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Abstract A facile one-step solid-phase synthesis strategy is developed for synthesizing a binder-free molybdenum disulfide/carbon fibers paper (MoS 2 /CFP) anode. The microstructure, composition, morphology and electrochemical performances were investigated. It is found that the thin MoS 2 layers are well anchored on the interlaced carbon fibers to form MoS 2 /CFP, which has mesoporous structure and large specific surface area of ∼18.8 m2g-1. As a result, the obtained MoS 2 /CFP anode exhibits a reversible capacity of 261 mAh·g−1 with 31.2% loading ratio of MoS 2. After subtracting the capacity of CFP, the MoS 2 in the composite anode delivers a reversible capacity of 539 mAh·g−1 and shows better cycle stability than commercial MoS 2 after 100 cycles at 100 mA g−1. The remarkable electrochemical performances could be attributed to the buffer space among carbon fibers for the volume changes of MoS 2 as well as the highly conductive carbon fibers network, suggesting that the MoS 2 /CFP is a promising binder-free anode for lithium-ion batteries. Graphical abstract Image 1 Highlights • A one-step solid-phase synthesis strategy is developed to fabricate MoS 2 /CFP anode. • The MoS 2 and the carbon matrix of MoS 2 /CFP composite were synthesized synchronously. • The MoS 2 /CFP anode exhibits enhanced cycling performance and high-rate capability. • The mechanism of the enhanced electrochemical properties was discussed for MoS 2 /CFP. [ABSTRACT FROM AUTHOR]

Use of aluminum alloy anodes as metal fuel in electrochemical batteries has specific advantages in numerous applications. In this paper, we report novel Al alloy anodes obtained by adding In and Bi to a reported Al ternary-element alloy, Al-Zn-Sn. An electron probe microanalyzer is used to obtain the elemental composition of Al-5Zn-0.1Sn, Al-5Z-0.1Sn-0.1In, and Al-5Zn-0.1Sn-0.1In-0.1Bi. Tafel analysis, electrochemical impedance spectroscopy, and constant-current chronopotentiometry are performed for electrochemical analysis. In addition, the self-corrosion of the alloys is examined to determine the hydrogen evolution and anode discharge stability. These results indicate that Al-5Zn-0.1Sn-0.1In-0.1Bi has the highest anode performance. On the basis of the scanning electron microscopy and transmission electron microscopy microstructure analysis, we propose that the dissolution and sedimentation process induced by Bi nanoprecipitates may activate a passive Al surface, significantly enhancing the discharge efficiency. • Al-5Zn-0.1Sn-0.1In-0.1Bi alloy is first synthesized which displays high discharging performance in battery applications. • XRD, SEM, and TEM showed the minor crystals and grains in Al-5Zn-0.1Sn-0.1In-0.1Bi. • The self-corrosion is examined indicating a dissolution mechanism of the Al alloy. • In and Bi in the Al alloy collapsed during discharge, which refreshed the passivated Al surface. [ABSTRACT FROM AUTHOR]

Abstract The poor incorporation between graphene sheets and Ag NPs has become a problem in the application of graphene based composites. In this paper, graphene oxide (GO) was functionalized with triethylene tetramine (TETA), and then reduced graphene oxide/Ag nanoparticles composites (RGO/Ag NPs) were prepared using TETA as the reductant via a hydrothermal method. TEM, SEM, XRD, FTIR, EDS and Raman spectra were used to investigate the morphologies and structures of as-prepared RGO/Ag NPs composites. The results showed that Ag NPs were successfully incorporated with RGO sheets and the completely separated RGO sheets were disordered. Compared with functionalized GO (FGO), the intensity ratio of D band to G band (I D / I G) for RGO/Ag NPs composites decreased, and I D / I G of F6G was 1.08. When the content of AgNO 3 solution increased, the Ag content in the composite also increased and that in F8G was 26.23 wt%. However, the size of Ag NPs in F8G remained small and that was in the range of 10–20 nm. Besides the good electrochemical performance according to the CV curves, the detection limit of the trace concentration of Cu2+, Cd2+ and Hg2+ for F8G was calculated to 10−15 M, 10−21 M and 10−29 M, respectively. Although the detection limit for Cd2+ and Hg2+ had certain derivation, as-prepared RGO/Ag NPs composites can be used as the candidate of the sensors for detecting the trace of these heavy metal ions. Graphical abstract Image 1 Highlights • RGO/Ag NPs composites were prepared using TETA as the reductant. • Ag NPs were successfully incorporated with RGO sheets. • The size of Ag NPs was in the range of 10–20 nm. • RGO/Ag NPs were very sensitive to detective Cu2+, Cd2+ and Hg2+. [ABSTRACT FROM AUTHOR]

