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The treatment of high salt organic sewage is considered to be a high energy consumption process, and it is difficult to degrade organic matter and separate salt and water simultaneously. In this study, a gradient structure titanium oxide nanowire film is developed, which can realize the thorough treatment of sewage under sunlight. Among the film, part TiO

Generating heterophase structures in nanomaterials, e.g., heterophase metal nanocrystals, is an effective way to tune their physicochemical properties because of their high-energy nature and unique electronic environment of the generated interfaces. However, the direct synthesis of heterophase metal nanocrystals remains a great challenge due to their unstable nature. Herein, we report the in situ and direct synthesis of heterophase Ni nanocrystals on graphene. The heterostructure of face-centered cubic (fcc) and hexagonal close-packed (hcp) phase was generated via the epitaxial growth of hcp Ni and the partial transformation of fcc Ni and stabilized by the anchoring effect of graphene toward fcc Ni nanocrystal and the preferential adsorption of surfactant polyethylenimine (PEI) toward epitaxial hcp Ni. Comparing with the fcc Ni nanocrystals grown on graphene, the heterophase (fcc/hcp) Ni nanocrystals in situ grown on graphene showed a greatly improved catalytic activity and reusability in 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP). The measured apparent rate constant and the activity parameter were 2.958 min−1 and 102 min−1·mg−1, respectively, higher than that of the best reported non-noble metal catalysts and most noble metal catalysts. The control experiments and density functional theory calculations reveal that the interface of the fcc and hcp phases enhances the adsorption of substrate 4-NP and thus facilitates the reaction kinetics. This work proves the novel idea for the rational design of heterophase metal nanocrystals by employing the synergistic effect of surfactant and support, and also the potential of creating the heterostructure for enhancing their catalytic reactivity.

Flexible supercapacitors (SCs) have become a popular research topic due to their extra-long service life, foldability, and wearability. Nevertheless, their low energy density restricts their applications. Here, we synthesized phosphorus-doped bimetallic sulfides embedded in hetero-atom-doped (N, S, and P) carbon shells (P-ZCS/HC) using a simple approach to create high-performance flexible electrodes. The three-dimensional architecture made by interlaced nanosheets was preserved, and raised nanoparticles appeared on the rough surface during the annealing operation, increasing the specific surface area and potential exposure to the electrolyte. It is noteworthy that the optimal P-ZCS/HC electrode possessed a remarkable capacity of 1080 C g−1 at 1 A g−1 along with superb cycling stability. These extraordinary properties were primarily caused by plentiful redox reactions, enhanced conductivity, and synergic effects of the P-doped metal sulfides and heteroatom-doped carbon shells. Density functional theory simulations confirmed the good function of the P-doped electrodes and their ability to boost conductivity, improve reactive dynamics, and promote OH− adsorption. Notably, the assembled all-solid-state hybrid SC exhibited a maximum energy density of 62.9 W h kg−1 and a power density of 16 kW kg−1, while being able to maintain 92.0% of its initial capacity after 10,000 cycles. This systematic report provides new insight into the design and synthesis of electrodes with complex components and outstanding structures for the flexible energy field.

As a novel energy harvesting method, generating electricity from the interaction of liquid-solid interface has attracted growing interest. Although several functional materials have been carried out to improve the performance of the flow-induced hydrovoltaic generators, there are few reports on influencing the droplet flow behavior to excavate its electricity generation by governing the device structure. Here, the output performance of the graphene microfluidic channel (GMC) structure is ∼13 times higher than that of the flat-open space graphene morphology. The strong slip flow and high surface charge density near the graphene-droplet interface originate from the GMC structure, which produces an effective liquid-solid interaction and rapid relative movement of the droplet. Additionally, based on the GMC structure a self-powered pressure sensor is designed. The droplet motion is regulated by external forces to generate specific voltages, which provide a new approach for the development of wearable self-powered electronics.

Dental implants are in direct contact with living tissue, therefore, biological performance as well as mechanical properties and tribological behavior of implant materials are important and must be systematically investigated. In our study, 3Y–ZrO2 was modified with different concentrations of bioactive, biocompatible graphene oxide (GO). The 3Y–ZrO2/GO composites were fabricated by hot-press sintering. Compared to raw 3Y–ZrO2, addition of GO sharply increased bending strength and fracture toughness, representing an increase of 200% and 41%, respectively. Crack deflection, crack bridging, and GO pull-out were main toughening mechanisms, associated with the formation of a C–O–Zr bond. The addition of GO reduced coefficient of friction and wear rate and lowered surface roughness of 3Y–ZrO2, mainly owing to self-lubricating properties of the composites. In addition, thin film of hydroxyl groups (OH-) on the surface of composites improved wetting properties, as indicated by low contact angle. GO did not cause any obvious signs of cytotoxicity and promoted proliferation, growth, and adhesion of cells. Fully elongated cell morphology was observed on composites. Overall, 3Y–ZrO2/GO composite ceramic with 0.15 wt% GO is promising biomaterial for dental implant applications.

