Silver Nanowire-Based Transparent Electrodes for V2O5 Thin Films with Electrochromic Properties.

The development of electrochromic systems, known for the modulation of their optical properties under an applied voltage, depends on the replacement of the state-of-the-art ITO (In2O3:Sn) transparent electrode (TE) as well as the improvement of electrochromic films. This study presents an innovative ITO-free electrochromic film architecture utilizing oxide-coated silver nanowire (AgNW) networks as a TE and V2O5 as an electrochromic oxide layer. The TE was prepared by simple spray deposition of AgNWs that allowed for tuning different densities of the network and hence the resistance and transparency of the film. The conformal oxide coating (SnO2 or ZnO) on AgNWs was deposited by atmospheric-pressure spatial atomic layer deposition, an open-air fast and scalable process yielding a highly stable electrode. V2O5 thin films were then deposited by radio frequency magnetron sputtering on the AgNW-based TE. Independent of the oxide's nature, a 20 nm protective layer thickness was insufficient to prevent the deterioration of the AgNW network during V2O5 deposition. On the contrary, crystalline V2O5 films were grown on 30 nm thick ZnO or SnO2-coated AgNWs, exhibiting a typical orange color. Electrochromic characterization demonstrated that only V2O5 films deposited on 30 nm thick SnO2-coated AgNW showed characteristic oxidation-reduction peaks in the Li+-based liquid electrolyte associated with a reversible orange-to-blue color switch for at least 500 cycles. The electrochromic key properties of AgNW/SnO2 (30 nm)/V2O5 films are discussed in terms of structural and morphological changes due to the AgNW network and the nature and thickness of the two protective oxide coatings.

Decoration of Gold and Platinum Nanoparticle Catalysts by 1 nm Thick Metal Oxide Overlayer and Its Effect on the CO Oxidation Activity.

Exfoliated M-Al layered double hydroxide (M-Al LDH; M = Mg, Co, Ni, and Zn) nanosheets were adsorbed on Au/SiO2 and calcined to transform LDH into mixed metal oxides (MMOs) and yield Au/SiO2 coated with a thin MMO overlayer. These catalysts showed a higher catalytic activity than pristine Au/SiO2. In particular, the 50% CO conversion temperature decreased by more than 250 °C for Co-Al MMO-coated Au/SiO2. In contrast, the deposition of CoAlOx on Au/SiO2 by impregnation or the deposition of Au on Co-Al MMO-coated SiO2 resulted in a worse catalytic activity. Moreover, the presence of a thick MMO overlayer decreased the catalytic activity, suggesting that the control of the overlayer thickness to less than 1 nm is a requisite for obtaining a high catalytic activity. Moreover, the thin Co-Al MMO overlayer on Au/SiO2 possessed abundant oxygen vacancies, which would play an important role in O2 activation, resulting in a highly active interface between Au and the defect-rich MMO on the Au NP surface. Finally, this can be applied to Pt/SiO2, and the obtained Co-Al MMO-coated Pt/SiO2 also exhibited a much improved catalytic activity for CO oxidation.

Polyaniline-metal oxide coatings for biocidal applications: Mechanisms of activation and deactivation.

Metal oxide (MO) coatings (e.g. TiO2, ZnO, and CuO) have shown great promise to inactivate pathogenic bacteria, maintain self-cleaning surfaces, and prevent infectious diseases spread via surface contact. Under light illumination, the antibacterial performance of photoactive MO coatings is determined by reactive oxygen species (ROS) generation. However, several drawbacks, such as photo-corrosion and rapid electron-hole recombination, hinder the ROS production of MO coatings and diminish their antibacterial efficiency. In this study, we employed polyaniline (PANI), an inexpensive and easy-to-synthesize conductive polymer, to fabricate polyaniline-metal oxide composite (PMC) films. The antibacterial performance of PMC films was tested using E. coli as the model bacterium and Lake Michigan water (LMW) as the background medium and revealed enhanced antibacterial performance relative to MO coatings alone (approximately 75-90 % kill of E. coli by PMC coatings in comparison to 20-40 % kill by MO coatings), which is explained by an increase in the ROS yields of PMC. However, with repeated use, the antibacterial performance of the PMC coatings is diminished due to deprotonation of the PANI in the neutral/slightly basic aqueous environment of LMW. Overall, PANI can enhance the antibacterial performance of MO coatings, but efforts need to be directed to preserve or regenerate PMC stability under environmental conditions and applications.

