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Marine biofouling is a major issue deteriorating the service performance and lifespan of marine infrastructures. The development of a durable, long-term, and environment-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime engineering. Herein, we developed a Cu-Ti composite antifouling coating with micron-sized alternating laminated-structure of Cu/Ti by plasma spraying of mechanically mixed Cu/Ti powders. The coating was designed to enable controlled release of Cu ions through galvanic dissolution of Cu laminates from the Cu/Ti micro-galvanic cell in aqueous solution. Results showed that remarkable antifouling efficiency against bacterial survival and adhesion up to ∼100 % was achieved for the Cu-Ti coating. Cu/Ti micro-galvanic cell was in-situ formed within Cu-Ti coating and responsible for its Cu ions release. The successive dissolution of Cu laminates resulted in the formation of micro-channels under Ti laminates near surface, which contributed to controlled slow Cu ions release and self-polishing effect. Thus, environment-friendly antifouling capability and ∼200 % longer antifouling lifetime than that of the conventional organic antifouling coatings can be achieved for the Cu-Ti coating. On the other hand, as compared to the conventional organic antifouling coatings, the Cu-Ti composite coating presented much higher mechanical durability due to its strong adhesion strength, excellent mechanical properties, and two orders lower wear rate. The present laminated Cu-Ti coating exhibits combination of outstanding antifouling performance and high mechanical durability, which makes this coating very potentially candidates in marine antifouling application.

As an important precipitate in Zr-alloy, detailed study on the oxidation behavior of Zr(Fe,Nb)2 in atomic scale will help to develop safer materials for reactors. In this study, Zr(Fe,Nb)2 intermetallic was fabricated and exposed to subcritical water (320 °C, 15.5 MPa). On oxidation frontier, the interplay between element diffusion and structure evolution was analyzed. The oxidation process started with the incorporation of oxygen in local strips, which was perpendicular to the direction of oxygen diffusion. Fe was segregated from the oxygen-rich strips via an uphill diffusion process along {001} lattice plane. The “spinodal decomposition”-like phenomenon was observed and discussed.

Severe deviation in structure and chemistry at grain boundaries has been regarded as the source of the poor conductivity of Li3xLa2/3-xTiO3. In this work, we report an in situ grain boundary engineering method to address this bottleneck. A lithium-rich electrolyte, Li3OCl, was introduced into Li3xLa2/3-xTiO3 to replenish lithium at the grain boundaries. Both the Li-gain on the boundary and generation of a Li-rich grain-engineered layer contributed to an optimized grain boundary conductivity of 1.52 × 10−4 (S/cm) and a depressed activation energy of 0.32 eV for grain boundary. Full batteries were further employed to demonstrate the enhancement in conductivity.

Ultra-fast detection of hazardous gases with high selectivity is important for environmental safety monitoring. In this study, we report a Li0.5La0.5TiO3 (LLTO) sensor with an ultrafast response to H2S. We used a simple solvothermal method to controllably synthesize hollow LLTO nano-spheres. The LLTO nano-spheres had a porous surface structure, which provides sufficient channels for diffusion of H2S gas. Response/recovery speeds of 0.7 s/0.8 s were achieved at an optimum working temperature of 340 °C. To further improve the response, the band structure was modulated by Fe doping (FLTO). When doped with Fe3+, more oxygen vacancies were generated which enhanced the chemical absorption of O2 and generation of active oxygen species (O− and O2−). Furthermore, the band gap was also narrowed and the conduction band was elevated by 0.44 eV, which promoted charge transfer from the conduction band of FLTO to chemisorbed gas molecules. After doping, the response was 5.5 times as great as that of the pristine LLTO sensor for 30 ppm H2S and the optimum temperature decreased to 300 °C. In addition, the detection limit was as low as 100 ppb. The doped LLTO sensor also had good repeatability and long-term stability.

The composite polymer electrolytes, consisting of a flexible matrix and superb fast ion conductor are promising for large-scale practical application in safer lithium metal batteries. The quantification of polymer structure evolution induced by the inorganic filler was rarely reported. Here, a designer cubic argyrodite Li6PS5X sulfide electrolyte was fabricated by a solid reaction. A stoichiometry deviation by increasing S and Li, reducing Cl contents, leads to a novel electrolyte of Li6.25PS5.25Cl0.75 with high conductivity of 1.0 mS cm−1 and low activation energy of 0.14 eV at room temperature. The off-stoichiometry Li6PS5X sulfide electrolyte Li6.25PS5.25Cl0.75 was used as active filler for polyethylene oxide. Small angle X-ray scattering experiment indicates that the Li6.25PS5.25Cl0.75 triggers a pronounced structure evolution in the matrix. As a result, Li-ion diffusion pathway is expanded significantly by the Li6.25PS5.25Cl0.75 additives. An optimum ionic conductivity of 1.4 mS cm−1 at 70 °C for CPEs-1 was obtained, and a LFP/Li demo battery delivers a high capacity retention of 91.1% for 100 cycles at 0.2 C.