In order to expand the family and improve the bioactivity of oral implant ceramics, the phase structures, mechanical and wetting properties of the hot-pressed yttria-zirconia/multilayer graphene oxide composite (3Y-ZrO2/GO) ceramics were investigated. GO was uniformly distributed in 3Y-ZrO2 powders, forming the C–O–Zr bond during the sintering process. In comparison to raw 3Y-ZrO2 ceramics, the flexural strength and fracture toughness improved up to 200% (1489.96 ± 35.71 MPa) in ZG3 (with 0.15 wt% GO) and 40.9% (8.95 ± 0.59 MPa m1/2) in ZG2 (with 0.1 wt% GO), respectively, while the relative density and Vickers hardness increased slightly. The toughening mechanisms included crack deflection, crack bridging, and GO put-out. Meanwhile, the composite ceramics were transformed into a more hydrophilic direction and indicated a good wetting property. In consideration of mechanical and wetting properties, the ZG3 would be a favorable alternative to the yttria-zirconia ceramic (Y-TZP) in dental implant applications. The results are expected to serve as a technical guidance for the fabrication and evaluation of dental implants.

Lithium–oxygen (Li–O2) batteries are outstanding as next-generation energy-storage devices because of their extremely high theoretical specific energy density. However, their practical application ...

Rechargeable Li–air (O2) batteries have attracted a great deal of attention because of their high theoretical energy density and been regarded as a promising next-generation energy storage technolo...

As a promising alternative to lithium-ion batteries (LIBs), the state-of-art potassium-ion batteries (PIBs) are attracting increasing attentions owing to the abundance and low cost of potassium. However, development of practical electrode materials for PIBs is still in its early stage and the related mechanisms are still unclear. In this work, hierarchically porous carbon supported Sn4P3@C composite prepared through a low temperature solvothermal method is firstly reported as anode material for PIBs. The electrode delivers a high discharge capacity of 473.3 mAh g−1 at 50 mA g−1 and superior rate capability of 183.6 mAh g−1 at 2.0 A g−1, surpassing most of the reported anode materials. Besides, the Sn4P3@C electrode can maintain a high reversible capacity of 181.5 mAh g−1 after 800 cycles at a high current density of 500 mA g−1. Moreover, in-depth characterizations such as GITT (Galvanostatic Intermittent Titration Technique), ex-situ XRD/HRTEM and consecutive CV (Cyclic Voltammetry) measurements are conducted to reveal the mechanisms involved in the potassiation/de-potassiation repeats.

Two-dimensional materials have been extensively investigated in the fields of electrochemical sensors, field-effect transistors, and other electronic devices due to their large surface areas, high ...

Tin chalcogenides are regarded as promising anode materials for potassium ion batteries (PIBs) due to their considerable specific capacity. However, the severe volume effect, limited electronic conductivity, and the shuttle effect of the potassiation product restrict the application prospect. Herein, based on the metal evaporation reaction, a facile structural engineering strategy for yolk-shell SnSe encapsulated in carbon shell (SnSe@C) is proposed. The internal void can accommodate the volume change of the SnSe core and the carbon shell can enhance the electronic conductivity. Combining qualitative and quantitative electrochemical analyses, the distinguished electrochemical performance of SnSe@C anode is attributed to the contribution of enhanced capacitive behavior. Additionally, first-principles calculations elucidate that the heteroatomic doped carbon exhibits a preferable affinity toward potassium ions and the potassiation product K

Featuring high electrical conductivity and electrochemical activity, transition metal sulfides are promising materials for the positive electrode of hybrid supercapacitors. However, considering their poor cycling life and rate performance, critical challenges remain. In this contribution, we describe hollow NiS2/CoS2@C composites obtained by stepwise etching, annealing, and sulfuration of ZIF-67. Specifically, NiS2/CoS2 particles were dispersed on N/S co-doped carbon nanocages and found to exhibit outstanding stability and rate performance. The unique nanocage structure of N/S co-doped carbon and heterogeneous interfaces of NiS2 and CoS2 can promote both ion transport and electron transfer, enriching the active site for enhanced reactivity. The resulting NiS2/CoS2@C nanocage composites in fact showed considerable electrochemical performance, with a specific capacity of 1373 C g-1 at 1 A g-1. When combined with reduced graphene oxide (RGO)-based negative electrode, the assembled hybrid supercapacitor registered an energy density of 63.3 Wh kg-1 at a power density of 800 W kg-1, retaining exceeding 98% of the initial capacity even after 13,000 cycles.

