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Li-metal is an attractive anode material for next-generation batteries owing to its high capacity and low reduction potential. Unfortunately, it undergoes dendritic growth, which limits its develop...

Although quasi-solid-state fiber-shaped Zn-polyaniline batteries (Fs-ZPBs) are safe and potentially wearable power sources, they exhibit severe capacity degradation due to the inherently low electrolyte conductivity, soluble quinone formation in the cathode, and anode corrosion. In this study, these problems are mitigated by supplementing a polyvinyl alcohol-based gel-type electrolyte with methanesulfonic acid, which forms intermolecular hydrogen bonds to connect polyvinyl alcohol chains with each other and link the polyaniline surface with the electrolyte. The establishment of these linkages increases the ionic conductivity of the electrolyte and enhances charge transfer at the polyaniline/electrolyte interface. The relatively large molecular size of methanesulfonic acid hinders the access of water to the active materials (polyaniline and Zn) while allowing polyaniline to be efficiently doped with small-radius Cl− anions. The effects of dual anion doping and water capture suppress polyaniline degradation and Zn corrosion, resulting in excellent battery performance, namely, 88.1% capacity retention after 2000 cycles and 92.7% capacity retention after 500 bending cycles at a 2.5 mm bending radius. Furthermore, an all-carbon-yarn Fs-ZPB is developed for applications requiring practical wearability.

Lithium-ion capacitors (LIC) is believed to be an ideal option in certain application as energy storage device due to its properties either possessing high energy density (four times higher than electrical double-layer capacitor) or having as much power density as a supercapacitor. In this study, a biomass-based activated carbon (WHAC) was prepared by using the water hyacinth plant through the activation process utilizing a chemical activating agent, KOH. The water hyacinth was carbonized at 500 °C for a 1 h holding time with a ramping temperature of 10 °C/min. Then, the LICs electrode is constructed by two different types of electrode, WHAC as the main active material of cathode and lithium titanate oxide (LTO) for the anode. The biomass-derived activated carbon exhibits a high specific surface area of 791.8 m2/g and a high pore volume of 1.13 m3/g. The assembled LiCs shows a reasonable electrochemical performance with a maximum specific capacitance of 1.12 F/g with the highest specific energy of 4.48 Wh/kg and specific power of 34.14 W/kg. This LIC cell is one of the promising candidates for future applications due to its low-cost materials and owns more advantages than typical Lithium-ion Batteries (LIBs).

In recent years, lithium-sulfur (LiS) battery has emerged as promising energy storage systems to replace the conventional lithium ion battery. This battery system uses elemental sulfur as cathodes and Li metal as anodes and possess a higher specific capacity (1,675 mAh/g) compared to that of lithium ion battery. However, some technical problems such as the low conductivity of sulfur, huge volume expansion during cycling and the shuttle effect of polysulfide have prevented this kind of battery system to be commercialized. One method to solve those problems is by using carbon materials as cathode component together with sulfur to form Carbon-sulfur composite cathodes. Carbon materials could improve the electrochemical performance of LiS battery due to the electrical conductivity and highly porous structure. Biomass derived conductive carbon materials have attracted increasing attention on account of their abundance, sustainability, and easy accessibility. Here, onion peel waste has been utilized to synthesize amorphous porous carbon (OPWC) as cathode component for LiS battery. Porous carbons were prepared by using hydrothermal carbonization followed by the chemical activation process using KOH. The carbon-sulfur composites were then obtained after sulfur loading using the melt diffusion method. As obtained OPWC/S composite demonstrates stable cycle performance and a reversible specific capacity of 630 mAh/g after 100 cycles at current density of 0.1 C when used for LiS battery.

A novel flexible fiber-shaped zinc-polyaniline battery (FZPB) is proposed to enhance the electrochemical performance, mass loading, and stability of polyaniline cathodes. To this end, electron-cyclotron-resonance oxygen plasma-modified carbon fibers are employed. During plasma treatment, on the carbon-fiber surface, O

A novel strategy to improve the performance of fibre-shaped dye-sensitized solar cells (FDSSCs) has been successfully implemented using a polar polymer interlayer made of poly(2-ethyl-2-oxazoline) (PEOx). The inclusion of the PEOx interlayer reduces the typical defect sites and interband trap sites that exist on the TiO2-nanotube-based photoanode of the FDSSC. A local built-in electric field, induced by the interfacial intrinsic polarity of the PEOx interlayer, promotes facile photogenerated charge injection/extraction kinetics at the TiO2/dye interface. The negative polarity present on the bottom part of the PEOx chain exhibits an electronic doping-like behaviour, passivating the TiO2 defect sites and reducing trap-assisted recombination, while the positive polarity present on the top part of the PEOx chain provides dye-rich anchoring sites to improve the N719 dye adsorption loading on the TiO2 surface. The charge collection efficiency, short-circuit current density, open-circuit voltage, and fill factor of FDSSCs with the novel TiO2@PEOx photoanodes are superior than those of FDSSCs with traditional TiO2 photoanodes, by approximately 16.94%, 8.57%, 14.08%, and 6.58%, respectively. Consequently, the power conversion efficiency (PCE) of the proposed FDSSC is considerably improved, reaching 11.22%. Thus, the PCE of the proposed FDSSC is improved by approximately 32.16% compared with that of the traditional FDSSC.

