Highly Reversible Zn Anodes through a Hydrophobic Interface Formed by Electrolyte Additive.

Hydrogen evolution reaction and dendrite growth seriously break the Zn plating/stripping process at the electrolyte/electrode interface, causing the instability of the Zn anode of aqueous zinc ion batteries. To improve the Zn anode stability and reversibility, we report a new electrolyte additive of aqueous electrolyte with the hydrophobic group. This interfacial hydrophobicity maximises the exclusion of free water from the Zn anode surface, which blocks water erosion and reduces interfacial side reactions. Thus, in an optimal 2 M ZnSO4 electrolyte with 2 g·L-1 Tween-85, the hydrogen evolution reaction and other water-induced undesired reactions can be suppressed, which greatly improves the cycling stability and Coulombic efficiency (CE) of Zn plating/stripping process. The stable cycle time of the Zn//Zn symmetric battery reaches over 1300 h, especially at a high current density and a high areal capacity (more than 650 h at 5 mA·cm-2, 5 mAh·cm-2). The average Coulomb efficiency (CE) of Zn//Ti asymmetric cell achieves 98.11% after 300 cycles. The capacity retention rate of Zn//MnO2 full battery is up to 88.6% after 1000 cycles.

Study on Thermal Effect of Aluminum-Air Battery.

The heat released from an aluminum-air battery has a great effect on its performance and operating life during the discharge process. A theoretical model was proposed to evaluate the resulting thermal effect, and the generated heat was divided into the following sources: anodic aluminum oxidation reaction, cathodic oxygen reduction reaction, heat production against the battery internal resistance, and hydrogen-evolution reaction. Quantitative analysis was conducted on each part, showing that all heat production sources increased with discharge current density. It should be noted that the heat caused by hydrogen evolution accounted for the most, up to 90%. Furthermore, the regulation strategy for inhibiting hydrogen evolution was developed by addition of hybrid additives to the electrolyte, and the hydrogen-evolution rate was greatly reduced by more than 50% as was the generated heat. This research has important guidance for the thermal effect analysis of aluminum-air batteries, together with control of the thermal management process by inhibiting hydrogen evolution, thus promoting their practical application.

Effect of compressive stress on cavitation erosion-corrosion behavior of nickel-aluminum bronze alloy.

The effect of compressive stress on cavitation erosion-corrosion behavior of nickel-aluminum bronze alloy was investigated, and the results showed that the alloy exhibited selective phase corrosion of eutectoid "α + κiii" and its destruction was aggravated with more cavitation mass loss up to 1.74 times of the specimen without stress. It was mainly owing to the enhanced corrosion-induced erosion caused by compressive stress, which led to lattice distortion of the alloy and the resulting accelerated selective phase corrosion with increasing surface roughness, and then intensified the synergistic effect of electrochemical corrosion and mechanical erosion.

Improving Discharge Voltage of Al-Air Batteries by Ga3+ Additives in NaCl-Based Electrolyte.

The application of NaCl-based aluminum-air batteries is limited due to the passivation of the aluminum anode. In an effort to solve this problem, this work studied the influence of different concentrations of Ga3+ additives on the discharge behavior of Al in the NaCl electrolyte. The results of both experiments and theoretical calculations have shown that commercial purity aluminum could be significantly activated by Ga3+. Based on microstructure observations and electrochemical impedance spectroscopy, the influence activation mechanism of Ga3+ on the discharge behavior of commercial purity Al is clarified. The addition of Ga3+ biased the surface charge of aluminum along the activation direction, forming activation sites, and then destroyed the surface passivation film. Due to the formation of a gallium-aluminum amalgam, the Al-air battery had the best discharge characteristics in the electrolyte with 0.2 M Ga3+, and its discharge voltage reached 0.9734 V with a remarkable increase compared with that of NaCl solution (0.4228 V). Therefore, Ga3+ additive is a promising choice for NaCl-based Al-air batteries to improve their discharge voltage.

Development and Challenges of Biphasic Membrane-Less Redox Batteries.

Ion exchange membranes (IEMs) play important roles in energy generation and storage field, such as fuel cell, flow battery, however, a major barrier in the way of large-scale application is the high cost of membranes (e.g., Nafion membranes price generally exceeds USD$ 200 m-2 ). The membrane-less technology is one of the promising approaches to solve the problem and thus has attracted much attention and been explored in a variety of research paths. This review introduces one of the representative membrane-less battery types, Biphasic membrane-less redox batteries that eliminate the IEMs according to the principle of solvent immiscibility and realizes the phase splitting in a thermodynamically stable state. It is systematically classified and summarizes their performances as well as the problems they are suffering from, and then several effective solutions are proposed based on the modification of electrodes and electrolytes. Finally, special attention is given to the challenges and prospects of Biphasic membrane-less redox batteries, which could contribute to the development of membrane-less batteries.