Owing to increased specific surface area and catalytic ‘hot spots’, nanoporous nickel film (NPNF) have presented an efficiency performance for hydrazine electrocatalysis. NPNF samples were fabricated by dealloying Ni–Al precursor alloys synthesized by magnetron co-sputtering on Ni foils. It was observed that both continuous ligaments and pore channels of the NPNF electrodes with a size of about 38 nm, enabled the electrode to electrocatalyze the hydrazine decomposition with high efficiency at a potential of 0.32 V vs. RHE. We also explored the molecular mechanism of the electrocatalytic decomposition of hydrazine on Ni (111) surface by DFT computations, ideally corresponding to our experimental results. Based on the observations, nanoporous Ni have overthrown the cognition of monometallic Ni for inefficient hydrazine decomposition, improving significantly the technology for hydrogen generation and energy storage.

Rechargeable lithium–oxygen (Li–O2) batteries (LOBs) with extremely high theoretical energy density have been regarded as a promising next-generation energy storage technology. However, the limited...

High efficient adsorption of radioiodine in nuclear waste has attracted extensive attentions all over the world. In this work, we fabricated sulfur and nitrogen co-doped graphene aerogels (SN-GA) through one-step hydrothermal method, and investigated its iodine adsorption behavior including adsorption kinetics and isotherms in water. Our results reveal that SN-GA exhibits a 3D porous architecture with thiophene-S, oxidized-S, pyridine-N, pyrrole-N and graphite-N co-doped into the sp2 carbon frameworks. The adsorption experiment showed SN-GA has a maximum iodine adsorption capacity of 999 mg g−1 determined by Langmuir isotherm, and the adsorption process could be better described by the pseudo-second-order model.

Aqueous rechargeable Li-ion hybrid supercapacitors are attracting increasing attention owing to their intrinsic advantages compared with nonaqueous counterpart and the combination of high energy and power densities in an individual device. However, the lack of satisfactory battery-type cathode materials with fast lithium ion storage limits the overall performance. Herein, we report a composite structure by incorporating LiMn2O4 nanoparticles in graphene/carbon nanotubes network (LiMn2O4@CNTs@graphene) as superior cathode for aqueous hybrid capacitors. LiMn2O4@CNTs@graphene nanocomposite shows high capacitance with ultrafast lithium diffusion, which is mainly boosted by pseudocapacitive behavior, making it a potential candidate for hybrid supercapacitors. Hybrid devices assembled with LiMn2O4@CNTs@graphene cathode and N/S co-doped activated carbon anode exhibit an optimized overall performance with a high energy density of 62.77 Wh kg−1 and high power density of 2967.96 W kg−1 as well as good cycling performance with the capacitance retention of 90.8% after 5000 cycles.

Potassium- (PIBs) and sodium-ion batteries (SIBs) are emerging as promising alternatives to lithium-ion batteries owing to the low cost and abundance of K and Na resources. However, the large radius of K+ and Na+ lead to sluggish kinetics and relatively large volume variations. Herein, a surface-confined strategy is developed to restrain SnS2 in self-generated hierarchically porous carbon networks with an in situ reduced graphene oxide (rGO) shell (SnS2 @C@rGO). The as-prepared SnS2 @C@rGO electrode delivers high reversible capacity (721.9 mAh g-1 at 0.05 A g-1 ) and superior rate capability (397.4 mAh g-1 at 2.0 A g-1 ) as the anode material of SIB. Furthermore, a reversible capacity of 499.4 mAh g-1 (0.05 A g-1 ) and a cycling stability with 298.1 mAh g-1 after 500 cycles at a current density of 0.5 A g-1 were achieved in PIBs, surpassing most of the reported non-carbonaceous anode materials. Additionally, the electrochemical reactions between SnS2 and K+ were investigated and elucidated.