Lithium sulfur battery has become one of the promising rechargeable battery systems to replace the conventional lithium ion battery. Commonly, it uses carbon–sulfur composites as cathode materials. Biomass based carbons has an important role in enhancing its electrochemical characteristics due to the high conductivity and porous structures. Here, potato peel wastes have been utilized to prepare porous carbon lithium sulfur battery through hydrothermal carbonization followed by the chemical activation method using KOH. After sulfur loading, as prepared carbon–sulfur composite shows stable coulombic efficiencies of above 98% and a reversible specific capacity of 804 mAh g−1 after 100 cycles at current density of 100 mA g−1. These excellent electrochemical properties can be attributed to the unique structure of PPWC showing mesoporous structure with large specific surface areas. These results show the potential application of potato peel waste based porous carbon as electrode’s materials for lithium sulfur battery.

A hierarchical hollow SnO/SnO2 heterostructure anode surrounded by a dual carbon layer (DCL@SnO/SnO2), inner (host) and outer carbon layers, was successfully designed via a simple hydrothermal method with a single Sn precursor to achieving high-performance Li-ion batteries (LIBs) and Li-ion capacitors (LICs). The carbon nanotube (CNT)-based inner carbon host and an ultrathin outer amorphous carbon layer introduced at the SnO/SnO2 heterostructure had good elasticity and high electrical properties to prevent volume change and ensure fast Li-ion transport during cycling, respectively. Meanwhile, the SnO/SnO2 heterostructure comprising p-type SnO and n-type SnO2 facilitated further fast interfacial Li-ion transfer within the p–n SnO/SnO2 heterojunction anode via the acceleration effect induced by the built-in electric field (BEF). The resulting half cells LIBs consisting DCL@SnO/SnO2 anode shows a high reversible specific capacity of 902.1 mAh g−1 after 500 cycles at a current density of 1400 mA g−1. The specific capacity of 347.04 mAh g−1 was still maintained even at a high current density of 10 000 mA g−1. Moreover, the maximum energy and power density of 125 W kg−1 and 200 Wh kg−1, respectively, were achieved from the half cells LIC comprising DCL@SnO/SnO2 anode (LIC-DCL@SnO/SnO2).

Antiglare and antireflection materials take considerable research attention due to its important role in transparent optical materials for various purposes. In this study, we employed layer-by-layer coating materials consist of SiO2 and TiZrO2 deposited on etched-surface glass substrate using dual electron beam evaporator system. The surface morphology investigated by using scanning electron microscopy (SEM) exhibited the microstructure patterns of glass surface. The cross-sectional image of transmission electron microscopy (TEM) showed uniformly layer-by-layer coating materials with the thickness of ~20–80 nm. The Auger electron spectroscopy (AES) revealed the depth profiles of elemental composition of surface layer-by-layer coating, confirming the presence of elements of SiO2 and TiZrO2 layers. In addition, the layer-by-layer coated glass surface performed the hydrophobic properties with contact angle of 69°. The microstructure surface treatment and layer-by-layer coating have successfully decreased the reflectance (~3%) and increased the transmittance of the treated glass (~91%), opening the possibility for the applications of any optical devices.

This paper mainly focuses on the optimization and design of cathode catalyst layer structure for low-Pt loading membrane assembly electrode. When Pt loading at cathode increased from 0.025 mg cm−2 to 0.4 mg cm−2, the apparent current density of electrode increases gradually, while the electrochemical active surface area (ECSA) and the utilization rate of catalyst show a downward trend. As Pt loading at cathode keeps at 0.1 mg cm−2, commercial Vulcan XC-72 carbon are doped into the conventional Pt/C catalyst layer to improve the utilization rate of the catalyst. The results show that the optimum doping carbon content leads to ∼2 times increase of the thickness of the cathode catalyst layer, and achieves a 32.93% increase of ECSA and better durability than that of conventional catalyst layer. Meanwhile, gas transport in the catalyst layer becomes more difficult with the increase of the amount of doping carbon. Based on this, a more stable Vulcan XC-72@PTFE particles are prepared and selected to construct internal gas transport channels under the same carbon content. The surface contact angle of the catalyst layer is obviously increased to 118.4°. The hydrophobicity of the cathode catalyst layer is enhanced, and the oxygen gain voltage is significantly reduced. The peak power density of PEMFC reaches 539 mW cm−2, which is 30.57% higher than that of one with a conventional catalyst layer structure. Therefore, this work provides a good way for the preparation of high-performance and durable cathode catalyst layer for low-Pt loading membrane assembly electrode.