Abstract Due to cage-like voids in the lattice, skutterudite NiP 3 is regarded as a promising negative electrode material with high specific capacity. The fabrication of phosphide based on ceramic routes always leads to multiphase formation and serious agglomeration of particles. The resultant cycle performance is thus to be improved. In this paper, single phase skutterudite NiP 3 particles (NNP) were fabricated by the reaction of NiS precursor with red phosphorus. As comparison, skutterudite NiP 3 was also prepared by the direct reaction of Ni with red phosphorus (MNP). After 50 cycles, NNP retained 712 mAh g−1 at current density of 159.1 mAg−1, while MNP delivered a capacity less than that of commercial graphite within 16 cycles. According to CV analysis, the improvement in cycling performance of NNP was attributed to an insertion-dominated two-step lithiation process, while MNP undergone a straightforward conversion process. The formation of layer-structured intermediate Li x NiP 3 phase by an insertion reaction would compete with the direct generation of Li 3 P and Ni (0) composites by a typical conversion reaction. The improvement in the rating performance originates from the low-impedance of charge transfer and fast migration of Li+ in the electrode of NNP. Graphical abstract Image 1 Highlights • Single phase skutterudite NiP 3 is fabricated using NiS precursor. • A size dependent lithiation path selection is confirmed. • An insertion-dominated lithiation process improves cycling performance. • The selection of lithiation process depends on the thermodynamic and kinetic competition. [ABSTRACT FROM AUTHOR]

Abstract This paper reported the comparison of electrochemical properties of carbon nanofibers (CNFs), interconnected carbon nanofibers (ICNFs), and carbon-manganese oxide composite nanofibers (C/MnO x) fabricated by a conventional and a core-shell electrospinning technique, respectively, with the combination of heat treatment and CO 2 - activation. Concerning material characterizations, the field emission scanning electron microscopy (FE-SEM) revealed the fiber-fiber interconnection patterns, the manganese oxide nanoparticles, and other fiber morphologies. Moreover, the FE-SEM results also exhibited the fiber diameters and particle sizes, which were consistent with the specific areas obtained from the N 2 -adsorption/desorption techniques. The electrochemical performances were measured in aqueous electrolyte by three-electrode system. In addition, X-ray diffraction techniques (XRD) showed the phases of amorphous carbon, graphite structure, and manganese oxides, while the Raman analysis determined the carbon qualities in the samples. Furthermore, the differentiate-canning calorimetry (DSC) and the thermogravimetric analysis (TGA) displayed the thermal properties of all samples. As results, the C/MnO x exhibited the greatest specific capacitance of 213.7 F g−1 at the current density of 0.5 A g−1 with the energy density of 30 mWh g−1 at the power density of 249 mW g−1 and the great cycling stability of 97% after 1000 cycles. Highlights • The samples were characterized by TGA, FE-SEM, XRD, Raman, and BET. • The core-shell electrospinning can produce fiber-fiber interconnected CNFs. • C/MnO x composite nanofibers exhibited excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Spinel Co 3 O 4 , as conversion-type transitional metal oxide, has attracted extensive interest for LIBs anode due to its high theoretical capacity. The application of transitional metal oxide including Co 3 O 4 anode has been proved challenging due to voltage hysteresis, bad rate capability, extremely low initial Coulombic efficiency (typically 65∼70%), and volume change induced mechanical failure. Among the facing problems, the fundamental understanding of severe capacity fading at high C-rate is clearly needed to be unveiled. In this paper, we utilized in situ transmission electron microscopy (TEM) to study the electrochemical reaction process of spinel Co 3 O 4 anode and firstly unveiled the rate-dependent morphological and structural evolution process. It has been demonstrated that the structural evolution from pristine Co 3 O 4 phase to the formation of Co/Li 2 O composites during lithiation (bias = −3 V). Impressively, the Co/Li 2 O composites could fully delithiated into pure tightly-contacted CoO crystals (∼1.45 nm) at lower delithiated bias (+3 V); while the lithiated products partially transformed into the CoO crystals, and further suffered a severe aggregation (∼6 nm) at higher delithiated bias (+8 V). These findings advance the understanding of the mechanism of capacity fading at high current density (C-rate) in conversion-type spinel Co 3 O 4 anode for lithium ion batteries. [ABSTRACT FROM AUTHOR]