Layered Ti3C2Tx powders have been experimentally proved to hold high adsorption activity, while it is useless to be an efficient demulsifier. Pure chitosan powders with excellent adsorption are easy to dissolve in acidic solution, so it is difficult to break of acid oil-in-water emulsions. In order to expand the application fields in breaking up the emulsified oily waste acid water, chitosan loaded Ti3C2Tx powders have been successfully fabricated by simple means, which can be used to strong acidic emulsions and improve the use ratio of acid water. Chitosan loaded Ti3C2Tx powders possess higher specific surface area than that of Ti3C2Tx powders, so these powders possess more reactive activation. In addition, chitosan loaded Ti3C2Tx powders would be applied to high-temperature condition, which possess extensive temperature limit (

Hollow nanostructured materials present a class of promising electrode materials for energy storage and conversion. Herein, 3D hollow nitrogen-doped carbon shells decorated with well-defined cobalt sulfide nanoparticles (Co9S8 /HNCS) have been constructed for superior lithium and sodium storage. Two steps are involved in the designed preparation procedure. First, hollow intermediates with preserved cobalt components are controllably fabricated by simultaneously dissociating cobalt containing zeolitic-imidazolate-frameworks-67 (ZIF-67), and polymerizing dopamine in a Tris–HCl solution (pH = 8.5). The polydopamine (PDA) wrapped intermediates inherits the polyhedral structure of the ZIF-67 crystals. In the second step, the final Co9S8 /HNCS composite is obtained via a combined carbonization and sulfurization treatment of the intermediates, allowing the formation of hollow polyhedrons of nitrogen-doped carbon shells (900±100 nm) derived from PDA and the encapsulation of highly uniform cobalt sulfide nanoparticles (11±2 nm). This configuration is believed to not only shorten the lithium or sodium ion diffusion distance and accommodate volume change during lithium or sodium ion insertion/extraction, but also to enhance the overall electrical conductivity and the number of active sites. As a result, the Co9S8 /HNCS composite exhibits an impressive reversible capacity of 755 mA h g-1 at 500 mA g-1 after 200 cycles for lithium ion storage, and capacities of 327 mA h g-1 at 500 mA g-1 after 200 cycles and 224 mA h g-1 at 1000 mA g-1 after 300 cycles for sodium ion storage. Essential factors especially the structural stability during cycling have been identified, and the discharge/charge mechanism is discussed.

Dendritic growth of the metallic lithium anode cannot be fully avoided for prolonged cycling due to the inherent thermodynamic and kinetic tendency, which causes serious safety issues. Here, we strategically control the lithium metal growth direction by designing a three-dimensional porous host with lithiophilic-lithiophobic characterized ligaments. Therefore, lithium metal can only nucleate on the lithiophilic back surface and grow toward the direction away from the separator. Such ‘backside-growth’ can ensure safe battery operation even when lithium dendrites exist. For a proof-of-concept study, highly lithiophilic gold layer is sputtered on backside surface of each copper foam ligament. During lithium plating, lithium nucleates on the lithiophilic backside and keeps growing conformably from the existing nuclei towards the opposite direction to the separator, and eventually forms a lithium-metal layer with highly compacted self-aligned columnar structure. The novel approach controls lithium deposition in two aspects simultaneously: growth direction and morphology. Notably, the featured surface dendrite-free anode exhibits ultra-long-term stable cycling with a high Coulombic efficiency (e.g., 95.0% after 300 cycles, 0.5 mA cm−2, 1 mA h cm−2). This work may not only pave ways for building ultimate safe lithium batteries but also conceptually provides new opportunities for other metal anodes.

LixMnO2 nanowires with controllable morphology and excellent electrochemical performance are synthesized by a hydrothermal method with tunable lithium contents. Both double layer capacitive process and diffusion-controlled Faradaic process play roles in the charging-discharging process. Aqueous Li-ion hybrid supercapacitors are assembled using LixMnO2 nanowires as the positive electrode and activated carbon as the negative electrode. The hybrid devices deliver high energy density of 88.56 Wh kg−1 and 25.2 Wh kg−1 at the high power density of 151.8 W kg−1 and 2155.8 W kg−1, respectively. The device also shows superb cycling life with capacitance retention of 95.2% after 10,000 cycles and 85.2% after 20,000 cycles.

