Preparation of carbon nanotube and graphene doped polyphenylene sulfide flexible film electrodes and the electrodeposition of Cu2O nanocrystals for hydrogen-generation

Through annealing and electrochemical reduction methods, we successfully fabricates reduced graphene oxide layer (RGOL) modified carbon nanotube and reduced graphene oxide (CNT + RGO) doped polyphenylene sulfide (PPS) flexible thin film electrodes. These composite structure films can not only overcome the brittle nature of PPS, but also make good use of the thermal stability of PPS. Furthermore, carbon nanotube and reduced graphene oxide enhance the electrical conductivity of the composite films. Truncated octahedral and cuboctahedral Cu₂O nanocrystals are synthesized on RGOL modified CNT + RGO doped PPS (RGOL@PPS/CNT + RGO) composite film by a facile electrodeposition method without using any surfactants or external heating. RGOL on the PPS/CNT + RGO substrate facilitates the formation of Cu₂O morphology. The obtained Cu₂O composite film shows a superior ability for the hydrogen evolution reaction (HER) compared with other Cu₂O electrocatalysts. The Cu₂O with a smaller loading less than 0.04 mg cm^?2 on the composite film exhibits excellent HER activities with a low onset potential of 0.05 V and large current densities. The results of the HER performance indicates that the RGOL@PPS/CNT + RGO composite film has a potential application in flexible hydrogen-producing devices.     

Mechanistic investigation on tuning the conductivity type of cuprous oxide (Cu2O) thin films via deposition potential

The conductivity type of cuprous oxide (Cu₂O) thin films is tuned by controlling the deposition potential of an electrochemical process in an acid cupric acetate solution containing sodium dodecyl sulfate. The morphology and chemical composition of the deposited Cu₂O films are studied by SEM, XRD and XPS. The change of the conductivity type of Cu₂O films is further studied through zero-bias photocurrent and Mott-Schottky measurements. The results indicate that the Cu₂O films behave as n-type semiconductors when the overpotentials are low (potentials higher than ?0.05 V) and p-type semiconductors when the overpotentials are high (potentials lower than ?0.10 V). The transformation of conductivity from n-type to p-type comes from the competition reactions between forming Cu₂O and forming metallic Cu from Cu²⁺. When the potential is lower than ?0.10 V, most of Cu²⁺ are consumed by the growth of metallic Cu at the film/solution interface, so that the Cu²⁺ provided to grow Cu₂O film are insufficient and copper vacancies form in the film, leading to the p-type conductivity.     

Surface modification of aligned TiO2 nanotubes by Cu2O nanoparticles and their enhanced photo electrochemical properties and hydrogen generation application

In this work, we report the synthesis of cuprous oxide (Cu₂O) nanoparticles modified vertically oriented aligned titanium dioxide (TiO₂) nanotube arrays through wet chemical treatment of TiO₂ nanotubes and their multi-functional application as enhanced photo electrochemical and hydrogen generation. The synthesized samples were characterized by X-ray diffraction, SEM, TEM, and UV–Vis spectroscopy. The structural characterization revealed that the admixed Cu₂O nanoparticles on the TiO₂ surface did not alter its crystalline structure of vertically oriented aligned TiO₂ nanotube. The photocatalytic performance and hydrogen generation of as synthesized Cu₂O nanoparticles modified aligned TiO₂ nanotube was found to highly depend on the Cu₂O content. The optical characterizations reveal that the presence of Cu₂O nanoparticles extends its absorption into the visible region which improves the photocurrent density in comparison to pristine aligned TiO₂ nanotubes electrodes due to enhanced photoactivity and better charge separation. The optimum photocurrent density and hydrogen generation rate has been found to be 3.4 mA cm^?2 and 127.5 μmole cm^?2 h^?1 in 1 M Na₂SO₄ electrolyte solution under 1.5 AM solar irradiance of white light with illumination intensity of 100 mW cm^?2.     