Liquid metal (In75.4 Ga24.5, LM) with its high electrical conductivity and flexibility at room temperature, has been gradually introduced into printed electronics. However, the low adhesion effect of LM on the common printer paper may restrict its potential value in reducing cost and expanding use. In this study, the surface property of the printer paper has been modified by a wetting method with a coating of micro-size droplets on the paper surface to realize a smooth writing process using the liquid metal ink. The current strategy is expected to enable future flexible electronic circuits on the hard writing substrates.

Herein, the lithiophilicity of Li2O and the capillary action-induced absorption of molten Li are employed to fabricate a hierarchically structured three-dimensional (3D) Li metal electrode comprising Li2O-coated Cu foam (Li2O@Cu foam), the unique structural characteristics of which allow one to suppress Li dendrite formation and confine Li movement within the foam matrix. The lithiophilicity of Li2O@Cu foam is ascribed to the occurrence of in situ interfacial reactions between Li and Cu oxides formed on the surface of Cu foam, and the formation of the Li2O@Li@Cu hierarchical structure is shown to significantly stabilize the interfacial characteristics of the Li metal anode even in harsh electrochemical environments. In addition to being lithiophilic, Li2O@Cu foam allows for homogeneous plating and stripping of Li ions, since the nucleation overpotential of Li2O toward Li ions is low, e.g., the lowest overpotential of 13 mV is observed during Li plating/stripping at 1.0 mA cm−2. At a total capacity of 1.0 mA h cm−2, Li2O@Cu foam exhibits a coulombic efficiency of >99.0% over 150 cycles at 0.5 mA cm−2, whereas a slightly smaller value of ∼97.5% is observed for 100 cycles at 5 mA cm−2.

A porous SnO2 electrode with an ultra-thin 2-nm-thick coating of carbon (SnO2@C) was prepared by a hydrothermal method. The thin carbon layer acted as a relaxant layer alleviating the stress of the volume expansion of the SnO2 active material during intercalation/de-intercalation of lithium ions. The pre-lithiated SnO2@C was employed as an anode material for a non-aqueous lithium-ion capacitor (LIC) using commercial activated carbon (YP-80F) as the cathode. Different states of discharge of the pre-lithiated SnO2@C anode were characterized. At different lithiation degrees, phase transformation and morphology changes of the SnO2 active material affected the electrochemical performance of the LIC system. Shallow lithiation provided insufficient lithium ions to the activated carbon cathode, yielding poor specific energy. Excessively deep lithiation risked severe crack formation on the surfaces of the SnO2 particles, affecting the electrochemical performance at high current densities. Other parameters, including the negative-to-positive electrode mass balance and cut-off voltage control, were also studied regarding their effects on performance. The fabricated LIC (SnO2@C/Activated carbon) delivered a maximum energy of 130 W h kg−1 and a maximum specific power of 6900 W kg−1.

A shape-variable aqueous secondary battery operating at low temperature is developed using Ga68In22Sn10 in wt% liquid metal anode and conductive polymer (polyaniline (PANI)) cathode. While in the GaInSn alloy anode, Ga is the active constituent; Sn and In increase the acid resistance and decrease the eutectic point to -19°C. This enables the use of strongly acidic aqueous electrolytes (here, pH 0.9), thereby improving the activity and stability of the PANI cathode. Consequently, the battery exhibits remarkable excellent electrochemical performance and mechanical stability. The GaInSn–PANI battery operates via a hybrid mechanism of Ga3+ stripping/plating and Cl− insertion/extraction and delivers a high initial capacity of over 324.6 mAh g− 1 and a 52.4% retention rate at 0.2 A g− 1 after 500 cycles, and outstanding power and energy densities of 4300 mW g− 1 and 98.7 mWh g− 1, respectively. Because of the liquid anode, the battery without packaging can be deformed with a small force of several millinewtons without any capacity loss. Moreover, at approximately − 5°C, the battery delivers a capacity of 67.8 mAh g− 1 at 0.2 A g− 1 with 100% elasticity. Thus, the battery is promising as a deformable energy device at low temperatures and in demanding environments.