Hard carbon has attracted enormous attentions as electrode materials for various energy storage devices owing to its low cost, abundant sources and high theoretical capacitances/capacities. However, it still suffers poor electrical conductivity and unsatisfying rate performance. Herein, N/S co-doped ultrathin carbon nanosheet is reported as high performance electrode material for both supercapacitors and sodium-ion batteries. The symmetric supercapcitors assembled with the as-synthesized materials (1.0 M Na2SO4 as electrolyte) deliver a high energy density of 24.5 Wh kg−1 at a power density of 500 W kg−1 within a wide voltage range of 0–2.0 V. When being served as anode for sodium-ion batteries, the electrode exhibits a high reversible capacity (371.2 mAh g−1 @ 0.1 A g−1) and superior rate capability (180.9 mAh g−1 @ 10.0 A g−1). Besides, the as-fabricated electrodes display stable cycling performance in both energy storage systems. Subsequent mechanism studies further shed light on the excellent electrochemical performance.

Designing excellent electrode materials by establishing superb architectures provides a feasible way to boost the electrochemical properties of supercapacitors (SCs). Herein, a self-supported bimetallic Ni–Fe phosphide (Ni–Fe–P) electrode with a newfangled and multidimensional construction was synthesized by a two-step process. This electrode consists of connective nanosheets which combined numerous interlinked nanoparticles with well-distributed mesopores. By investigating the effects of phosphating temperatures, an optimal phosphide electrode with well-distributed pores throughout the interlaced nanosheets has been obtained. Due to this sophisticated porous structure and the mechanical stability enhanced by the direct growth on binderless Ni foam, the Ni–Fe–P electrode exhibits outstanding electrochemical performance. Density functional theory (DFT) calculations are also performed to demonstrate the increased electrical conductivity and reactivity after the introduction of Fe atoms and phosphorization. Impressively, the fabricated Ni–Fe–P//reduced graphene oxide solid-state SC device delivers an outstanding energy density of 50.2 W h kg−1 at a power density of 800 W kg−1, and remarkable cycle performance (91.5% retention rate after 10 000 cycles). This comprehensive work not only displays a new perspective of the phosphating mechanism at different temperatures but also suggests a versatile approach for engineering promising electrode materials for advanced SCs.

Hollow Zn0.76Co0.24S@N-doped carbon (HZCS@NC) electrode with hierarchical pores structure synthesized by a continuous ingenious method is presented in response of the demand of high-performance supercapacitors. The formation mechanism of the hollow structure, in which the Zn0.76Co0.24S nanoparticles were embedded in a nitrogen-doped carbon layer, was analyzed in this work. This electrode exhibits an excellent specific capacity of 937 C g−1 at 1 A g−1 and a satisfying capacity retention rate of about 112% after 40 000 cycles at a rate of 5 A g−1. Such preeminent performance is realized via (1) the short electrolyte diffusion length caused by the hollow structure, (2) the high electrochemical activities provide by the bimetallic sulfide and heteroatom doping, (3) the efficient combination of faradaic and electrical double layer materials, and (4) the conductive network with multiple holes. The evaluation of electrochemical performance of the assembled HZCS@NC//RGO hybrid supercapacitor (HSC) was also done. Impressively, the HSC gives a satisfactory energy density of 55.47 W h kg−1, a maximum power density of 16.55 kW kg−1, and an ultra-long (100 000) cycling life (108.9% retention of the initial capacity). This study presents a novel strategy for engineering stable poly-porous multicomponent hollow structures for the fabrication of prospective energy storage devices.

As a promising material, Ti3C2Tx has received much attention in recent years for brilliant performances in conductivity and lubricity. In order to modify the property of Ti3C2Tx, MoS2 intercalated Ti3C2Tx (Ti3C2Tx/MoS2) powders are made from hydrothermal reaction, which can prohibit oxidization for MoS2 particles. Ni-P-Ti3C2Tx/MoS2 and Ni-P-Ti3C2Tx composite coatings are prepared by electroplating technique with addition of Ti3C2Tx/MoS2 and Ti3C2Tx particles, respectively. Compared to Ni-P composite coatings, Ni-P-Ti3C2Tx/MoS2 and Ni-P-Ti3C2Tx composite coatings show a decrease in coefficient of friction (COF). The wear loss of Ni-P-Ti3C2Tx/MoS2 composite coating is only about 0.10 mg after 5 min, under dry-grinding with the load of 2 N and circle radius of 1 cm. It is worth to mention that the microhardness of the two composite coatings gets improved much, which can be up to 1200 kg mm−2. Even though the surface roughness of Ni-P-Ti3C2Tx/MoS2 composite coating increases, the surface of the composite coating is converted from hydrophilic to hydrophobic.