• B2 phases in Al 0.3 CoCrFeNi HEAs are purposely controlled by annealing treatment. • Effect of B2 phases on corrosion resistance of Al 0.3 CoCrFeNi HEAs is studied. • The B2 phases deteriorate the pitting corrosion resistance of Al 0.3 CoCrFeNi HEAs. • B2 phases act as preferential pit nucleation sites and facilitate pit propagation. The corrosion resistance of Al-Co-Cr-Fe-Ni high entropy alloys (HEAs) is probably affected by B2 phases. In this paper, the effect of B2 phases on the corrosion behavior of Al 0.3 CoCrFeNi HEAs in 3.5 wt% NaCl solution is clarified in this paper by purposely controlling the formation of B2 phases using annealing treatment. The microstructure characterization reveals that the content of (Al, Ni)-rich and Cr-poor B2 phases increases and the electrochemical measurements show that the pitting corrosion resistance is deteriorated as the annealing temperature decreases. Accordingly, the B2 phase is confirmed to be detrimental to the corrosion resistance of Al 0.3 CoCrFeNi HEAs. It can be attributed to the preferential dissolution of B2 phases causing easier pit initiation, which is evidenced by the corrosion morphology observation and scanning Kelvin probe force microscopy measurements, and to the slower repassivation rate leading to easier pit propagation, as demonstrated by the quantitative analysis of potentiostatic polarization curves. [ABSTRACT FROM AUTHOR]

This paper reports the RuO 2 -SnO 2 binary film synthesis and the influence of the SnO 2 composition increase in the ion transport and pseudocapacitive properties of RuO 2 . The binary oxide was synthesized by polymeric precursors method followed deposition on a titanium substrate. XRD analysis showed the phases formed and the crystallites size of the samples. SEM allowed studying the morphology variation of the films with the addition of SnO 2 . The material obtained was evaluated by electrochemical techniques in 1 M H 2 SO 4 electrolyte solution. The voltammograms showed that the pseudocapacitive characteristic of the RuO 2 – SnO 2 binary film remained even for greater amount of SnO 2 in the binary mixture. The electrochemical impedance spectroscopy results are discussed in terms of complex capacitance and complex power. The relaxation time constant of the systems and capacitance values at low frequency, were determinate from complex capacitance plots. [ABSTRACT FROM AUTHOR]

Oxidation film growth is an inextricable part of the nucleation mechanism at the initial stage of oxidation on the lead anode surface, which results from different degrees of corrosion resistance. In this paper, Pb, Pb-Sn-Ag, Pb-Ca, and Pb-Ca-Sr alloys were taken as raw materials to study the element doping effect on the nucleation growth mode of the oxide film on the lead alloy surface using CrO 3 solution as an electrolyte. The results show that four kinds of alloy anodes behave in accordance with the Bewick 2D nucleation growth method during the oxidation process, while there are differences among anodes. Nucleation is remarkably related to the internal stress and structure of the lead alloy substrate; internal stress significantly influences the electrochemical properties of oxidation film. The oxidation film generated on the Pb-Sn-Ag alloy anodes is found to have a better corrosion resistance than those on the other anodes by means of electrochemical testing, as the lead anode features small internal stress and nucleates in a gentle manner, its thickness is the smallest as well. [ABSTRACT FROM AUTHOR]

Rechargeable Li-O 2 batteries have great potential on achieving large-capacity electrochemical energy storage. However, the poor cyclic stability seriously limits its commercial application. In this paper, peanut shaped MnCo 2 O 4 which winding by multi-walled carbon nanotubes (MCO/MWCNTs) were synthesized through a facile solvothermal method. As-prepared MCO/MWCNTs have a unique hierarchical mesoporous of three-level pore sizes and show good ORR and OER electrocatalytic activity. When MCO/MWCNTs served as cathode catalysts in Li-O 2 batteries, the batteries exhibited long cycle life of 120 times at 100 mA g −1 with a limited capacity of 500 mAh g −1 and high discharge capacity up to 8849 mAh g −1 with a restrict voltage of 2 V at 100 mA g −1 . [ABSTRACT FROM AUTHOR]