Reduced Graphene Oxide Coating LiFePO4 Composite Cathodes for Advanced Lithium-Ion Battery Applications.

Recently, the application of LiFePO4 (LFP) batteries in electric vehicles has attracted extensive attention from researchers. This work presents a composite of LFP particles trapped in reduced graphene oxide (rGO) nanosheets obtained through the high-temperature reduction strategy. The obtained LiFePO4/rGO composites indicate spherical morphology and uniform particles. As to the structure mode of the composite, LFP distributes in the interlayer structure of rGO, and the rGO evenly covers the surface of the particles. The LFP/rGO cathodes demonstrate a reversible specific capacity of 165 mA h g-1 and high coulombic efficiency at 0.2 C, excellent rate capacity (up to 10 C), outstanding long-term cycling stability (98%) after 1000 cycles at 5 C. The combined high electron conductivity of the layered rGO coating and uniform LFP particles contribute to the remarkable electrochemical performance of the LFP/rGO composite. The unique LFP/rGO cathode provides a potential application in high-power lithium-ion batteries.

Design of reduced graphene oxide coating carbon sub-microspheres hierarchical nanostructure for ultra-stable potassium storage performance.

The development of high-performance carbon-based anode materials is still a significant challenge for K-ion storage. In our work, we designed reduced graphene oxide coating carbon sub-microspheres hierarchical nanostructure (CS@RGO) hierarchical nanostructure via a simple freeze-drying and subsequent pyrolysis as anode for K-ion batteries (KIBs), which presented an excellent electrochemical performance for K-ion storage, with a reversible specific capacity of 295 mAh g-1 after 100 cycles at 100 mAh g-1. Even at a high current density of 1 A g-1, our CS@RGO still achieves ultra-stable K-ion storage of 200 mAh g-1 at 1 A g-1 after 5000 cycles almost without capacity fade. According to the galvanostatic intermittent titration technique result, the CS@RGO hybrid receives a high average diffusion coefficient of 7.35 × 10-8 cm2 s-1, contributing to the rapid penetration of K-ion, which facilitates the enhancement of electrochemical performance for KIBs. Besides, we also use Raman spectra to investigate the electrochemical behavior of our CS@RGO hybrid for K-ion storage and confirm the reaction process. We believe that our work will offer the opportunity to enable ultra-stable carbon-based materials by the structure design in the K-ion battery field.

Effect of different coatings on the structure and performance of three-dimensional ordered macropores La0.7Ce0.3CoO3 catalysts.

In this work, monolithic catalysts with single coating Ce0.75Zr0.25O2, Al2O3 and composite coating Ce0.75Zr0.25O2-Al2O3 were prepared by PMMA hard template-excessive impregnation method with 3DOM La0.7Ce0.3CoO3 as the active component and cordierite as the carrier, and characterized by SEM, XRD, BET, H2-TPR, and XPS, and the catalytic performance for toluene was tested. The results showed that the active components of 3DOM La0.7Ce0.3CoO3/Ce0.75Zr0.25O2-Al2O3/cordierite catalyst were highly dispersed, forming a complete macroporous structure with the largest specific surface area (10.57 m2·g-1), high surface adsorbed oxygen concentration, and good low-temperature reducibility. Its catalytic activity (T50% = 103℃, T90% = 218℃) for toluene was obviously better than the others. According to the comprehensive analysis, the improvement of the performance of the catalyst may benefit from the excellent physicochemical properties and the synergistic effect between Ce0.75Zr0.25O2-Al2O3 composite coating and active components.

Efficient Removal of Methylene Blue and Ciprofloxacin from Aqueous Solution Using Flower-like, Nanostructured ZnO Coating under UV Irradiation.