Fabrication of cost-effective non-noble metal supported on conducting polymer composite such as copper/polypyrrole graphene oxide (Cu2O/PPy–GO) as an anode catalyst for methanol oxidation in DMFC

Cost-effective non-noble metal catalysts are of key significance to the successful use of direct methanol fuel cells (DMFCs) for electricity generation. Herein, cuprous oxide nanoparticles (Cu₂O NPs) supported graphene oxide (GO), polypyrrole (PPy) and polypyrrole–graphene oxide (PPy–GO) matrices were prepared using borohydride reduction method. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectra, Zeta potential and transmission electron microscopy (TEM). The elemental analysis of the composites was done by energy dispersive X-ray spectroscopy (EDX). Cu₂O NPs were homogeneously dispersed and strongly anchored on the PPy grafted GO matrix and this was examined through morphological analysis. The Cu₂O/PPy–GO (80:10:10) NPs exhibited noticeable improvement in electrochemical performance in comparison to pure graphene oxide (GO) and pure PPy supported Cu₂O NPs catalyst and revealed the peak current density of 300 μA cm^?2 at +0.68 V. The Cu₂O/PPy–GO system demonstrated higher current density and also exhibited greater stability in comparison to the commercial Pt–Ru/C catalyst as characterized by chronoamperometry (CA) analysis. This prospective nano-catalyst showed higher I_F/I_B ratio (26%, 8.6% and 19%) compared to the corresponding catalyst systems of Cu₂O/GO, Cu₂O/PPy and Pt–Ru/C. In direct methanol fuel cell (DMFC), the efficiency of Cu₂O/PPy–GO nano-catalyst system as an anode catalyst for methanol oxidation reaction (MOR) was investigated and the result revealed a maximum current density of 155 mA cm^?2 at +0.2 V and power density of 31 mW cm^?2. Hence, Cu₂O/PPy–GO NPs are a cost-effective alternative for Pt–Ru/C system to execute practical application in DMFC.     

Evaluation of hydrogen evolution reaction on chemical bath deposited Cu2O thin films: Effect of copper source and triethanolamine content

The chemical bath deposition method was used to deposit thin films of cuprous oxide. The effect of copper source and triethanolamine content on the optical, morphological, structural, electrochemical and photoelectrochemical properties of the thin films for the development of photocathodes for hydrogen production was investigated. Triethanolamine promotes the complexing of Cu⁺ ions independent of the copper source used, its increase promotes thicker films due to better growth control and reduction of rapid Cu₂O precipitation in the bulk solution. The increase in thickness promoted a change in preferential orientation from (111) plane to (200) plane, which also influenced and reduced the conductivity because there is a decrease in disorder (Urbach energy E_U). The thickness also varied due to copper source used, reaching the thickest films with copper nitrate while the thinnest films with copper acetate, this tendency is in agreement with their solubility in water. The lower solubility reduces the complexing of Cu ⁺ ions which promotes the Cu₂O precipitation in the bulk solution, limiting the growth of the film. Also, electrical properties varied (measured as disorder E_U) with copper source. The most conductive being the thin films deposited with copper acetate and nitrate while the most resistive being the films deposited with copper sulphate. Very little variation in optical properties was observed, estimating the band gap in the range of 2.62–2.66 eV, while high absorption coefficient (>10⁵ cm^?1) was calculated below the absorption edge (460–470 nm). All thin films showed p-type semiconducting behavior with a flat band potential in the range of ?0.10 to 0.18 V (Ag/AgCl sat electrode), which confirms their ability to work as photocathodes for hydrogen production. The best photoelectrochemical performance was observed with the thinnest films, which also are the most conductive and present the highest values of absorption coefficient.     