In this paper we report the comparative supercapacitive performance of the electrodeposited MnO 2 films prepared using different plating solutions, namely KMnO 4 , MnSO 4 and Mn(CH 3 COO) 2 . All the MnO 2 films possess the hexagonal phase of epsilon manganese dioxide ( ε -MnO 2 , akhtenkite), consistent with the JCPDS card no. 12-0141. The analyses of SEM images reveal that the electrodeposited MnO 2 film prepared from the plating solution KMnO 4 has a porous microstructure comprising of sparsely distributed grains, whereas that prepared from MnSO 4 has a uniform morphology covered with nanofibers having porous spaces between them, and that prepared using Mn(CH 3 COO) 2 exhibits a dense morphology comprising of nanofibres. The galvanostatic charge/discharge measurements show the maximum specific capacitance 325.6 F/g for the MnO 2 film prepared using KMnO 4 , followed by 275.2 F/g and 174.5 F/g for the films prepared by MnSO 4 and Mn(CH 3 COO) 2 ., respectively. The variation in specific capacitances of the films is attributed to varying morphological features of the films. [ABSTRACT FROM AUTHOR]

In this paper, the effects of Ta substitution for Nb, on the microstructure and corrosion fatigue behavior of metastable Ti-18Nb-14Zr biomedical alloy are investigated for the first time. For this purpose, besides previously studied ternary Ti-18Zr-14Nb alloy, new quaternary Ti-18Zr-13Nb-1Ta (at.%) biomedical alloy was also synthesized by vacuum arc remelting method and subjected to thermomechanical treatment processes. The in situ electrochemical behavior and subsequent functional fatigue life of both alloys showed a strong dependence on the composition and microstructure. The electrochemical results from the test bench demonstrated that during monotonic cycling the fatigue life of Ta-added alloy was significantly longer than that of the Ti-18Zr-14Nb alloy. Thus, the addition of Ta to the ternary Ti-18Zr-14Nb alloy was found to be very effective in increasing the resistance to fatigue degradation mainly by exhibiting excellent protective passivation tendency. Based on the electrochemical evaluation and fractrographic characteristics, it is concluded that the combined effect of the stable passive film formation and higher development of a nanosubgrained structure in β phase results in the prolonged fatigue life of Ta-added alloy. [ABSTRACT FROM AUTHOR]

Synthesis of Ti/TiN hard coatings on different substrates has been the subject of several researchers in the last decades; however, a more compressive perspective is required for the investigation of the influence of deposition parameters depending on the substrate. This paper focus on evaluating tribological and electrochemical properties of Ti/TiN bilayered coatings deposited by r.f. magnetron sputtering on AISI 316L stainless steel substrates in 3.5 wt% NaCl solutions. Numerous factors can influence the electrochemical performance and tribological properties of the coatings; for this reason, the surface modifications through thickness, texturing and morphology were realized varying the sputtering parameters (substrate temperature, T, Power, P, target-to-substrate distance t-s, and Ar/N 2 gas ratio). Ti/TiN films were composed of Ti, N, which are correlated with to Ti-N, Ti-O-N and O-Ti-O phases. The friction coefficient varies from 0.12 to 1.3 by the influence of the deposition parameters; the adhesion strength shows a cohesive failure indicating that in all samples coating adhesion to steel was high enough. The corrosion resistance of Ti/TiN bilayered coatings was correlated to both the Ti/TiN film densification and formation of O-Ti-O compounds. [ABSTRACT FROM AUTHOR]

The LiV 1-x Co x PO 4 F/C (x = 0, 0.01, 0.03 and 0.05) composite cathode material for lithium ion batteries has been successfully prepared through the modified solid state method assisted by sonication and mechanical activation. Here, the influence of cobalt doping on the physical and electrochemical performances are investigated. In this paper, we adopted the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM)/energy dispersive spectrometer (EDS), cycle voltammetry (CV), electrochemical impedance spectrum (EIS) and charge-discharge test to investigate the influence of cobalt doping on the different aspects of the materials, including the physical and electrochemical properties. Compared with the original simple, the cycle and rate performance of cobalt doped samples has increased to some extent. We found that the LiV 0.97 Co 0.03 PO 4 F/C sample showed the best electrochemical performance. The lithium ions diffusion constant (D Li+ ) of the LiV 0.97 Co 0.03 PO 4 F/C (1.86321 × 10 −13 cm 2 s −1 ) is much higher than that of LiVPO 4 F/C (2.06453 × 10 −14 cm 2 s −1 ). [ABSTRACT FROM AUTHOR]

