bionic concept of plant conduction tissue, a unique hierarchical structure with Ni Co layered double hydroxide linked by carbon nanotubes (CNTs/Ni Co LDH) was designed and synthesized for the first time. Among them, the introduction of CNTs can not only transport electrons and ions into the interior of materials, but also can play a role in the connection when the materials break, just like lotus root silk. Furthermore, the phase transition from MOF to LDH can enhance the redox activity of the materials and thus improve the coulomb efficiency. When used as an electrode material, CNTs/Ni Co LDH composites had a superior specific capacitance of 1628 F g−1 at 1 A g−1, and had an enhanced rate capability. The assembled hybrid supercapacitor exhibited a competitive energy density of 38.89 Wh kg−1 at power density of 800 W kg−1, and had a remarkable cyclic stability with a specific capacitance retention of 99.379% for 10,000 cycles at 5 A g−1. This bionic concept of plant conducting tissues can provide a new way to optimize the electrochemical performance of pure MOFs or metal hydroxide materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2) is one of the promising candidates for hydrogen evolution reaction (HER), it's HER properties can be extremely enhanced by the construction of nanostructure and the regulation of electronic structure. In this paper, hierarchical composites with MoS 2 and carbon nanotubes (CNTs) as the noble metal-free electrocatalysts for HER were fabricated through calcination and hydrothermal processes, in which the MoS 2 nanosheets with Ni atoms incorporation were vertically grown on the outsides of nitrogen (N)-doped CNTs. The constructed hierarchical structures provide large specific surface area of about 150 m2 g−1 and high structure stability. Importantly, the MoS 2 nanosheets with enlarged interlayer spacing possess ultrathin structure of about 4 nm in thickness. Owing to the incorporation of Ni atoms, abundant unsaturated S atoms are obtained in the basal plane, which leading to more active sites exposed during HER processes. Meanwhile, N-doped CNTs can act as the substrate for MoS 2 nanosheets growing and simultaneously improve the conductivity of catalyst. Based on the synergy of hierarchical structure, increased active sites and enhanced conductivity, the as-prepared electrocatalysts exhibit superior HER activity with low overpotentials, small Tafel slopes and long-time durability in both acidic and alkaline electrolytes. The overpotentials of 158 and 179 mV were required to drive HER current density up to 10 mA cm−2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. This work reports a highly efficient MoS 2 -based electrocatalyst for HER via fabricating hierarchical structure and doping Ni atoms. Image 1 [ABSTRACT FROM AUTHOR]