Flower-like ZnO architectures assembled with many nanorods were successfully synthesized through Thermionic Vacuum Arc, operated both in direct current (DC-TVA) and a pulsed mode (PTVA), and coupled with annealing in an oxygen atmosphere. The prepared coatings were analysed by scanning-electron microscopy with energy-dispersive X-ray-spectroscopy (SEM-EDX), X-ray-diffraction (XRD), and photoluminescence (PL) measurements. By simply modifying the TVA operation mode, the morphology and uniformity of ZnO nanorods can be tuned. The photocatalytic performance of synthesized nanostructured ZnO coatings was measured by the degradation of methylene-blue (MB) dye and ciprofloxacin (Cipro) antibiotic. The ZnO (PTVA) showed enhancing results regarding the photodegradation of target contaminants. About 96% of MB molecules were removed within 60 min of UV irradiation, with a rate constant of 0.058 min-1, which is almost nine times higher than the value of ZnO (DC-TVA). As well, ZnO (PTVA) presented superior photocatalytic activity towards the decomposition of Cipro, after 240 min of irradiation, yielding 96% degradation efficiency. Moreover, the agar-well diffusion assay performance against both Gram-positive and Gram-negative bacteria confirms the degradation of antibiotic molecules by the UV/ZnO (PTVA) approach, without the formation of secondary hazardous products during the photocatalysis process. Repeated cyclic usage of coatings revealed excellent reusability and operational stability.

Enhancing the Intrinsic and Extrinsic Stability of Halide Perovskite Nanocrystals for Efficient and Durable Optoelectronics.

Over the past few years, metal halide perovskite nanocrystals have been at the forefront of colloidal semiconductor nanomaterial research because of their fascinating properties and potential applications. However, their intrinsic phase instability and chemical degradation under external exposures (high temperature, water, oxygen, and light) are currently limiting the real-world applications of perovskite optoelectronics. To overcome these stability issues, researchers have reported various strategies such as doping and encapsulation. The doping improves the optical and photoactive phase stability, whereas the encapsulation protects the perovskite NCs from external exposures. This perspective discusses the rationale of various strategies to enhance the stability of perovskite NCs and suggests possible future directions for the fabrication of optoelectronic devices with long-term stability while maintaining high efficiency.

Dual-function monolithic enzyme reactor based on dopamine/graphene oxide coating for simultaneous protein enzymatic hydrolysis and glycopeptide enrichment.

A new dual-function enzyme reactor was prepared based on a dopamine/graphene oxide coated boron affinity monolithic column, which can be used for simultaneous protein enzymatic hydrolysis and glycopeptide enrichment. Firstly, a boron affinity monolithic column was prepared as the carrier for enzyme reactor. Secondly, the monolithic column was coated with dopamine/graphene oxide to provide higher specific surface area for the increase in the amount of trypsin bound. Then, dopamine can self-polymerize under alkaline conditions to produce multiple reaction sites. By the Schiff base reaction and Michael addition reaction with amino, sulfhydryl groups to trypsin, enzyme were immobilized on the boron affinity monolithic carrier. The enzyme activity was characterized by kinetic parameters maximum rate (Vmax) of the enzyme reaction and Michaelis constant (Km). Km of the dual-function enzyme reactors doped with PDA/GO and without PDA/GO were 34.37 and 120.93 mM, Vmax were 1.35 and 3.35 mM/min, respectively. The performance of the dual-function enzyme reactor was evaluated by protein extraction of mouse liver. After digested by the dual-function enzyme reactor, the number of peptides was 4,801, which was 960 more than the number of peptides in the solution digestion. At the same time, the dual-function enzyme reactor displayed the ability to capture cis-dihydroxy compounds specificly. A total of 55 glycopeptides were enriched in the dual-functional enzyme reactor, corresponding to 33 glycoproteins. The dual-function enzyme reactor provided repeatable performance and robust with long-term storage.

Exfoliation Resistance, Microstructure, and Oxide Formation Mechanisms of the White Oxide Layer on CP Ti and Ti-Nb-Ta-Zr Alloys.