3D porous sulfur and nitrogen co-doped graphene aerogel has been fabricated by a facile one-pot process. Both experimental and theoretical studies have demonstrated that sulfur and nitrogen co-doping could synergistically enhance the catalytic performance for activating peroxydisulfate (PDS) compared to the original and N doped graphene aerogels. The ratio of sulfur/nitrogen in the aerogel can be controlled by regulating the additions of thiourea and urea sources, and the aerogel with the S/N ratio of about 1:2.5 shows a better catalytic effect due to more significant changes in the electrostatic potential and the surface charge distribution, as revealed by the theoretical simulations. The radical quenching tests indicated that both SO4·- and ·OH radicals could be formed in the SN-rGO aerogel + PDS system and contribute most to RhB degradation.

Carbon nanofibers yarns (CNY) have been prepared by carbonizing twisted electrospun PAN nanofibers, which can be used as the electrode of fiber-shaped all-solid-state supercapacitor after depositing conductive polymer of polypyrrole (PPy) and reduced graphene oxide (rGO) on their surface to form a core-shell structure (CNY@PPy@rGO). The flexible and binder-free fiber supercapacitors with PVA/H3PO4 gel electrolyte have a high specific capacitance (92.57 F/g, 80.46 F/cm3, 836.87 mF/cm2, and 111.46 mF/cm of CM, CV, CA, and CL, respectively, at the scan rate of 2 mV/s) thanks to the core-shell structure and synergistic effects of three conponents. It also shows high cycling performance with 86% capacitance retention after 10000 cycles with excellent flexibility and stability at different bending angles.

Sulfur and nitrogen co-doped graphene aerogel with Janus wettability of superhydrophobic/superhydrophilic was prepared with hydrothermal reduction combined with electrostatic spraying method. The upper surface exhibited an interconnected and porous 3D network with superhydrophobic property (water contact angle > 150°), while the under surface displayed a continuous membrane structure possessing rich wrinkles with superhydrophilicity (water contact angle

Selective noxious gas sensing at low temperature is very important in some industrial applications. Here, we demonstrate that the reduced graphene oxide (RGO) wrapped Au@ZnO core-shell composite can be fabricated in wafer-level and used as the key sensor materials for triethylamine sensing with a high response of 12.2% for 5 ppm of TEA gas at a low temperature (50 °C). The sensitivity of RGO/Au/ZnO sensor to TEA gas achieved almost 6 times higher than that of ethanol and acetone, 5 times that of methanol and isopropanol, and 3 times that of ammonia. The selective sensing properties are largely attributed to the synergistic effect of the core-shell structure and the ZnO/RGO heterojunctions. This work provides a significant strategy for TEA gas sensor selective sensing arrays application at low temperatures.

Three-dimensional (3D) porous N-doped carbon nanoflake structures decorated with in situ formed Ag nanoparticles (Ag-NCNS) have been synthesized for the first time by a feasible salt-assisted polym...

Low ionic conductivity and poor interfacial compatibility between lithium electrodes and Li7P3S11 sulfide solid electrolytes are the greatest challenges for all-solid state lithium-sulfur batteries. Herein, we introduce a hybrid solid electrolyte with Li7P3S11 being wrapped with polyethylene oxide-LiClO4 (PEO-LiClO4). As served as conductive bridge between Li7P3S11 particles, PEO-LiClO4 would provide Li+ transition paths between Li7P3S11 particles, thus successfully improve its ionic conductivity. Moreover, the polymer layer of PEO-LiClO4 can isolate lithium metal and Li7P3S11 solid electrolyte, suppressing the reaction between lithium electrode and Li7P3S11 electrolyte. Therefore, hybrid solid electrolyte Li7P3S11-PEO-LiClO4 shows excellent interfacial compatibility with lithium foil. Lithium-sulfur battery with the hybrid electrolyte Li7P3S11-PEO-LiClO4 exhibits much improved electrochemical performance with better cycling stability and higher Coulombic efficiency.