Photoelectrochemical characteristics of CuO films with different electrodeposition time

This paper explores the effect of electrodeposition time on microstructure, optical, and photoelectrochemical properties of CuO films. CuO films were electrochemically deposited on tin-doped indium oxide (ITO) substrates using a Cu₂O electrodeposition method followed by annealing at 550 °C for 2 h. The electrochemical deposition was carried out at different times (300, 600, 1200, and 1800 s) utilizing a copper sulfate pentahydrate and lactic acid solution. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to perform phase and microstructure analysis. Photoluminescence (PL) studies confirmed an increase in emission intensities with increasing deposition time. In addition, a significant change was observed in photoelectrochemical properties of the film by varying the deposition time. The film deposited for 600 s showed a high photocurrent density of ?0.55 mA cm^?2 at ?0.5 V. Moreover, a lowest resistance from electrochemical impedance spectroscopy (EIS) was recorded for the films electrochemically deposited for 600 s.     

Chemical bath deposition synthesis of TiO2/Cu2O core/shell nanowire arrays with enhanced photoelectrochemical water splitting for H2 evolution and photostability

In this study, we have developed a facile chemical bath deposition (CBD) method to grow p-type Cu₂O nanoparticles on n-type TiO₂ nanowire arrays (TiO₂ NWAs) to fabricate TiO₂/Cu₂O core/shell heterojunction nanowire arrays (TiO₂/Cu₂O core/shell NWAs). When used as photoelectrode, the fabricated TiO₂/Cu₂O core/shell NWAs show improved photoelectrochemical (PEC) water splitting activity to pure TiO₂ NWAs. The effects of the CBD cycle times on the PEC activities have been studied. The TiO₂/Cu₂O core/shell heterojunction nanowire array photoelectrode prepared by cycling 5 times in the CBD process achieves the highest photocurrent of 2.5 mA cm^?2, which is 2.5 times higher than that of pure TiO₂ NWAs. In addition, the H₂ generation rate of this photoelectrode reaches to 32 μmol h^?1 cm^?2, 1.7 times higher than that of pure TiO₂ NWAs. Furthermore, the TiO₂/Cu₂O core/shell heterojunction nanowire array photoelectrode shows excellent photostability and achieves a stable photocurrent of over 2.3 mA cm^?2 during long light illumination time of 5 h. The enhanced photocatalytic activity of TiO₂/Cu₂O core/shell heterojunction nanowire array photoelectrode is attributed to the synergistic actions of TiO₂ and Cu₂O for improving visible light harvesting, and efficient transfer and separation of photogenerated electrons and holes.     

Layered perovskite LnBa0.5Sr0.5Cu2O5+δ (Ln = Pr and Nd) as cobalt-free cathode materials for solid oxide fuel cells

Cobalt-free layered perovskite LnBa_0.5Sr_0.5Cu₂O_5+δ (Ln = Pr and Nd, PBSC and NBSC) powders are prepared using combined citrate and EDTA complexing method. The performance of PBSC and NBSC cathode materials are evaluated for solid oxide fuel cells (SOFCs). Two oxidation states (Cu²⁺/Cu⁺) for Cu ions exist in LnBa_0.5Sr_0.5Cu₂O_5+δ oxides. The main valence of Pr ions in PBSC is 3+. The average thermal expansion coefficients (TECs) of PBSC and NBSC are 14.2 and 14.6 × 10^?6 K^?1 between 30 and 950 °C, which are similar to the TECs of La_0.9Sr_0.1Ga_0.8Mg_0.2O_3?δ (LSGM) intermediate-temperature electrolyte. The electrical conductivity of PBSC is slightly higher than that of NBSC. At 800 °C, the polarization resistance (R_p) values of the PBSC and NBSC cathodes on the LSGM electrolyte are 0.043 and 0.057 Ω cm², respectively. The electrolyte-supported single cells were prepared by using PBSC and NBSC as cathode, LSGM as electrolyte (300 μm thickness), Ce_0.9Sm_0.1O_1.95 (SDC) as interlayer and Ni/SDC as anode. At 850 °C, the maximal power densities are obtained as 681 and 651 mW cm^?2 for PBSC and NBSC cathodes.     