We found that specific biomedical Ti and its alloys, such as CP Ti, Ti-29Nb-13Ta-4.6Zr, and Ti-36Nb-2Ta-3Zr-0.3O, form a bright white oxide layer after a particular oxidation heat treatment. In this paper, the interfacial microstructure of the oxide layer on Ti-29Nb-13Ta-4.6Zr and the exfoliation resistance of commercially pure (CP) Ti, Ti-29Nb-13Ta-4.6Zr, and Ti-36Nb-2Ta-3Zr-0.3O were investigated. The alloys investigated were oxidized at 1273 or 1323 K for 0.3-3.6 ks in an air furnace. The exfoliation stress of the oxide layer was high in Ti-29Nb-13Ta-4.6Zr and Ti-36Nb-2Ta-3Zr-0.3O, and the maximum exfoliation stress was as high as 70 MPa, which is almost the same as the stress exhibited by epoxy adhesives, whereas the exfoliation stress of the oxide layer on CP Ti was less than 7 MPa, regardless of duration time. The nanoindentation hardness and frictional coefficients of the oxide layer on Ti-29Nb-13Ta-4.6Zr suggested that the oxide layer was hard and robust enough for artificial tooth coating. The cross-sectional transmission electron microscopic observations of the microstructure of oxidized Ti-29Nb-13Ta-4.6Zr revealed that a continuous oxide layer formed on the surface of the alloys. The Au marker method revealed that both in- and out-diffusion occur during oxidation in Ti-29Nb-13Ta-4.6Zr and Ti-36Nb-2Ta-3Zr-0.3O, whereas only out-diffusion governs oxidation in CP Ti. The obtained results indicate that the high exfoliation resistance of the oxide layer on Ti-29Nb-13Ta-4.6Zr and Ti-36Nb-2Ta-3Zr-0.3O are attributed to their dense microstructures composing of fine particles, and a composition-graded interfacial microstructure. On the basis of the results of our microstructural observations, the oxide formation mechanism of the Ti-Nb-Ta-Zr alloy is discussed.

Is an anodizing coating associated to the photobiomodulation able to optimize bone healing in ovariectomized animal model?

This in vivo study investigated whether the bioactivity of anodizing coating, produced by plasma electrolytic oxidation (PEO), on mini-plate in femur fracture could be improved with the association of photobiomodulation (PBM) therapy. From the 20 ovariectomized Wistar female rats, 8 were used for model characterization, and the remaining 12 were divided into four groups according to the use of PBM therapy by diode laser (808 nm; power: 100 mW; energy: 6.0 J; energy density: 212 J/cm2; power density: 3.5 W/cm2) and the type of mini-plate surface (commercially pure titanium mini-plate -cpTi- and PEO-treated mini-plate) as follow: cpTi; PEO; cpTi/PBM; and PEO/PBM. After 60 days of surgery, fracture healing underwent microstructural, bone turnover, histometric, and histologic adjacent muscle analysis. Animals of groups with PEO and PBM showed greater fracture healing than cpTi control group under histometric and microstructural analysis (P < 0.05); however, bone turnover was just improved in PBM's groups (P < 0.05). there was no difference between cpTi and PEO without PBM (P > 0.05). Adjacent muscle analysis showed no metallic particles or muscle alterations in all groups. PEO and PBM are effective strategies for bone repair in fractures, however their association does not provide additional advantages.

Comparison between Plasma Electrolytic Oxidation Coating and Sandblasted Acid-Etched Surface Treatment: Histometric, Tomographic, and Expression Levels of Osteoclastogenic Factors in Osteoporotic Rats.