Chemical oxidation synthesis of graphene oxide (GO) through modified Hummers methods has been widely employed for producing graphene- or reduced GO (rGO)-based advanced functional materials such as rGO/MnO x nanocomposites. However, the manganese species in GO colloids are usually washed out during GO synthesis through modified Hummers methods, causing manganese waste and environmental risk. In this paper, we report preparation of rGO/MnO x nanocomposites, in which MnO x is composed of Mn 2 O 3 , Mn 3 O 4 , and MnO 2 components, through anneal treatment of the precursor counterparts obtained by simple pH tuning of GO colloids. The rGO/MnO x nanocomposites exhibit superior electrochemical performance for supercapacitors. rGO/MnO x -5, derived from GO colloids with pH 5, exhibits a high gravimetric discharge capacitance ( C dis ) of 191 F g −1 at 20 A g −1 and a high capacitance retention (82.9%) relative to C dis at 1 A g −1 . Furthermore, typical symmetric supercapacitor cells made from rGO/MnO x -5 show a high areal capacitance (172 mF cm −2 ) and excellent capacitance retention (96.6%) at 2 A g −1 (10 mA cm −2 ) for 20,000 cycles, holding great potential for practical applications. The superior electrochemical performance of rGO/MnO x nanocomposites is attributed to multiple charge storage mechanisms in association with the coexistence of mixed-valent manganese oxides. [ABSTRACT FROM AUTHOR]

A facile and novel method of growing nickel hydroxide nanoparticles on polypyrrole nanotubes (Ni(OH) 2 /PNTs) is presented using methyl orange and ferric chloride formed fibrillar complex as self-degrading tubular template coupled with hydrothermal synthesis. The Ni(OH) 2 /PNTs samples were characterized by SEM, TEM, FTIR, XRD and XPS. As pseudocapacitors, the obtained Ni(OH) 2 /PNTs in three-electrode configuration display a significantly enhanced specific capacitance (864 F/g at 1 A/g), better rate performance, lower charge-transfer resistance and higher cycling performance (91.1% of the initial capacitance retention at 5 A/g over 2000 cycles) compared to the individual Ni(OH) 2 and PNTs, and previously reported composite electrodes based on Ni(OH) 2 or PNTs. Besides, the symmetric supercapacitors of Ni(OH) 2 /PNTs in two-electrode configuration show a maximum energy density of 18.8 Wh/Kg at the power density of 414.6 W/Kg and a maximum power density of 3.4 kW/kg at the energy density of 8.4 Wh/Kg. The high electrochemical performance of Ni(OH) 2 /PNTs can be attributed to the synergistic effect of both components and the unique nanostructure. These encouraging results reveal that the Ni(OH) 2 /PNTs can be used as promising electrode materials for supercapacitors in energy storage. In addition, the method described in this paper provides a generalized route for the construction of transition metal oxides (hydroxides)/PNTs-based composite nanostructures with improved electrochemical performance. [ABSTRACT FROM AUTHOR]

In this paper, a transparent all-solid-state battery was manufactured by RF magnetron sputter, for the first time. LiFePO 4 and Li 4 Ti 5 O 12 are popular cathode and anode materials, respectively. For the solid-state electrolyte coating, the Li 3 PO 4 material is also promising solid electrolyte materials due to the high ionic conductivity. The stack structure of the battery was silver paste/anode ( Li 4 Ti 5 O 12 ) /electrolyte ( Li 3 PO 4 ) /cathode ( LiFePO 4 ) /ITO/glass . An indium tin oxide (ITO) coated glass substrate was used as a transparent and conductive material. The resistance of the coated ITO layer is 40 Ω. RF power for the LiFePO 4, Li 3 PO 4, and Li 4 Ti 5 O 12 layers deposition process was adjusted to 100 Watt at argon atmosphere. This stack structure didn't contain any liquid or gel electrolyte layer. The fully solid electrolyte was deposited by the RF magnetron sputter. The mean crystallite sizes of the deposited layers approximately 30 nm, 21 nm and 30 nm for LiFePO 4 , Li 3 PO 4 and Li 4 Ti 5 O 12 layer, respectively. The transparency of the manufactured battery is approximately 80%. Electrochemical impedance analyses and cyclic voltammetry measurements were done. The Nyquist diagram and equivalent circuit model were determined. Warburg constant and Li-ion diffusion coefficient were calculated approximately 38 Ω/s −1/2 and 4.2 × 10 −10 cm 2 /s, respectively. The capacity of the transparent all-solid-state battery was measured as to be 600 μAh/g. The value of the According to obtained results, deposited battery is a quasi-reversible system because of the differences between cathodic and anodic peak potential is calculated about 52 mV. Warburg, Li-ion diffusion coefficient and capacity of the deposited battery show very good adherence with literature. [ABSTRACT FROM AUTHOR]