Synthesis of high performing Cu0.31Ni0.69O/rGO hybrid for oxygen reduction reaction in alkaline medium

In this feature article, Cu_0.31Ni_0.69O nanoparticles were assembled on reduced graphene nanosheets (Cu_0.31Ni_0.69O/rGO) by a simple hydrothermal method. The structural characterizations confirm that the synthesized nanoparticles with an average size around 9 nm are densely and uniformly assembled on the reduced graphene oxide (rGO) nanosheets. The electrochemical measurements demonstrate that the as-synthesized Cu_0.31Ni_0.69O/rGO catalyst exhibits excellent catalytic performance for oxygen reduction reaction with high cathodic current density (2.08 × 10⁻⁴ mA/cm²), positive onset potential (−0.21 V), low H₂O₂ yielding rate (less than 2.5%) and long-term running stability. The rotating disk and rotating ring-disk electrode measurements proved that the oxygen reduction reaction occurs on Cu_0.31Ni_0.69O/rGO through a high efficient four-electron pathway. The Cu_0.31Ni_0.69O/rGO nanoparticles shows great potential to be promising noble metal-free catalyst for cathodes of alkaline fuel cells.     

Facile fabrication of porous Ti2Nb10O29 microspheres for high-rate lithium storage applications

Ti₂Nb₁₀O₂₉ (TNO) microspheres are fabricated combining a solvothermal method with a subsequent heat-treatment. Structural and morphological properties of the as-prepared material have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption. The electrochemical performance is evaluated by performing cyclic voltammograms and galvanostatic discharge/charge tests. The electrochemical characterization demonstrates that the as-prepared TNO microspheres exhibit a good electrochemical performance with a discharge capacity of 185 mAh g^?1 after 200 cycles and a capacity retention of 94% at 10 C. Furthermore, since TNO may react with Li at a voltage above 1.0 V vs. Li⁺/Li, TNO microspheres could be the promising high-power anode materials for 2 V vs. Li⁺/Li lithium-ion batteries applications.     

Preparation and photocatalytic H2-production on α-Fe2O3 prepared by sol-gel

In this work, the hematite α-Fe₂O₃ was synthesized by sol-gel method and characterized by X-ray diffraction and optical properties. The XRD patterns realized at different temperatures, show that pure hematite is obtained above 500 °C. The diffuse reflectance gives respectively direct and indirect optical transitions at 2.17 and 2.04 eV, in agreement with the red color. The capacitance measurement of α-Fe₂O₃ indicates p type behavior with a conduction band (?1.14 V vs. SCE), more cathodic than the H₂ evolution (～?0.8 V vs. SCE). The oxide was successfully tested for the hydrogen production under visible irradiation (29 mW cm^?2). α-Fe₂O₃ is photo-electrochemically stable in alkaline medium by hole consumption reactions involving X^2? (= SO₃^2? and S₂O₃^2?) as hole scavengers. The best photocatalytic activity for H₂ production was obtained on α-Fe₂O₃, calcined at 500 °C, in (Na₂S₂O₃ 0.025 M, pH ～ 13), with an average evolution rate of 0.015 cm³ h^?1 (mg catalyst)^?1 and a quantum efficiency of 0.26%. The system shows a tendency toward saturation, due to the competitive reduction of end products with the water reduction and the cathodic shift of the H₂ potential.     

Gold protective layer decoration and pn homojunction creation as novel strategies to improve photocatalytic activity and stability of the H2-evolving copper (I) oxide photocathode