Plasma electrolytic oxidation (PEO) has been a promising surface coating with better mechanical and antimicrobial parameters comparing to conventional treatment surfaces. This study evaluated the peri-implant bone repair using (PEO) surface coatings compared with sandblasted acid (SLA) treatment. For this purpose, 44 Wistar rats were ovariectomized (OVX-22 animals) or underwent simulated surgery (SS-22 animals) and received implants in the tibia with each of the surface coatings. The peri-implant bone subsequently underwent molecular, microstructural, bone turnover, and histometric analysis. Real-time PCR showed a higher expression of osteoprotegerin (OPG), receptor activator of nuclear kappa-B ligand (RANKL), and osteocalcin (OC) proteins in the SLA/OVX and PEO/SS groups (p < 0.05). Computed microtomography, confocal microscopy, and histometry showed similarity between the PEO and SLA surfaces, with a trend toward the superiority of PEO in OVX animals. Thus, PEO surfaces were shown to be promising for enhancing peri-implant bone repair in ovariectomized rats.

Microstructure and Properties of Nanostructured Coating on Ti6Al4V.

Implant surface properties of Ti6Al4V alloy that is currently used as a biocompatible material because of a variety of unique properties can be improved by a self-organized TiO2 layer. The TiO2 nanotubes forming on the titanium-based materials is a relatively recent technology for the surface properties modification and represents pronounced potential in promoting cell adhesion, proliferation, and differentiation that facilitate an implant osseointegration. This work focuses on the influence of surface treatment quality and anodic oxidation parameters on the structure features and properties of TiO2 nanotube coatings. The nanotubes were formed on Ti6Al4V alloy substrates by simultaneous surface oxidation and controlled dissolving of an oxide film in the presence of fluorine ions. The anodization process on ground or polished samples was performed at experimental condition of 30 V for 1 h. The selected anodized samples were heat treated for 2 h at 500 °C under flowing argon. All samples were characterized by scanning electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. The corrosion rate in physiological solution reached 0.0043, 0.0182, and 0.0998 mm per year for the samples in polished and not-anodized, as-anodized, and anodized-heat treated conditions, respectively.

Enhanced Osseointegration of Titanium Alloy Implants with Laser Microgrooved Surfaces and Graphene Oxide Coating.

Rapid and effective osseointegration, as a critical factor in affecting the success rate of titanium (Ti) implants in orthopedic applications, is significantly affected by their surface microstructure and chemical composition. In this work, surface microgrooved Ti-6Al-4V alloys with graphene oxide coating (Ti-G-GO) were fabricated by a combination of laser processing and chemical assembly techniques. The osteogenic capability in vitro and new bone formation in vivo of the implants were systematically investigated, and biomechanical pull-out tests of the screws were also performed. First, in vitro studies indicated that the optimal microgroove width of the titanium alloy surface was 45 µm (Ti-G), and the optimum GO concentration was 1 mg/mL. Furthermore, the effects of the surface microstructure and GO coating on the in vitro bioactivity were investigated through culturing bone marrow mesenchymal stem cells (BMSCs) on the surface of titanium alloy plates. The results showed that the BMSCs cultured on the Ti-G-GO group exhibited the best adhesion, proliferation, and differentiation, compared with that on the Ti-G and Ti groups. Micro-computed tomography evaluation, histological analysis, and pull-out testing demonstrated that both Ti-G and Ti-G-GO implants had the higher osseointegration than the untreated Ti implant. Moreover, the osteogenic capability of the Ti-G-GO group appeared to be superior to that of the Ti-G group, which could be attributed to the improvement of surface wettability and apatite formation by the GO coatings. These results suggest that the combination of the microgroove structure and GO coatings exhibits considerable potential for enhancing the surface bioactivation of materials, and the combination modification is expected to be used on engineered titanium alloy surfaces to enhance osseointegration for orthopedic applications.

Development of an Oxygen Sensitive Model Gel System to Detect Defects in Metal Oxide Coated Multilayer Polymeric Films.