In this study, Li0.35La0.55TiO3 (LLTO) was coupled with Al-doped lithium lanthanum zirconate (LLZO) to improve the grain boundary and total conductivity. The obtained ceramic pellets (LLTZO) demonstrated a recordable grain boundary and total conductivity of 3.41 × 10−4 and 3.03 × 10−4 S/cm, respectively. The obtained results establish that the heteroatoms can perturb the cation ordered structure and improve the 3D conductivity in grain bulk. In addition, the residual Al-doped LLZO on the grain boundary led to a decline in the boundary resistance. An LiFeCoPO4 |Li cell was adopted to demonstrate the enhanced conductivity of LLTO. The solid state battery rendered a specific capacity of over 101.2 mAhg−1 after 300 cycles at a relatively high rate of 0.5C. It is established from the experiments that manufacturing a solid battery using the all-coating technique provides a promising approach to achieve a practical application.

A LiNi0.8Co0.15Al0.05O2 (NCA) solid battery was assembled by coupling an NCA cathode with a polyvinylidene fluoride (PVDF)/Li6.75La3Z1.75Ta0.25O12 (LLZTO) composite polymer electrolyte and a Li ano...

Natural grown ZrO2 cannot effectively protect Zr alloy due to the poor phase stability. In this work, a pre-defected ZrO2 coating was fabricated on Zr alloy and further bombarded by Ar8+. A spontaneous martensitic transformation in ZrO2 coating was triggered by lattice distortion and gradient mismatch on the interface. Additionally, Ar8+ bombardment induced the formation of interstitial-vacancy pairs in ZrO2. DFT modeling proved that the interstitial-vacancy pairs were superior in stabilizing T-phase ZrO2, compared with native oxygen vacancies. A mechanism for enhanced corrosion resistance was proposed based on the unique interface and defect state.

Due to cage-like voids in the lattice, skutterudite NiP3 is regarded as a promising negative electrode material with high specific capacity. The fabrication of phosphide based on ceramic routes always leads to multiphase formation and serious agglomeration of particles. The resultant cycle performance is thus to be improved. In this paper, single phase skutterudite NiP3 particles (NNP) were fabricated by the reaction of NiS precursor with red phosphorus. As comparison, skutterudite NiP3 was also prepared by the direct reaction of Ni with red phosphorus (MNP). After 50 cycles, NNP retained 712 mAh g−1 at current density of 159.1 mAg−1, while MNP delivered a capacity less than that of commercial graphite within 16 cycles. According to CV analysis, the improvement in cycling performance of NNP was attributed to an insertion-dominated two-step lithiation process, while MNP undergone a straightforward conversion process. The formation of layer-structured intermediate LixNiP3 phase by an insertion reaction would compete with the direct generation of Li3P and Ni (0) composites by a typical conversion reaction. The improvement in the rating performance originates from the low-impedance of charge transfer and fast migration of Li+ in the electrode of NNP.

Background Persistent host immune responses initiated by oral bacteria protect host against infection but may also elicit the process of sustained periodontal inflammation and subsequent alveolar bone loss. Interleukin-10 (IL-10), an anti-inflammatory cytokine, can downregulate pro-inflammatory cytokine and inhibit neutrophil migration in inflammation. IL-10-expressing regulatory B cells (B10) is termed by negatively regulating immune response through IL-10 and are mainly restricted in CD19+ CD1dhi CD5+ B cells in mice. Our current study was aimed to explore the effect of locally transferred CD19+ CD1dhi CD5+ B cells on inflammation and alveolar bone loss in an experimental periodontitis mouse model. Methods Ligation plus P. gingivalis (Pg) infection was used to induce periodontitis in a mouse model. CD19+ CD1dhi CD5+ B cells were sorted by flow cytometry and transferred into the gingivae immediately on the fifth day after ligation. All the mice were sacrificed on day 14 after ligation. Results H&E staining showed that inflammatory cell infiltration was significantly reduced by the CD19+ CD1dhi CD5+ B cells. Toluidine blue staining showed that the CD19+ CD1dhi CD5+ B cells alleviated alveolar bone loss in the ligature/Pg-induced periodontitis in mice. Immunohistochemical staining showed Receptor Activator of NF-KappaB Ligand (RANKL), Interleukin-1β(IL-1β) and Interleukin-17 (IL-17) were decreased after the CD19+ CD1dhi CD5+ B cell transfer. Immunofluorescent staining showed that IL-10 was increased while the number of Ly6G+ neutrophil and its RANKL production were decreased in gingival tissue. Conclusions These results indicated that locally transferred CD19+ CD1dhi CD5+ B cells may alleviate alveolar bone loss through inhibiting pro-inflammatory cytokine expression and RANKL-expressing neutrophils in the periodontitis mouse model.