p-type Cu₂O (p-Cu₂O) is a promising candidate for engineering of photocathodes for solar H₂ generation but it suffers from the photo-induced corrosion process. In this work, we report on the two new strategies to overcome the photo-induced corrosion and to enhance the photocatalytic activity of the p-Cu₂O photocathode: (i) a 60-to-300-nm-thick Au layer prepared by sputtering was used as a protective layer to the p-Cu₂O electrode; (ii) a thin layer of n-type Cu₂O was deposited onto the p-Cu₂O electrode surface before sputtering the Au protective layer. For the latter, as a direct result, a pn-Cu₂O homojunction was formed that was then protected by the Au thin layer. The pn-Cu₂O homojunction helps to enhance the charge separation within the Cu₂O electrode, consequently contributes to the enhancement of the photocatalytic activity. Under the standard 1 Sun irradiation, the best Au-protected pn-Cu₂O photocathode showed an onset photovoltage of +0.55 V vs. Reversible Hydrogen Electrode (RHE), and a photocurrent density of 0.76 mA/cm² at an applied potential of 0 V vs. RHE that remained more than 50% after 3 min of operation. Whereas, the bare p-Cu₂O showed a photocurrent density of 0.3 mA/cm² that was completely degraded after 1 min of operation under the identical conditions.     

Characterization and application of self-assembled thin films of polyelectrolytes/TiO2/CdSe for hydrogen production

Photocatalysis of water to produce hydrogen gas over titanium dioxide or other semiconductor films, known as water splitting, is a promising alternative using solar energy to obtain a clean fuel. Self-assembled thin films (SATFs) from the physical adsorption of polyelectrolytes and inorganic semiconductor nanoparticles are created by an inexpensive and non-polluting process that gives films with high molecular organization. The aim of this work was to fabricate and characterize SATFs via the layer-by-layer technique using the polyelectrolytes polyallylamine hydrochloride (PAH), poly(acrylic acid) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in combination with titanium dioxide and CdSe nanoparticles and evaluate the application potential of these systems to produce hydrogen gas by solar radiation. The characterization of the SATFs showed that films with positive surface charge present favourable conditions for incorporation of negatively charged CdSe nanoparticles and that alkaline condition favour agglomeration of TiO₂ nanoparticles. The best system was composed of (PAH + CdSe) and (PEDOT:PSS + TiO₂ 100% anatase) in alkaline medium. With a hydrogen gas average production rate of 0.350 μmol h^?1 cm^?2, the maximum number of layers was optimized at 120 layers, beyond which there was a decrease in photocatalytic activity, reducing the average production rate to 0.07 with the SATF of 160 layers. Moreover, the presence of CdSe increased the hydrogen gas production by 75% when compared to the film containing only titanium dioxide.     

Rare-earth oxide–Li0.3Ni0.9Cu0.07Sr0.03O2-δ composites for advanced fuel cells

Recent development on electrolyte-free fuel cell (EFFC) holding the same function with the traditional solid oxide fuel cell (SOFC) but with a much simpler structure has drawn increasing attention. Herein, we report a composite of industrial grade rare-earth precursor for agriculture and Li_0.3Ni_0.9Cu_0.07Sr_0.03O_2-δ (RE–LNCS) for EFFCs. Both structural and electrical properties are investigated on the composite. It reveals that the RE–LNCS possesses a comparable ionic and an electronic conductivities, 0.11 S cm^?1 and 0.20 S cm^?1 at 550 °C, respectively. An excellent power output of 1180 mW cm^?2 has been achieved at 550 °C, which is much better than that of the conventional anode/electrolyte/cathode based SOFCs, only around 360 mW cm^?2 by using ionic conducting rare-earth material as the electrolyte. Engineering large size cells with active area of 25 cm² prepared by tape-casting and hot-pressing gave a power output up to 12 W. This work develops a new functional single layer composite material for EFFCs and further explores the device functions.     

Crossed FeCo2S4 nanosheet arrays grown on 3D nickel foam as high-efficient electrocatalyst for overall water splitting

Great efforts in developing low-cost, highly efficient and stable electrocatalysts are to tune the chemical compositions and morphological characteristics for enhancing efficiency of water splitting. In this communication, FeCo₂S₄ nanosheet was grown in situ on nickel foam (FeCo₂S₄/NF) via a facile hydrothermal sulfidization method and served as a high-efficient bifunctional electrocatalyst for overall water splitting. As-synthesized FeCo₂S₄/NF self-supported electrode delivers 20 mA cm^?2 at an overpotential of 259 mV toward OER and 10 mA cm^?2 at an overpotential of 131 mV toward HER in alkaline media. Moreover, when used as both anode and cathode in a two-electrode electrolyzer, only a small cell voltage of 1.541 V is needed to afford a current density of 10 mA cm^?2 for overall water splitting. Bifunctional electrode FeCo₂S₄/NF also revealed a distinguished electrochemical durability during a 12 h stability test at 1.63 V, which would provide a promising water splitting installation for commercial hydrogen production.     