Laser processing technologies for micro-/nanostructuring of electrode materials have a great potential in improving the electrochemical performance and operational lifetime of lithium-ion cells. Different types of laser structuring were used on different surfaces such as metallic current collectors and thin or thick film electrodes. For thin metallic current collector foils, at anode and cathode sides, the self-organized structuring by laser-induced periodical surface structures and laser interference methods were successfully applied for improving electrode film adhesion and cell impedance. For thin and thick film electrode layers direct laser ablation with structure sizes down to the micrometer range and high aspect ratios were found most powerful in order to create three-dimensional (3D) cell architectures with benefits regarding cell performance and a homogenous wetting of composite electrodes with liquid electrolyte. A huge impact of laser formed 3D batteries regarding capacity retention and cell lifetime at high charging and discharging rates was detected. The impact on diffusion kinetics of laser structured 3D electrodes was studied using classical methods such galvanostatic intermittent titration technique and cyclic voltammetry. A further improvement of 3D battery performance due to an operation in high potential regime and for advanced high energy silicon anode material was achieved by joining of laser structuring and thin-film passivation either of active particles before laser patterning or by passivating of complete 3D electrodes after laser processing. Finally, laser-induced breakdown spectroscopy will be presented as a powerful tool for elemental mapping of entire 2D and 3D electrodes. The impact of 3D architectures on lithium distribution and chemical degradation processes in 2D batteries was investigated and analyzed.

This paper reports use of a 3D porous Cu scaffold as a conductive host in the 3D host-lithium composite anode (HLC) in Li-O2 batteries to decrease local current density and induce uniform Li deposition, and thereby suppress formation of Li dendrites that reduce rate capability and reversibility of the batteries. Furthermore, the influences of HLC and uniform Li-ion flux on Li2O2 formation at the porous cathode were investigated by quantification of Li2O2. The amount of Li2O2 on cathodes changed according to the state of the facing Li anodes; this trend means that the influence of uniform Li-ion flux from the Li metal anode is critical to ensure uniform Li2O2 formation at the cathode. The results confirmed that the HLC ensures uniform formation and decomposition of Li2O2 at the cathode.

This study reports a facile synthesis of ZnO microrods using chemical bath deposition (CBD) for anode materials of lithium-ion batteries (LIB). During the synthesis, we controlled the uniformity, the density, and the diameter growth of ZnO microrods in order to find the optimum conditions. In particular, the effects of annealing temperature on the ZnO microrod morphology, structure, and electrochemical performances were further investigated. The size, alignment, and uniformity of the ZnO microrods were evaluated by scanning electron microscopy (SEM), while structural analysis was performed by X-ray diffraction (XRD) technique. The results showed that the annealing temperatures significantly influenced the ZnO microrod growth. We found the excellent experimental parameters were achieved at annealing temperature of 150 °C (ZnO_150) within 10 min and three seed layers, providing an average diameter of ~ 233.6 nm, crystallite size of 46.01 nm, and the density of 5.05 rods/μm2. Among the other samples, the ZnO_150 microrods delivered the highest initial discharge capacity of 811 mAhg−1 with relatively stable capacity retention of ~ 82% after 80 cycles and excellent rate capability performance.

A single-chamber dynamic membrane microbial fuel cell (SC-DM-MFC) that uses an activated carbon fiber felt (ACFF) non-structural air-breathing cathode was designed for enhanced power production. The effect of COD loading rate (based on glucose substrate) on power production by SC-DM-MFC was studied. In order to investigate the impact of natural breeze on the performance of SC-DM-MFC via increased air flow, the effect of cathode fanning was studied. The maximum power density increased with an increase in the loading rate from 0.6 to 2.0 gCOD L−1 d−1 and fanning the cathode improved the power density from 2023 mW m−3 to 4653 mW m−3. This increase is attributed to the unique nonstructural design of the cathode that allows both sides of ACFF to reduce oxygen in ambient air. Furthermore, the performance of SC-DM-MFC and a dual-chamber dynamic membrane microbial fuel cell (DC-DM-MFC) was compared. In the comparison test, seafood-processing wastewater was used as a substrate because of its high conductivity, biodegradable properties, and rich nutrient content that make it suitable for the growth of electrogenic bacteria. The results show that it is feasible to generate power in DM-MFCs using seafood wastewater and that SC-DM-MFC performs significantly better than DC-DM-MFC. Enhanced power production can be achieved by using an air-breathing ACFF cathode with nonstructural properties.