As one of the most efficient, low-cost, and readily available electrocatalysts for oxygen evolution reaction (OER) in alkaline environments, the nickel-iron electrocatalyst is of great significance to commercial water splitting. In this study, NiFe-layered double hydroxide loaded on nickel foam (NiFe-LDH/NF) was synthesized via a simple one-step hydrothermal method, whose OER catalytic performance could be successfully optimized by further electrochemical reconstruction. The results show that NF is an effective precursor to loading crystallized Ni(OH) 2 nanoparticles during hydrothermal synthesis, leading to the generation of high-performance NiOOH during OER reconstruction. Under the optimal Ni:Fe feeding ratio, Ni 2 Fe 1 -LDH/NF requires an ultra-low OER overpotential of 239 mV at 50 mA cm−2 and 260 mV at 100 mA cm−2, whose Tafel slope is only 64.1 mV dec−1. Impressively, Ni 2 Fe 1 -LDH/NF also achieves an ultra-low voltage of 1.44 V at 10 mA cm−2 with excellent long-term stability for overall water splitting. Unlike the previous viewpoint that only Ni species dominate surface reconstruction of NiFe-LDH, in this article the decisive influence related to Fe species on the reconstruction layers' activity and stability is confirmed by electrochemistry, Raman, and XPS analysis during reconstruction process. During OER reconstruction, the surface Ni:Fe ratios can be "self-adaptively" regulated to an appropriate region, thus the stable reconstruction layers rich in NiOOH can be formed as the protective shells for NiFe-LDH. Furthermore, such "self-adaptive" reconstruction, assisted with appropriate initial Ni:Fe feeding ratios, can also stimulate more Ni3+ active sites for OER, benefitting the outstanding catalytic performance of NiFe-LDH/NF for overall water splitting and prospective large-scale application. [Display omitted] • There are some highlights in this paper may be found interested by the general readers. • Unstable iron-rich phases start self-adaptively electrochemical reconstruction. • Self-adaptive reconstruction promotes the OER catalytic activity and stability. • The optimal electrocatalyst exhibits 260 mV overpotential at 100 mA·cm−2 for OER. • The electrocatalyst only needs 1.44 V at 10 mA·cm−2 for overall water splitting. [ABSTRACT FROM AUTHOR]

This paper is focused on the synergistic effect of Fe site multi-doping, which is a promising target to adequately enhance the electrochemical performance of LiFePO 4 by means of cation doping method. Ca, Mn and Zn are selected as the doping elements, and the doping amounts are designed as inequality and equality multi-doping. The effects on structure micro-variation are evaluated in terms of cell parameters and Li O bond length according to the Rietveld refinement results. The effect tendency on structure micro-variation is approximately corresponding with the electrochemical performance, which can be concluded mainly as (i) in the case of inequality amount doping, Zn predominant doping exhibits more beneficial effect than Mn predominant doping, while Ca predominant doping is beneficial for cycling performance but harmful for rate capability; (ii) in the case of equality amount doping, appropriate doping amount (LiFe 0.94 Zn 0.02 Mn 0.02 Ca 0.02 PO 4 ) exhibits both merits of Zn predominant doping for rate capability and Ca predominant doping for cycling performance, while high doping amount (LiFe 0.88 Zn 0.04 Mn 0.04 Ca 0.04 PO 4 ) just exhibits merit of Ca predominant doping; (iii) among these multi-doping samples, LiFe 0.95 Zn 0.03 Mn 0.01 Ca 0.01 PO 4 and LiFe 0.94 Zn 0.02 Mn 0.02 Ca 0.02 PO 4 exhibit better electrochemical performance. This study of synergistic effect has reference significance for the development of cation doping method of modifying LiFePO 4 . [ABSTRACT FROM AUTHOR]