Copper molybdenum sulfide: A novel pseudocapacitive electrode material for electrochemical energy storage device

The ever-growing demand for energy storage devices necessitates the development of novel energy storage materials with high performance. In this work, copper molybdenum sulfide (Cu₂MoS₄) nanostructures were prepared via a one-pot hydrothermal method and examined as an advanced electrode material for supercapacitor. Physico-chemical characterizations such as X-ray diffraction, laser Raman, field emission scanning electron microscope with elemental mapping, and X-ray photoelectron spectroscopy analyses revealed the formation of I-phase Cu₂MoS₄. Electrochemical analysis using cyclic voltammetry (CV), charge-discharge (CD) and electrochemical impedance spectroscopy (EIS) showed the pseudocapacitive nature of charge-storage via ion intercalation/de-intercalation occurring in the Cu₂MoS₄ electrode. The Cu₂MoS₄ electrode delivered a specific capacitance of 127 F g^?1 obtained from the CD measured using a constant current density of 1.5 mA cm^?2. Further, Cu₂MoS₄ symmetric supercapacitor (SSC) device delivered a specific capacitance of 28.25 F g^?1 at a current density of 0.25 mA cm^?2 with excellent rate capability. The device acquired high energy and power density of 3.92 Wh kg^?1 and 1250 W kg^?1, respectively. The Nyquist and Bode analysis further confirmed the pseudocapacitive nature of Cu₂MoS₄ electrodes. The experimental results indicate the potential application of Cu₂MoS₄ nanostructures as a novel electrode material for energy storage devices.     

Crystal structure,electrical and electrochemical properties of Cu co-doped Pr1.3Sr0.7NiO4+δ mixed ionic-electronic conductors (MIECs)

Room temperature crystal structure, electrical properties and electrochemical properties in the temperature range 25–700 °C of Cu co-doped Pr_1.3Sr_0.7NiO_4+δ prepared by acetate combustion is investigated from intermediate temperature solid oxide fuel cell cathode viewpoint. The Pr_1.3Sr_0.7Ni_1?xCu_xO_4+δ (PSNCO) solid solutions have a tetragonal I4/mmm K₂NiF₄-type structure which consists of a (Pr_1.3Sr_0.7) (Ni_1.xCu_x)O₃ perovskite unit and a (Pr_1.3Sr_0.7)O rock salt unit in the whole compositional range 0 ≤ x ≤ 0.4. A reduction in bond-length of Ni/Cu-O resulting from PSNCO lattice contraction eases hop of small polaron from Ni³⁺ to Ni²⁺/Cu²⁺ in (Ni_1?xCu_x)-O layer with low activation energy, which increases electron conductivity. The maximum electronic conductivity (σ = Ω cm^?1) with minimum activation energy (E_a = eV) is observed at x = 0.3. Lattice expansion along c-direction owing to Cu²⁺ doping facilitates hop of O^2? from its occupied interstitial site (O₃) to nearby equivalent site assisted by anisotropic thermal motion of apical oxygen O2 resulting in increase in ionic conductivity. The minimum polarization resistance value (R_p = 0.13 (2) Ω cm²) and activation energy (E_a = 1.321 (5) eV) at x = 0.3 is attributed to high electronic and ionic conductivities compared to other compositions. Complex impedance spectroscopy studies suggest that the ORR is co-limited by O^2? diffusion and O₂ surface exchange.     