Despite the advantage of chemical vapor deposition (CVD) for realization of large area epitaxial growth of graphene on transition metal catalysts, both etching and transfer process of CVD-grown graphene sheets still remain a big challenge. Here we demonstrate the formation of multilayer graphene (MLG) sheets tailored from C60 thin films on the top of Si/Ni substrate without etching and transfer steps based on Ni films. This self-assembled process separates the MLG sheets from the conductive Ni catalyst, embarking a possibility for direct characterizations of MLG sheets. The fine-tuned C60 films (30 nm) are transformed into approximately 17 MLG sheets, thus making it large-area MLG sheets for a variety of direct applications.

The performances of fiber dye-sensitized solar cells (FDSSCs), in terms of charge collection efficiency, light-harvesting ability, and structural stability, are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire substrate. The microridge made of several Ti micropits is inserted into TiO2 layer to shorten the photoelectron transport distance from the original place in the TiO2 layer to substrate and to increase the electron transport rate. The Ti micropits are used as light-gathering centers to collect the reflected light. Meanwhile, the Ti nanorods are evenly distributed on the surface of the microridge-coated Ti wire substrate, which increases the contact area between the substrate and the TiO2 layer in order to suppress the electron recombination and scatters the incident light to further improve the light-harvesting ability. Therefore, the charge collection and power conversion efficiencies of the novel FDSSC have been accordingly enhanced by 17.7% and 61.6%, respectively, compared with traditional FDSSC. Moreover, the structural stability of the novel FDSSC has been strengthened.

Hydrogen peroxide is added into the anode methanol fuel as a pro-oxygenic agent to improve the electro-oxidation reaction rate of methanol in low-temperature direct methanol fuel cell. Cyclic voltammetry, electrochemical impedance spectroscopy and steady-state polarization with three-electrode system are used to test the catalytic efficiency with different concentrations of hydrogen peroxide additive. The mechanism of pro-oxygenic activity is revealed by cyclic voltammetry method. The results of electrochemical analysis show that the peak current density and peak power density are the highest when the concentration of hydrogen peroxide additive is 0.1 M at room temperature, increase 12.2% and 34.1% than those of pure methanol solution, respectively. The anode charge transfer resistances reduce gradually as the concentrations of hydrogen peroxide increase from 0 to 0.3 M. The tests under different temperature indicate that the promotion effect of hydrogen peroxide additive is significant at room temperature rather than at high temperature. The results show that hydrogen peroxide can be an effective pro-oxygenic agent for methanol electro-oxidation to improve the anode methanol electro-oxidation reaction of direct methanol fuel cell at room temperature.

Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C60 (PC60) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant superelastic characteristics of the PC60 possess the ability to absorb the stress–strain generated by the Sn nanoparticles and can thus alleviate the problem of their extreme volume changes. Meanwhile, well-dispersed dot-like Sn nanoparticles, which are surrounded by a thin SnO2 layer, have suitable interparticle spacing and multilayer structures for alleviating the aggregation of Sn nanoparticles during repeated cycles. The Ohmic characteristic and the built-in electric field formed in the interparticle junction play important roles in enhancing the diffusion and transport rate of Li ions. SPC-50, a Sn-PC60 anode consisting of 50 wt % Sn and 50 wt % PC60, as confirmed by energy-dispersive X-ray spectroscopy analysis, exhibited the highest electrochemical pe...

In this communication, we present a significant method to fabricate a robust icephobic surface on a flexible polymer substrate. The flexible functional surface is obtained by integrating both soft-lithography and crystal growth methods. Modified by the materials with low surface free energy, the composite surface exhibits a robust superhydrophobicity at not only room temperature but also low temperature. After freezing test, the surface can recover to its original function quickly, which has achieved the level for industrial application, and also performed significant role for enhancing the icephobic theories.

A novel silicon-based robust anti-icing surface with hollow micro-/nano-structured ZnO (HMN) is investigated. The droplet could not freeze in 30 min under low temperature of −15 °C, while that performance fails on the nano-structured and smooth surfaces. The cooling period of temperature fields on liquid droplet and the base are observed, which indicates that the air layer has a significant effect on the performance of the anti-icing surface. The results prove that the hollow micro-structure layer provides much more air than the nano-structured layer and induces the maximum thermal resistance, leading to its icephobic property. In this finding, HMN provides large thermal resistance between the base and liquid droplet and easily realizes long lasting anti-icing performance under lower temperature. This new concept is expected to be used in the fields of anti-icing, superhydrophobicity, insulation, thermal resistance, etc.