In this paper, a framework of macro-/micro-porous carbon derived from commercial lignin is prepared by one-step carbonization/activation method and then utilized as sulfur-loading matrix to assay the effect of sulfur-loading time on the structural and electrochemical properties of carbon-sulfur composite (C-S-t, t defined as sulfur-loading time). As-prepared porous carbon possesses a high specific surface area of 1211.6 m 2 g −1 and a pore volume of 0.59 cm 3 g −1 , acquires oxygen-containing functional groups on the surface of framework and functionalizes for the chemical adsorption of elemental sulfur. Under N 2 atmosphere (flow rate ∼ 60 mL min −1 ) the longer is the sulfur-loading time, the lower value is the total sulfur content of carbon-sulfur composite and the higher percentage of sulfur embedded within the micropores. At a sulfur-loading time of ∼10 h, the resulting C-S-10 composites have a total sulfur content as low as 50.0 wt% (44.8% in micropores) but exhibit the better electrochemical performances than C-S-6 composites formed at 6 h (sulfur ∼ 58.8 wt%, 29.4% in micropores). Therefore, aside from the structural properties of porous carbon, an optimized sulfur-loading time, as well as the chemical binding between carbon host and sulfur, should be considered to develop high-performance cathode materials for liquid electrolyte lithium-sulfur (Li-S) batteries. [ABSTRACT FROM AUTHOR]

Electrochemical corrosion behavior of platinum coated (Pt-coated) lanthanum doped titanium-zirconium-molybdenum alloy (La-TZM alloy) was studied in this paper. La-TZM alloy plates were fabricated using powder metallurgy and rolling technique, and platinum was coated on their surfaces by using electroplating. Corrosion behavior of Pt-coated La-TZM alloy samples were investigated in neutral and alkaline medium while the Cl − concentrations keep invariant, which was quantitatively analyzed using potentiodynamic polarization, scanning electron microscope and energy spectrum techniques. Results show that the Pt-coating can improve the corrosion resistance of the La-TZM alloy. Pt-coating on La-TZM alloy can effectively hinder the matrix alloy electrochemical corrosion during different corrosion mediums. In addition, the Pt-coating on La-TZM alloy in a neutral medium is more corrosion resistant than that in an alkaline medium. Pt-coating can effectively hinder the Cl − destroys the corrosion formed on the surface passivation film, OH − and Cl − double erosion promoted La-TZM alloy intergranular corrosion increased during the electrochemical corrosion processes. [ABSTRACT FROM AUTHOR]

Hydrogen production from electrochemical water dissociation has been considered as a facile and promising approach to address energy related crisis in the world. In this regard, development of high performance, stable, and cost-effective catalysts for full water splitting is highly demanded. In this work a high performance electrocatalyst based on commercially available Tin oxide nanoparticles mixed with carbon nanotubes (CNT) is presented for electrocatalytic water splitting. The catalyst prepared through facile dropped casting method and obtained a high electrocatalytic activity for full water splitting. One of the key important parameters in water splitting is producing hydrogen/oxygen at high rate under long term stability. This is problematic because it would result in catalyst degradation and performance fallen. However, herein, the prepared electrocatalyst demonstrated a high stability of more than 10 h operation under a high applied current density of 100 mA.cm−2 for hydrogen evolution reaction. For the both hydrogen and oxygen, the prepared catalyst (SnO 2 /CNT coated on carbon paper) delivered the current density of 10 mA.cm−2 at a low overpotentials of 150 mV and 250 mV, respectively. Our observations validate the excellent capability in significantly modifying the catalytic activity of transition metal compound catalysts with carbon nanostructures. [Display omitted] • A synergetic effect of CNT and SnO 2 combination on the electrocatalytic performance was observed. • A lower overpotentials required to reach high current densities, along with high stability at high current. • CNT hybridization with SnO 2 influenced the Volmer step of HER. Also, the adsorption of oxygen and hydrogen affected. • The open structure accelerated the gas detachments during OER or HER, influencing the performance of the system. [ABSTRACT FROM AUTHOR]