Designing efficient and robust nonprecious metal-based electrocatalysts for overall water electrolysis, which is mainly limited by the oxygen evolution reaction (OER), for hydrogen production remains a major challenge for the hydrogen economy. In this work, a bimetallic NiFeP catalyst is coated on nickel phosphide rods grown on nickel foam (NiFeP@NiP@NF). This self-supported and interfacially connected electrode structure is favorable for mass transfer and reducing electrical resistance during electrocatalysis. The preparation of NiFeP@NiP@NF is optimized in terms of (i) the coprecipitation time of the NiFe Prussian blue analogue layer that serves as phosphides precursor and (ii) the phosphidation temperature. The optimized sample exhibits excellent OER performance delivering current densities of 10 and 100 mA cm-2 at low overpotentials of 227 and 252 mV in 1.0 M KOH, respectively, and maintaining 10 mA cm-2 for more than 120 h without obvious degradation. Moreover, it can also be operated as a hydrogen evolution electrocatalyst, requiring an overpotential of 105 mV at 10 mA cm-2 in the same medium. Thus, the as-prepared material was tentatively utilized as a bifunctional electrocatalyst in a symmetric electrolyzer, requiring a voltage bias of 1.57 V to afford 10 mA cm-2 in 1.0 M KOH, while exhibiting outstanding stability.

This paper aimed to improve the adhesion strength of the polypyrrole–zinc oxide/tungsten substrate (PPy–ZnO/W) system. Groove-like textures with different depths on the surface of tungsten substrates were prepared using a laser treatment, and then PPy–ZnO nanocomposites were fabricated on substrates with or without textures via electrochemical polymerization. The effects of textures on the morphology, microstructure, mechanical properties, and electrical conductivity were systematically analyzed. Pull-out tests were employed to assess the adhesion strength of different coated samples. The results indicated that the adhesion strength of the PPy-ZnO coating can be significantly improved by applying a texture process to the W substrates. The coating deposited on the textured substrate with a depth of 5.4 μm had the strongest adhesion strength, reaching 4.14 ± 0.25 MPa, which was 75% higher than that of the untextured sample at 2.36 ± 0.25 MPa. This enhancement effect is mainly contributed to by the laser textured surface, which created a larger and mechanical anchoring interface between the coating and substrate, compacted the microstructure of the coating and activated the surface of the substrates.

Porous zinc manganate (ZnMn2O4), which is typically fabricated from the decomposition of its carbonates, promises a high-performance anode material for lithium ion batteries (LIBs). Most of porous ZnMn2O4 in literature presents in sphere morphology. Herein, a unique type of porous ZnMn2O4 hexagons with a side length of about 2 μm and a BET specific surface area of 34.19 m2 g−1, assembled by ca. 100 nm nanoparticles, has been successfully fabricated by a solvothermal reaction with subsequent calcination of the self-assembled catena-poly intermediates. The growth mechanism of the solvothermal products has been systematically investigated by adjusting the stoichiometric ratio of oxalic acid, the type of the salt source and acid additive, and the reaction media, resulting in a wide spectrum of morphologies ranging from hexagon, porous sphere, hourglass to belt. The hexagon precursor was calcined in air to obtain the porous structure, attributed to the spaces between nanoparticle assemblies. When used for lithium-ion storage, the as-prepared porous ZnMn2O4 hexagons-based anode exhibits a reversible capacity of 716 mA h g−1 after 200 cycles at 100 mA g−1, outperforming the pure porous Mn2O3 hexagons and the non-porous ZnMn2O4 hexagons.

Manganese oxides (MnOx) and derivations are considered as one of the most attractive anode materials for lithium-ion batteries (LIBs) due to their earth-abundant, cost-effective and low-toxic specialties. Herein, we report a flower-like composite consisting of internal Fe2O3 nanocrystals and outer hierarchal iron doped K-birnessite type MnOx layers (Fe2O3@Fe doped K-birnessite), which is synthesized by a facile one-pot microwave-assisted heating synthesis (MAHS). The crystalline and morphology evolution of Fe2O3@Fe doped K-birnessite composite are studied by checking the products at various reaction durations, using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning & transmission electron microscopy (SEM & TEM). Key factors affecting the morphology such as reactive temperature and stoichiometric ratio are systematically investigated. When tested for LIBs, the optimized hybrid Fe2O3@Fe doped K-birnessite composite exhibits a high reversible capacity of 758 mA h g−1 at 500 mA g−1 after 200 cycles, outperforming the pure K-birnessite (203 mA h g−1). The excellent electrochemical performance is assigned to the efficient utilization of the merits of the flower-like structure and strong interaction between MnOx and Fe2O3. Further, crucial factors associated with structural stability of Fe2O3@Fe doped K-birnessite composite during cycling are identified.