Two dual-chamber microbial fuel cells (MFCs) that use dynamic membranes as separators were designed for power production. The performance of these dynamic membrane microbial fuel cells (DM-MFCs) was studied. Compared to an up-flow dual-chamber MFC (U-MFC), at the total volume of 1.1 L, DM-MFCs achieved a higher maximum power density (1923 mW m−3 versus 856 mW m−3). This is because the DM-MFCs have lower membrane resistance (0.6–5.4 Ω), oxygen diffusion coefficient (D0 = 1.8 × 10−7 cm2 s−1), and cost (0.3 USD m−2) than other reported separators; e.g., anion exchange membrane (ACM), cation exchange membrane (CEM), ultrafiltration membrane (UFM), and J-cloth. The dynamic membrane is primarily composed of filamentous bacteria and vorticellidae-like protozoa, which tightly attach to the nylon supporting layer. This microorganism layer consumes most of the dissolved oxygen and prevents oxygen transfer from the cathode chamber to the anode chamber, leading to the low D0 value of the dynamic membrane. Power production of DM-MFCs was further optimized by increasing the NaCl concentration in the influent and the electrode area. The results show that DM-MFCs are feasible and suitable for scaling-up because of their sleeve-shaped configuration. These results indicate that dynamic membranes can be used to increase power production in MFCs relative to traditional separators and DM-MFCs are promising tools for practical applications.

The vacuum membrane distillation (VMD) is a promising technology for lots of applications. To solve the membrane fouling and wetting problems, in this paper, a novel ZnO nanorods 1 H,1 H,2 H,2 H-perfluorodecyltriethoxysilane (PDTS) modified poly(vinylidene fluoride) (PVDF) membrane with a micro/nanoscale hierarchical structure and a superhydrophobic surface has been prepared and applied to the VMD process for distilling highly salty water, for the first time. Among these, a pyrolysis-adhesion method is created to obtain the ZnO seeds and fasten them on the PVDF substrate firmly. The novel modified membrane shows a stable superhydrophobic surface with a water contact angle of 152°, easy cleaning property, excellent thermal and mechanical stability, because of the Cassie's state caused by pocketing much air in the hydrophobized ZnO nanorods, the low surface energy of PDTS coating, and the strong adhesion between ZnO nanorods and PVDF membrane, which has built an ideal structure for VMD application. After 8 h VMD of 200 g L

A spring-like Ti@TiO2 nanowire array wire has been introduced into a stretchable fiber-shaped dye-sensitized solar cell (FDSSC) as a photoanode to achieve high flexibility and elasticity in this paper. Given the TiO2 layer, which was prepared by a hydrothermal reaction in the optimized NaOH concentration of 2.5 mol L−1, with a 1D structure and high adhesion between the TiO2 nanowire array and the Ti wire substrate, the novel FDSSC still possesses photoelectric conversion efficiency retention rates of approximately 97.00% and 95.95% after bending to a radius of 1.0 cm and stretching to 100% strain, respectively. EIS result shows the degradation mechanism of the FDSSC photoelectric performance: the bending test leads to more terrible electron combination; the stretching operation increases the internal resistance and charge-transfer resistance at the counter electrode. Moreover, it's worth noting that, this is the first time to show a 100%-stretching degree in the FDSSC research field so far.

The electrodeposition technique for preparing direct methanol fuel cell electrodes has been developed to increase the Pt utilization and lower the Pt loading. The performance of the Pt/C electrode for methanol oxidation reaction (MOR) was optimized by adjusting the electrodeposition parameters such as applied electrical signal types, ratios of ton/toff, deposition temperatures, and electrolyte concentrations, systematically. Furthermore, the effects of two kinds of additives, i.e. polyethylene glycol (PEG) and sodium dodecyl sulfonate (SDS), on the catalytic performance and morphology of Pt catalyst were investigated for MOR by SEM, XRD, cyclic voltammetry and linear sweep voltammetry. The results show that the optimal Pt catalyst has been prepared by the square wave current method with ton/toff of 1 s/5 s at 30 °C in a 1.0 mmol L−1 H2PtCl6 solution with a 10−4 mmol L−1 PEG additive. Moreover, the effect of the additive type and amount on the formation mechanism of the Pt crystallite morphology has also been discussed. From the results, introducing additives into the deposition solution in the pulse electrodeposition process is useful for designing and fabricating electrocatalytic electrodes for direct methanol fuel cells.

An amorphous SiO2 (a-SiO2) thin film was developed as an artificial passivation layer to stabilize Li metal anodes during electrochemical reactions. The thin film was prepared using an electron cyclotron resonance–chemical vapor deposition apparatus. The obtained passivation layer has a hierarchical structure, which is composed of lithium silicide, lithiated silicon oxide, and a-SiO2. The thickness of the a-SiO2 passivation layer could be varied by changing the processing time, whereas that of the lithium silicide and lithiated silicon oxide layers was almost constant. During cycling, the surface of the a-SiO2 passivation layer is converted into lithium silicate (Li4SiO4), and the portion of Li4SiO4 depends on the thickness of a-SiO2. A minimum overpotential of 21.7 mV was observed at the Li metal electrode at a current density of 3 mA cm–2 with flat voltage profiles, when an a-SiO2 passivation layer of 92.5 nm was used. The Li metal with this optimized thin passivation layer also showed the lowest charge...