Metal oxide coated multilayered polymeric pouches provide a suitable alternative to foil-based packaging for shelf-stable products with extended shelf-life. The barrier performance of these films depends upon the integrity of the metal oxide coating which can develop defects as a result of thermal processing and improper handling. In this work, we developed a methodology to visually identify these defects using an oxygen-sensitive model gel system. Four pouches with different metal oxide coatings: MOA (Coated PET), MOB (SiOx -coated PET), MOC (Overlayer-AlOx -Organic-coated PET), MOD (Overlayer-SiOx -coated PET) were filled with water and retort-processed for 30 and 40 min at 121 °C. After processing, the pouches were cut open, dried and subsequently filled with a gel containing methylene blue that changes color in the presence of oxygen. The pouches were then stored at 23 and 40 °C for 180 and 90 days, respectively. Defects were identified by observing the localized color change from yellow to blue in the packaged gel. These observations were confirmed through measurement of oxygen and water vapor transmission rates, as well as SEM and CLSM analyses. The MOC pouches showed the least change in barrier properties after thermal processing. This was due to crosslinking in the organic coating and protection provided by the overlayer. The melting enthalpy of all films increased significantly (P < 0.05) after sterilization. This may increase the brittleness of the substrates after processing. Findings may be used to improve the barrier performance of metal oxide coated polymeric films intended for food packaging applications. PRACTICAL APPLICATION: In this study, we developed a methylene blue-based, oxygen-sensitive model gel system to identify defects in metal oxide coated polymeric structures induced by thermal processing and mechanical stresses. We also performed a comprehensive analysis of these defects through CLSM and SEM. The gel system and methodology developed may be useful in the design and development of high barrier metal oxide coated films.

Effect of Graphene Oxide Coating on Natural Fiber Composite for Multilayered Ballistic Armor.

Composites with sustainable natural fibers are currently experiencing remarkably diversified applications, including in engineering industries, owing to their lower cost and density as well as ease in processing. Among the natural fibers, the fiber extracted from the leaves of the Amazonian curaua plant (Ananas erectifolius) is a promising strong candidate to replace synthetic fibers, such as aramid (Kevlar™), in multilayered armor system (MAS) intended for ballistic protection against level III high velocity ammunition. Another remarkable material, the graphene oxide is attracting considerable attention for its properties, especially as coating to improve the interfacial adhesion in polymer composites. Thus, the present work investigates the performance of graphene oxide coated curaua fiber (GOCF) reinforced epoxy composite, as a front ceramic MAS second layer in ballistic test against level III 7.62 mm ammunition. Not only GOCF composite with 30 vol% fibers attended the standard ballistic requirement with 27.4 ± 0.3 mm of indentation comparable performance to Kevlar™ 24 ± 7 mm with same thickness, but also remained intact, which was not the case of non-coated curaua fiber similar composite. Mechanisms of ceramic fragments capture, curaua fibrils separation, curaua fiber pullout, composite delamination, curaua fiber braking, and epoxy matrix rupture were for the first time discussed as a favorable combination in a MAS second layer to effectively dissipate the projectile impact energy.

Surface Modification of Ni-Rich LiNi0.8Co0.1Mn0.1O2 Cathode Material by Tungsten Oxide Coating for Improved Electrochemical Performance in Lithium-Ion Batteries.

Ni-rich NCM-based positive electrode materials exhibit appealing properties in terms of high energy density and low cost. However, these materials suffer from different degradation effects, especially at their particle surface. Therefore, in this work, tungsten oxide is evaluated as a protective inorganic coating layer on LiNi0.8Co0.1Mn0.1O2 (NCM-811) positive electrode materials for lithium-ion battery (LIB) cells and investigated regarding rate capability and cycling stability under different operation conditions. Using electrochemical impedance spectroscopy, the interfacial resistance of uncoated and coated NCM-811 electrodes is explored to study the impact of the coating on lithium-ion diffusion. All electrochemical investigations are carried out in LIB full cells with graphite as a negative electrode to ensure better comparability with commercial cells. The coated electrodes show an excellent capacity retention for the long-term charge/discharge cycling of NCM-811-based LIB full cells, i.e., 80% state-of-health after more than 800 cycles. Furthermore, the positive influence of the tungsten oxide coating on the thermal and structural stability is demonstrated using postmortem analysis of aged electrodes. Compared to the uncoated electrodes, the surface-modified electrodes show less degradation effects, such as particle cracking on the electrode surface and improvement of the thermal stability of NCM-811 in the presence of electrolyte.