Bimetallic Multi-Level Layered Co-NiOOH/Ni3 S2 @NF Nanosheet for Hydrogen Evolution Reaction in Alkaline Medium.

Development of efficient non-noble metal catalysts for water splitting is of great significance but challenging due to the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline medium. Herein, a bimetallic multi-level layered catalytic electrode composed of Ni3 S2 nanosheets with secondary Co-NiOOH layer of 3D porous and free-standing cathode in alkaline medium is reported. This integrated synergistic catalytic electrode exhibits excellent HER electrocatalytic performance. The resultant Ni0.67 Co0.33 /Ni3 S2 @NF electrode displays the highest HER activity with only overpotentials of 87 and 203 mV to afford current densities of 10 and 100 mA·cm-2 , respectively, and its Tafel slope is 80 mV·dec-1 . The chronopotentiometry operated at high current density of 50 mA·cm-2 shows negligible deterioration, indicating better stability of Ni0.67 Co0.33 /Ni3 S2 @NF electrode than Pt/C (20 wt.%). Such a desirable catalytic performance is attributed to the modification of physical and electronic structure that exposes abundant active sites and improves the intrinsic catalytic activity toward HER, which is also confirmed by electrochemically active surface area and X-ray photoelectron spectroscopy analysis. This work provides a strong support for the rational design of high-performance bimetallic electrodes for industrial water splitting.

Metal Material, Properties and Design Methods of Porous Biomedical Scaffolds for Additive Manufacturing: A Review.

Design an implant similar to the human bone is one of the critical problems in bone tissue engineering. Metal porous scaffolds have good prospects in bone tissue replacement due to their matching elastic modulus, better strength, and biocompatibility. However, traditional processing methods are challenging to fabricate scaffolds with a porous structure, limiting the development of porous scaffolds. With the advancement of additive manufacturing (AM) and computer-aided technologies, the development of porous metal scaffolds also ushers in unprecedented opportunities. In recent years, many new metal materials and innovative design methods are used to fabricate porous scaffolds with excellent mechanical properties and biocompatibility. This article reviews the research progress of porous metal scaffolds, and introduces the AM technologies used in porous metal scaffolds. Then the applications of different metal materials in bone scaffolds are summarized, and the advantages and limitations of various scaffold design methods are discussed. Finally, we look forward to the development prospects of AM in porous metal scaffolds.

Preparation and Thermal Conductivity of Epoxy Resin/Graphene-Fe3O4 Composites.

By modifying the bonding of graphene (GR) and Fe3O4, a stable structure of GR-Fe3O4, namely magnetic GR, was obtained. Under the induction of a magnetic field, it can be orientated in an epoxy resin (EP) matrix, thus preparing EP/GR-Fe3O4 composites. The effects of the content of GR and the degree of orientation on the thermal conductivity of the composites were investigated, and the most suitable Fe3O4 load on GR was obtained. When the mass ratio of GR and Fe3O4 was 2:1, the thermal conductivity could be increased by 54.8% compared with that of pure EP. Meanwhile, EP/GR-Fe3O4 composites had a better thermal stability, dynamic thermomechanical properties, and excellent electrical insulation properties, which can meet the requirements of electronic packaging materials.

[Free sensate intercostal artery perforator flap for hand soft tissue reconstruction].

OBJECTIVE: To investigate the effectiveness of free sensate intercostal artery perforator flap for the hand soft tissue reconstruction. METHODS: Between March 2010 and September 2015, 19 cases of hand soft tissue defect were repaired with free sensate intercostal artery perforator flap, including 16 males and 3 females, aged from 18 to 53 years, with an average of 35.2 years. The defect was located in the dorsum of the hand in 15 cases and in the palm in 4 cases. The causes of injury were traffic accident injury in 8 cases, hot crush injury in 5 cases, strangulation injury in 4 cases, and avulsion injury in 2 cases. All of them were full-thickness skin and soft tissue defects of hand with exposure of phalanges, tendons, blood vessels, and nerves. The size of defect was 10.0 cm×7.0 cm to 17.0 cm×8.0 cm. There were 12 cases of emergency operation and 7 cases of selective operation. The thickness of flap was 10-25 mm, and the size of the flap ranged from 10.0 cm×7.5 cm to 17.0 cm×8.0 cm. The vascular pedicle of the flap was anastomosed with the snuff nest branch of the radial artery (12 cases), the main radial artery (7 cases), and there accompanying vein, and the intercostal nerve cutaneous branch of the flap was anastomosed with the lateral cutaneous nerve of the forearm. The donor site was closed directly (14 cases) or repaired with medium thickness skin graft (5 cases). RESULTS: All of the flaps and skin grafts survived; the wounds in the donor and recipient sites healed by first intention. All 19 patients were followed up 10- 18 months, with an average of 12.7 months. After operation, the appearance and function of the hand recovered well, and there was no flap bloated. The two-point discrimination of the flap was 7-11 mm, with an average of 8.8 mm. Only linear scars left in the patients with direct closure of the donor site. The sensory function of the donor site was not significantly affected, and the hand function recovered satisfactorily. CONCLUSION: Free sensate intercostal artery perforator flap is a valuable and reliable technique for the hand soft tissue defect.