Lithium–oxygen batteries (LOBs) have attracted increasing interest because of their superior theoretical specific energy. However, the stability of lithium metal anode is one of the obstacles limiting their practical applications. Here, we introduce an artificial Li3PO4 solid electrolyte interphase (SEI) film to protect the lithium anode in LOB with LiI/LiNO3/DMSO (dimethyl sulfoxide) electrolyte. The Li3PO4-protected Li anode exhibits excellent electrochemical stability during the Li stripping/plating process and leads to a relatively uniform and featureless surface in LOB after cycling. Our research demonstrates that superior electrochemical performance can be achieved in the Li–O2 battery with the synergistic combination of the DMSO-based electrolyte, the LiI redox mediator, and the Li3PO4-protected Li anode. The LOB with a Li3PO4-protected Li anode exhibits a prolonged cycling life span of 152 cycles with a fixed capacity of 1000 mA h g–1 at 2 A g–1. The results in this work provide knowledge for the ...

A free-standing sandwich-structured polyamide 6 (PA 6)@GO@PA 6 nanofiltration membrane intercalated by nanoparticles with high water flux was prepared using electrospraying combined with electrospinning method. According to the XRD patterns, the interlayer spacing of the membrane increases with the TiO2 nanoparticle (NP) intercalated. The TiO2 NP intercalated PA 6@GO (120)@ PA 6 nanofiltration membrane shows a pure water flux up to 13.77 L m−2 h−1 bar−1 even under an extremely low external pressure (1.0 bar), which increased by 80.7% than that of PA 6@GO (120)@PA 6 nanofiltration membrane (7.62 L m−2 h−1 bar−1) without nanoparticles intercalated, and maintains high organic dye rejection capabilities (>85% for BF, >92% for MB, >99% for MO, and 99.85% for EB). Besides TiO2, other nanoparticles, such as SiO2 and Si3N4 can also improve the water flux and maintain high rejection rate for MO and MB. Furthermore, TiO2 intercalated PA 6@GO (120)@PA 6 nanofiltration membrane is very stable even under ultrasonication, and shows a high flux for some common solvents (12.32, 4.91, and 1.26 L m−2 h−1 bar−1 for methanol, ethanol, and NMP, respectively).

Methanol gas sensors with excellent performances are in great demand to monitor the industrial manufacture and many household products. We have synthesized Pt-activated SnO2 nanoparticles partly wrapped by reduced graphene oxide (RGO) for high performance methanol gas sensor application. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicated that the platinum element is present in two types, including metal (Pt) and tetravalent metal oxide (PtO2) in the Pt-activated SnO2 clusters. The SnO2 nanoparticles with an average size of about 10 nm are in form of cluster type and there are abundant random wormhole-like pores throughout each cluster. The gas responses of the pristine SnO2 gas sensor, Pt-activated SnO2 gas sensor and the RGO-assisted sensors toward 40 ppm methanol at the relatively low operating temperatures (110 °C) were 7.8, 38.5 and 60.1, respectively. And the sensor exhibited shorter response time with only 6 s. The excellent gas-sensing properties are mainly attributed to the improved electronic interaction and the reduced potential barrier between RGO and Pt/SnO2.

Rechargeable Li-air (O

A flexible and free-standing graphene oxide and nylon 6 (GO@nylon 6) multilayer nanofiltration membrane was prepared by a layer-by-layer assembly process. The combination of electrospinning and electrospraying technique was employed, which can facilely prepare large-area membrane with size of 20 × 30 cm. The mechanical stability of multilayer membrane has enhanced significantly due to the tightly locked structure achieved by nylon 6 nanofibers network. The novel GO@nylon 6–13 multilayer nanofiltration membrane demonstrated a pure water flux up to 11.15 L m−2 h−1 bar−1, while keeping high organic dye rejection rate (>95% for methylene blue, and >99% for methyl orange). The rejections rate of the Na2SO4, NaCl, CuSO4, and Pb(NO3)2 were 56.5%, 27.6%, 36.7%, and 18.9%, respectively. Furthermore, GO@nylon 6–13 multilayer nanofiltration membrane also demonstrated a high flux of some common organic solvents (8.4, 5.3, and 0.8 L m−2 h−1 bar−1 for methanol, ethanol, and NMP, respectively), showing excellent chemical stability for separation process in those solvents.

Two-dimensional materials have been extensively investigated in the fields of electrochemical sensors, field-effect transistors, and other electronic devices due to their large surface areas, high compatibility with device integration, and so on. Conventional electrodes, such as precious metal layers that are deposited on polymer or silicon wafers, have gradually revealed increasing difficulties in adapting to various device structures, especially for two-dimensional materials, which prefer high exposure of surface atoms. Here, we demonstrate a tailorable metal-ceramic (Cu-TiC