To promote development of the unitized regenerative fuel cell, a new energy conversion-storage device, it is essential to look for a bifunctional catalyst with high efficiency and catalytic properties for oxygen evolution and reduction reactions. Herein, a novel PtRuIr electrocatalyst has been synthesized by a pulse electrodeposition method with selectively electrodepositing Ir on PtRu nanoclusters. The prepared catalysts were characterized by electrochemical analysis, scanning electron microscopy and energy dispersive spectrometer. The experimental results show that the PtRuIr catalyst with 10 mol% of Ir exhibits significantly higher oxygen evolution and reduction currents compared to the PtRu and the PtRuIr catalysts with other contents of Ir, which is also supported by the electrochemical impedance data. In addition, a single water electrolysis cell and a H2/O2 fuel cell were performed simultaneously to evaluate the oxygen evolution and reduction performances, respectively, of the novel catalyst. The optimized catalyst with 90 mol% PtRu and 10 mol% Ir shows higher oxygen evolution reactivity current density and higher round-trip efficiency in the water electrolysis single cell, and in the meantime, it also exhibits higher oxygen reduction current density and higher power density in the fuel cell, compared to those of the PtRu catalyst.

With the rapid growth of wearable electronics, the development of wearable fuel cells as a smart power source is receiving ever more attention due to their high energy conversion efficiency, modest operating temperature, and ease of handling. To address the most notable limiting factor, the rigid electrodes, of fuel cells, herein, a eutectic gallium-indium liquid metal with excellent deformability and redox ability has been employed to wearable and rechargeable fuel cells with high performance. Thanks to the optimized Ga/In ratio, which is achieved by balancing the anticorrosion and electrochemical activity of the liquid metal anode, the power density of the fuel cell is as high as 72.8 mW cm−2; to our knowledge, this is the highest power density among existing wearable liquid fuel cells at room temperature. Due to the stable redox properties of liquid metal, the fuel cell was stably cycled for 96 h at 2 mA cm−2 as a rechargeable metal-air battery. Meanwhile, running in feed mode to maintain the proportion of Ga in the anode, the fuel cell and the rechargeable liquid metal fuel cell exhibited stable discharging and cycling performances, respectively, and delivered exemplary performances under various flexibility and stretchability measurements. Based on the fluent and renewable liquid metal anode, this novel high-performance wearable liquid fuel cell shows great promise as a shape-variable energy supply for bionic soft robots and wearable devices.

Citrate-capped magnetites (cit-Fe3O4) are electrostatically conjugated with 3-aminopropyl trimethoxysilane (APS), forming APS-complexed Fe3O4 (A-Fe3O4). Atmospheric calcination induces the direct conversion of A-Fe3O4 into silica-coated Fe2O3 (Fe2O3@SiO2) while preserving its nanoscale dimension (∼15 nm). One-pot chemical etching of the Fe2O3@SiO2 leads to iron oxide particles (Fe2O3) with internal nanocavities, so called nanoporous Fe2O3. After 200 cycles at the current density of 100 mA g−1, the nanoporous Fe2O3 delivers a high reversible capacity of ∼700 mAh g−1 without distinct capacity fading. The excellent cycling stability of the nanoporous Fe2O3 is attributed to the superior buffering effect contributed by its nanoscale dimension and multiple internal nanocavities inside particles, which significantly retard the pulverization process of iron oxide particles. The facile one-pot synthesis of the nanoporous Fe2O3 is an effective, inexpensive route in designing high-performance electrode materials for sustainable energy conversion and storage applications.

To lower methanol crossover and volume swelling degree, and to improve proton conductivity, a simple hot-mould-modifying method has been introduced to modify Nafion membrane for the direct methanol fuel cell application. To evaluate effect of the modification on properties of the Nafion membrane and fuel cell performance, a series of measurements of membranes and fuel cells have been carried out. The results show that, compared with the normal membrane, the modified Nafion membrane with regular spindle-type groove array possesses higher proton conductivity and methanol diffusion resistance, and 31.9% better dimensional stability, owing to its larger electrical double-layer capacitance come from the higher contact area between electron-electrode and ion electrolyte, and its more compact internal structure. And also, the direct methanol fuel cell based on the modified Nafion membrane shows 13.3% higher discharge power density and better long-time running performance than the normal one. Furthermore, this hot-mould-modifying method could be introduced into doping/coating-modified membranes reported in the current literature to further modify Nafion membranes, because this method is compatible with the current modifications.