A Cu–Zn–Sn (CZT) precursor film on Mo/soda lime glass was electrochemically co-deposited in a stirred citrate solution and further annealed and selenized at elevated temperatures. Modern x-ray diffraction and Raman spectroscopy methods have been used for determination of the phase composition of as-deposited, preliminary annealed and selenized precursor films. It has been determined that the as-deposited CZT film contains up to four metallic phases: the hexagonal η-Cu 6.26 Sn 5 , tetragonal Sn, cubic γ-Cu 5 Zn 8 , and cubic β′-CuZn phase. During the CZT preliminary annealing at a temperature of 230 °C pure tin only melted and crystallized into the tetragonal Sn phase when the sample was naturally cooling down. When preliminary annealing was conducted at a temperature of 350 °C the whole pure tin was used for the formation of Sn solid solutions both in η-Cu 6.26 Sn 5 and γ-Cu 5 Zn 8 phases. However, a segregation of Sn was found out after ageing of pre-annealed precursor for 2 days. XRD studies of CZT films selenized at temperatures 350–500 °C have shown that formation of Cu 2 ZnSnSe 4 (CZTSe) started at temperatures of about 400 °C, however, the selenized film contained a large quantity of ZnSe phase and somewhat less that of CuSe. The amount of ZnSe decreased with selenization temperature until it became undetectable by XRD at a temperature of 500 °C. The paper also deals with the possible routes of Cu 2 ZnSnSe 4 formation. [ABSTRACT FROM AUTHOR]

This paper presents a novel TiO 2 -Graphene composite film one-step preparation method by electrochemical synthesis. The films were prepared on a Ti substrate by electrochemical deposition from a GO and Ti (IV) aqueous solution. For comparison, pure TiO 2 on a Ti substrate was obtained by the same electrochemical method. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, photoluminescence and ultraviolet–visible spectrophotometry. The photocatalytic properties of the films were investigated for the discoloration of Reactive Yellow 145 dye. The results showed that the TiO 2 -Graphene oxide composite film presented photocatalytic activity almost twice as high as that observed for the TiO 2 film. In addition, the TiO 2 -Graphene oxide composite film presented better stability and recyclability, retaining its catalytic efficiency (≈70%) even after 15 cycles. [ABSTRACT FROM AUTHOR]

We report in this paper, a facile hydrothermal route for the preparation of CdS nanocrystals at room temperature (RT). Composition, structure and morphology of the products were analyzed and characterized by X-ray diffraction (XRD) confirms that the hydrothermal treatment at 180 °C for periods ranging from 0 to 1440 min caused no significant modification of the long range order structure subjected to hydrothermal treatment. From the XRD analysis the diffraction peaks pertaining to 26.75°, 43.89° and 52.34° are attributed to the (111), (220) and (311) planes of cubic zinc blende structure. The Photoluminescence (PL) spectra are dominated by a strong narrow band edge emission tunable in the blue region of the visible spectra indicating the narrow size distribution of CdS nanocrystals. TEM observation shows that the CdS nanocrystals synthesized by hydrothermal synthesis are well dispersed and the average crystallite size was found to be ∼10 nm. The confocal microscopic studies reveal that each flower like spheres is due to Ostwald's ripening with numerous nanoparticles aggregating a surface. [ABSTRACT FROM AUTHOR]

(GeTe 4 ) 100− x Ag x and (GeTe 4 ) 100− x (AgI) x glasses were prepared by a melting-quenching method. The glass electrical conductivity was investigated by both electrochemical impedance spectroscopy at different temperatures from 283 K to 333 K and four-probe method at room temperature (293 K). Meanwhile, as a major factor determining the electrical conductivity of a solid, optical band gap was also studied. By comparing the electrical conductivity values and glass optical band gap evolution, it was found that (GeTe 4 ) 100− x Ag x glasses are mainly electronic conductive. On the other hand, the electrical conductivities of (GeTe 4 ) 100− x (AgI) x glasses firstly show a monotonic decrease by increasing AgI up to 15 mol.%, and then an increase when the AgI content is higher than 15 mol.%. The activation energy E a and the pre-exponential factor σ 0 show apparent turning point when AgI content is 15 mol.%, signifying a conductivity mechanism change. In this paper, correlations between the conductivity and hypothetical structures in (GeTe 4 ) 100− x Ag x and (GeTe 4 ) 100− x (AgI) x glasses are done and the importance of the Ag role is underlined. [ABSTRACT FROM AUTHOR]