Application of Electrochemical Atomic Force Microscopy (EC-AFM) in the Corrosion Study of Metallic Materials.

Electrochemical atomic force microscopy (EC-AFM), a branch of a scanning probe microscopy (SPM), can image substrate topography with high resolution. Since its inception, it was extended to a wide range of research areas through continuous improvement. The presence of an electrolytic cell and a potentiostat makes it possible to observe the topographical changes of the sample surface in real time. EC-AFM is used in in situ corrosion research because the samples are not required to be electrically conductive. It is widely used in passive film properties, surface dissolution, early-stage corrosion initiation, inhibitor efficiency, and many other branches of corrosion science. This review provides the research progress of EC-AFM and summarizes the extensive applications and investigations using EC-AFM in corrosion science.

Evolution of the Corrosion Product Film on Nickel-Aluminum Bronze and Its Corrosion Behavior in 3.5 wt % NaCl Solution.

The in-situ studies of the corrosion product film on nickel-aluminum bronze are significant for explaining the mechanism of its corrosion resistance. In this paper, the corrosion behavior of nickel-aluminum bronze and the formation process of the protective film in 3.5 wt % NaCl solution are systematically investigated. The results of scanning electron microscope analysis and electrochemical tests indicate that the corrosion resistance of nickel-aluminum bronze is improved due to the formation of the corrosion product film. The change of local electrochemical property on the corrosion product film during the immersion time is evaluated via in-situ scanning vibrating electrode technique, and it reveals the evolution rules of ionic flux in real time. The formation process of the protective film on different phases in nickel-aluminum bronze is observed directly by in-situ atomic force microscopy as height change measurements. The α phases at different locations present different corrosion behaviors, and the lamellar α phase within the α + κIII eutectoid structure gets more serious corrosion attack. The κ phases establish a stable and dense protective film in short time, preventing the corrosion attack effectively. The ß' phase, however, suffers the most serious corrosion damage until a protective film is formed after 150 min of immersion.

Self-Assembly of Graphene-Encapsulated Cu Composites for Nonenzymatic Glucose Sensing.

Cu has recently received great interest as a potential candidate for glucose sensing to overcome the problems with noble metals. In this work, reduced graphene oxide-encapsulated Cu nanoparticles (Cu@RGO) have been prepared via an electrostatic self-assembly method. This core/shell composites were found to be more stable than conventional Cu-decorated graphene composites and bare copper nanoparticles in an air atmosphere because the graphene shell can effectively protect the Cu nanoparticles from oxidation. In addition, the obtained Cu@RGO composites also showed an outstanding electrocatalytic activity toward glucose oxidation with a wide linear detection range of 1 µM to 2 mM, low detection limit of 0.34 µM (S/N = 3), and a sensitivity of 150 µA mM-1 cm-2. Moreover, Cu@RGO composites exhibited a satisfactory reproducibility, selectivity, and long effective performance. These excellent properties indicated that Cu@RGO nanoparticles have great potential application in glucose detection.

Microstructure and nanoindentation behavior of Cu composites reinforced with graphene nanoplatelets by electroless co-deposition technique.

A reduced graphene oxide/copper (RGO/Cu) composite was fabricated by a surfactant free, electroless co-deposition technique. The graphene oxide (GO) sheets were reduced and RGO homogeneous distributed into the copper matrix. On the basis of nanoindentation, the presence of RGO and the increase of its content in matrix significantly raised the hardness of RGO/Cu composites. Here, the relevant strengthening effect and mechanisms involved in RGO-reinforced Cu composites were systematically evaluated. Especially, the addition of RGO in Cu matrix led to the compressive micro-strain, and the resulted distortion of the lattice parameter was calculated based on Cohen's method. However, excessive addition of GO in the electrolyte could decrease the mechanical performance due to agglomeration of RGO. Apparently, the optimal concentration for GO dispersion in co-deposition solution was deserved to discuss. After a serious of relative experiments, we could get a conclusion that this method provided a new pathway for embedded graphene into the metal matrix to improve the mechanical properties of RGO-reinforced materials.