Electrophoretic Deposition of Magnesium Oxide Nanoparticles on Magnesium: Processing Parameters, Microstructures, Degradation, and Cytocompatibility.

Magnesium (Mg) and its alloys are a class of promising materials for biodegradable orthopedic and craniomaxillofacial implants; however, rapid release of hydrogen gas remains a key challenge for clinical translation. This study reported the optimal parameters of electrophoretic deposition (EPD), at which magnesium oxide nanoparticles (nMgO) could be deposited onto Mg substrates with homogeneous surface morphology and elemental distribution. The results showed that the distribution and uniformity of the nMgO coatings on Mg improved when the nMgO concentration in ethanol increased and the time of applied voltage decreased. The nMgO-coated Mg showed a homogeneous surface and distinct degradation mode during the 9-day immersion studies in revised simulated body fluid (r-SBF) and Dulbecco's modified Eagle's medium (DMEM), when compared with the noncoated Mg controls. The nMgO coating initially mitigated hydrogen gas formation. The degradation layer on nMgO-coated Mg was thicker than the noncoated Mg and enriched with Ca and P that are favorable for skeletal implant applications. In the direct culture study with bone marrow derived mesenchymal stem cells (BMSCs) in vitro, the cell adhesion density and morphology were not affected by the solubilized degradation products released by the nMgO-coated Mg under indirect contact. However, at the cell-biomaterial interface, the cell spreading decreased under direct contact, possibly because of the continuous dynamic degradation of the samples. The electrophoretically deposited nMgO coatings on Mg-based medical implants should be further studied to improve the coating-substrate and cell-material interfaces for clinical applications.

Chromium oxide coatings with the potential for eliminating the risk of chromium ion release in orthopaedic implants.

Chromium oxide coatings prepared by radiofrequency reactive magnetron sputtering on stainless steel substrates were exposed to Ringer's physiological solution and tested for their electrochemical corrosion stability using an open circuit potential measurement, potentiodynamic polarization, electrochemical impedance spectroscopy and Mott-Schottky analysis. The coatings were found to be predominantly Cr2O3, based on the observation of the dominance of [Formula: see text] and Eg symmetric modes in our Raman spectroscopic investigation and the Eu vibrational modes in our Fourier transform infrared spectroscopic measurements on the coatings. We investigated for the presence of chromium ions in Ringer's solution after all of the above electrochemical tests using atomic absorption spectroscopy, without finding a trace of chromium ions at the ppm level for coatings tested under open circuit and at the lower potentials implants are likely to experience in the human body. The coatings were further exposed to Ringer's solution for one month and tested for adhesion strength changes, and we found that they retained substantial adhesion to the substrates. We expect this finding to be significant for future orthopaedic implants where chromium ion release is still a major challenge.

The synthesis of novel LiNiPO4 core and Co3O4/CoO shell materials by combining them with hard-template and solvothermal routes.

Pure CoO and Co3O4 surface-modified LiNiPO4 nanoscale powders are successfully synthesized for the first time by newly elaborated hard-template and solvothermal methods. Using this extraordinary technique, LiNiPO4 particles are coated with a thin CoO or Co3O4 layer with a perfect core-shell morphology. The technique's positive contribution to electrochemistry is investigated in detail. The HR-TEM analysis proves that it possible to achieve a continuous surface coverage of about 5nm, a result that contributes towards solving the chronic electrochemical problems of high-voltage cathode material. Our data reveal that cobalt cannot be diffused into the LiNiPO4 crystal system during the calcination process and that the LiNiPO4@CoO cathode demonstrates superior cycle stability and specific capacity at relatively low rates. The LiNiPO4@CoO cathode exhibits the best electrochemical properties, achieving a discharge capacity of 149mAhg-1 at 0.1C rate, and shows almost 82% capacity retention after 80 charge-discharge cycles. It therefore achieves partial success in terms of improving the electrochemical properties of the LiNiPO4 cathode material. This is especially crucial for energy storage with regard to electric vehicles and plug-in hybrid electric applications.