Design and preparation of CdS/H-3D-TiO2/Pt-wire photocatalysis system with enhanced visible-light driven H2 evolution

In recent years, tremendous efforts have been devoted to develop new photocatalyst with wide spectrum response for H₂ generation from water or aqueous solution. In this work, CdS nanoparticles (NPs) have been immobilized on hydrogenated three-dimensional (3D) branched TiO₂ nanorod arrays, resulting in a highly efficient photocatalyst, i.e, CdS/H-3D-TiO₂. In addition, electrochemical reduction of H⁺ ion is identified as a limiting step in the photocatalytic generation of H₂ at this catalyst, while here a Pt wired photocatalysis system (CdS/H-3D-TiO₂/Pt-wire) is designed to overcome this barrier. Without the application of potential bias, visible light photocatalytic hydrogen production rate of CdS/H-3D-TiO₂/Pt-wire is 18.42 μmol cm^?2 h^?1, which is 11.2 times that of CdS/H-3D-TiO₂ without Pt (1.64 μmol cm^?2 h^?1). The Pt wire acts as an electron super highway between the FTO substrate and H⁺ ions to evacuate the generated electrons to H⁺ ions and catalyze the reduction reaction and consequently generate H₂ gas. This work successfully offers a novel direction for dramatic improvement in H₂ generation efficiency in photocatalysis field.     

Enhanced performance of direct peroxide–peroxide fuel cells by employing three-dimensional Ni and Co@TiC nanoarrays anodes

Thorn-like Ni@TiC NAs and flake-like Co@TiC NAs electrodes without any conductive agent and binder are simply fabricated by the potentiostatic electrodeposition of Ni and Co catalysts on the TiC nanowire arrays (NAs). The electrocatalytic activity of H₂O₂ oxidation on the Ni@TiC NAs electrodes is better than that on the Co@TiC NAs electrodes. The Ni@TiC NAs electrodes demonstrate a rough surface and have many nano-needles on the rod edges, which assures the high utilized efficiency of Ni catalysts. These particular three-dimensional structures may be very suitable for H₂O₂ electrooxidation. The anodic current of Ni@TiC NAs anode reaches 0.32 A cm^?2 at 0.3 V in 1.0 M H₂O₂ + 4 M KOH solution. The DPFCs employing Ni@TiC NAs anodes display the peak power density of 30.2 mW cm^?2 and open circuit voltage of 0.90 V at 85.1 mA cm^?2 with desirable cell stability at 10 mL min^?1 flow rate and 20 °C, which is much higher than those previously reported.     

Electrochemical performance of gel polymer electrolyte with ionic liquid and PUA/PMMA prepared by ultraviolet curing technology for lithium-ion battery

A series of diethylethyletherylmethanamine bis(trifluoromethanesulfonyl)imide (DEEYTFSI) ionic liquid gel polymer electrolyte based polyurethane acrylate (PUA)/poly(methyl methacryltae) (PMMA) matrix with different contents of DEEYTFSI, PUA and LiTFSI were prepared via ultraviolet (UV) curing system. Electrochemical performances of the gel polymer were studied by electrochemical station and charge–discharge system. The gel polymer electrolyte with 19 wt.% DEEYTFSI obtained a maximum conductivity σ of 2.76 × 10^?4 S cm^?1 and the transference number t_Li+ of ～0.22 at room temperature. 19 wt.% DEEYTFSI caused the easier transferring of lithium ions due to less apparent activation energy E_a of 21.1 kJ mol^?1. The DEEYTFSI/LiTFSI/PUA/PMMA electrolyte had good compatibility with LiFePO₄ cathode. The DEEYTFSI/LiTFSI/PUA/PMMA electrolyte with the electrochemical window of 4.70 V was enough stability for being the electrolyte material of lithium battery. The Li/19 wt.% DEEYTFSI–LiTFSI–PUA–PMMA/LiFePO₄ coin-typed cell cycled at 0.1 C presented 95% efficiency on the 50th cycle.