To understand the effect mechanisms of long-time running and high operation temperature on performance of the direct methanol fuel cell (DMFC) more clearly and directly, in this paper, a new design of 3-electrode system with a solution-type salt bridge has been developed to distinguish the integral polarization into anodic and cathodic polarizations at various temperatures and explore the attenuation mechanism by in situ monitoring the potential of anode during long-time running process at 80 °C, for the first time. The results indicate that the optimized 3-electrode system consists of a standard calomel electrode (SCE) and a solution-type salt bridge placed in the anode hole filled by 0.5 mol L −1 H 2 SO 4 solution. By utilization of the 3-electrode system, the effect mechanisms of the running temperature and time on electrochemical parameters of the DMFC have been found: (1) The increasing operation temperature improves cathodic performance more significantly than that of anode; (2) the attenuation of fuel cell performance mainly comes from that of anode during the 20-h running test at 80 °C, resulting from the sharp drop of electrochemical active surface area of anode. More important, the new 3-electrode system has simplified the detection equipment and reduced the operating difficulty in a practical application for DMFCs, resulting in its portability.

To provide a possible proposal for the large-scale production of a high performance silicon-based anode material in the lithium battery industry, a Cu 3 Si nanoparticle doped porous-silicon particles was prepared via a simplified chemical vapor deposition (CVD) process and heat treatment for the first time. In this work, the Cu 3 Si doping content was optimized by discharge/charge, transmission electron microscopy and electrochemical impedance spectroscopy tests. The results show that compared with the porous-silicon (PS) particles, the Cu 3 Si doping significantly enhanced the discharge capacity, coulombic efficiency, capacity retention, and high-rate performance of the silicon-based anode. The optimum performance with a discharge capacity of 3036.4 mA h g −1 and a coulombic efficiency of 90.49% at the first cycle (after the first three formation cycles) and a capacity retention of 58.72% after 100 cycles occurred at a Cu 3 Si doping content of 2 wt%. The reasons for this are as follows: the PS particles with a similarly silicon nanorod structure accommodated the volume change to maintain the mechanical stability of the electrode during the cycling process; during the simplified CVD process, the nanostructure of silicon was retained; the high conductivity due to Cu 3 Si doping decreased the formation resistance of the solid-electrolyte interphase (SEI) film and enhanced the diffusion coefficient of Li + inside the silicon-based material; both fewer Cu 3 Si doping and aggregation particles resulting from excessive Cu 3 Si doping yielded insufficient electrical conductivity and decreased the formation resistance of the SEI film for the silicon-based material.

To realize gradient activation effect and recover catalytic activity of catalyst in a short time, a gradient activation method has firstly been proposed for enhancing discharge performance and perfecting activation mechanism of the direct methanol fuel cell (DMFC). This method includes four steps, i.e. proton activation, activity recovery activation, H2-O2 mode activation and forced discharging activation. The results prove that the proposed method has gradually realized replenishment of water and protons, recovery of catalytic activity of catalyst, establishment of transfer channels for electrons, protons, and oxygen, and optimization of anode catalyst layer for methanol transfer in turn. Along with the novel activation process going on, the DMFC discharge performance has been improved, step by step, to more than 1.9 times higher than that of the original one within 7.5 h. This method provides a practicable activation way for the real application of single DMFCs and stacks.

Lithium-sulfur battery has become one of the most promising candidates for next generation batteries, and it is still restricted due to the low sulfur conductivity, large volume expansion and severe polysulfide shuttling. Herein, we present a novel hybrid electrode with a ternary nanomaterial based on sulfur-impregnated multiwalled carbon nanotubes filled with ordered tin-monoxide nanoparticles (MWCNT-SnO/S). Using a dry plasma reduction method, a mechanically robust material is prepared as a cathode host material for lithium-sulfur batteries. The MWCNT-SnO/S electrode exhibits high conductivity, good ability to capture polysulfides, and small volume change during a repeated charge–discharge process. In situ transmission electron microscopy and ultraviolet–visible absorption results indicate that the MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution into the electrolyte. Furthermore, the ordered SnO nanoparticles in the MWCNTs facilitate fast ion/electron transfer during the redox reactions by acting as connective links between the walls of the MWCNTs. The MWCNT-SnO/S cathode with a high sulfur content of 70 wt.% exhibits an initial discharge capacity of 1,682.4 mAh·g–1 at 167.5 mA·g–1 (0.1 C rate) and retains a capacity of 530.1 mAh·g–1 at 0.5 C after 1,000 cycles with nearly 100% Coulombic efficiency. Furthermore, the electrode exhibits the high capacity even at a high current rate of 20 C.