The Li0.5La0.5TiO3 (LLTO) is a new sensing material demonstrating ultrafast response to H2S within one second. To further enhance the sensitivity, a LLTO-SnO2 core-shell structure was constructed by the assembly of thin SnO2 nanoflakes on the porous hollow LLTO spheres. The absorption and reaction activity of oxygen on the surface as well as the electron transfer processes were modified and discussed in detail. The formation of oxygen vacancy improves the onset potential of oxygen reduction from 0.61 V to 0.75 V. The effective separation of electrons across the interface helps to take advantage of high response property of SnO2. The response value was improved by 4.5 times than that of pristine LLTO with sub-second response time and excellent stability.

A surfactant free growth method was proposed to get thick MnSi∼1.7 film by exposure of Si(111) substrates to MnCl2 vapor in quartz ampoules. Prior to the growth of silicide film, an amorphous nano SiOx capping layer was introduced on the Si substrate. The capping layer changes the elemental diffusion flux to the reaction interface and facilitates the growth of single phase MnSi∼1.7 film. Optical absorption spectrum demonstrates the existence of a direct band gap∼ 0.78 eV, which agrees well with the theoretical one obtained by density functional theory modeling.

Different configurations of Sn and C films were deposited and used as a planar anode for Li ion battery. The interplay of carbon layer with Sn as supporting and buffering, respectively, was revealed. The suppression on the allotropic transformation to α phase by a carbon layer results in a significantly improved capacity retention rate, which also avoids the crack of Sn film. As expected, a conductive carbon layer improves rating performance. However, a supporting carbon layer (SC) just contributes to the charge transfer process. A DFT approach was used to assess the allotropic transformation process. An additional barrier (∼0.86 eV) exits on the α-β diagram, which is responsible for the irreversibility of α phase back to β phase. An enhanced persistence of β phase in Sn/C anode contributes to cycling performance. A Li rich condition contributes to the stabilization of β-Sn, which is thermodynamically favored. A nano buffering carbon (BC) layer can evidently alleviate the side reaction on Sn surface, which in turn promotes the diffusion of Li ions in electrode and generates a Li rich condition. The direct contact of Sn with electrolyte leads to serious accumulation of α-Sn during cycling and results in a poor cycling performance. By the synergistic effect of BC and SC, a sandwich C/Sn/C structure demonstrates an enchantment in electrochemical behavior.

The loss of structure integrity and intrinsic poor conductivity of SnO2 anode are regarded as the main origination of capacity decay. In this work, a serious phase separation of β → α during cycling was confirmed and related with the capacity decaying closely. To address these challenges, an amorphous transparent (Sn, Nb)O2 with high conductivity was fabricated. The Nb dopant with a full oxidation state endows SnO2 with high conductivity of 211.42 S/cm by increasing its carrier concentration to the level of 3.02 × 10−20 cm−3. At a rate of 20C (about 30 A g−1), discharge capacity of (Sn, Nb)O2 with Nb content of 6 at. % can still remain 658 mA h g−1 and the specific capacity of NTO6 sample nearly got back to its original capacity when the rate returned back to 0.1C, maintaining at 986 mA h g−1 after 90 cycles. During the electrochemical cycling, the strong interplay of Nb dopant with host SnO2 was verified. Nb with an optimized content of 6 at.% can suppress the allotropy transformation from β to α - tin and sustain a capacity of 982.7 mA h g−1 till to 200 cycles. At the same time, Nb doped amorphous SnO2 crystallized into rutile structure, which would help to release stress during electrochemical reaction. The improved cycling performance is closely related with a persistence of Nb+5 valence, which will help to keep high conductivity of the host SnO2 materials. As a result, NTO6 remained crack-free, with a low electrical impedance within 200 cycles.

To construct a lithiophilic-lithiophobic gradient collector has been regarded as an effective strategy to address the challenge of lithium dendrite growth in Li metal anode. However, it was also found that the uneven stress accumulation, induced by the directional deposition, would cause fatigue-like failure in the gradient structure. In this work, a hybrid carbon nano fiber (CNF) structure, consisting of a gradient nitrogen doping CNF layer and a Cu doped CNF layer, was fabricated. The Cu-decorated carbon nanofibers not only provide a deposits-free (lithiophilic) surface, but also act as “reinforcing rib” to resist the fatigue stress. The unique hybrid structure delivered a high Coulomb efficiency and resistance to repeat stress application.

Transmission electron microscopy and energy dispersive X-ray spectroscopy have been used for crystallographic and compositional characterization of nano-precipitates distributed within the α-Zr matrix of the ZIRLO alloy. Intermetallic nano-particles with the C14 Laves-phase structure were found to be the dominant precipitate phase typically larger than 60 nm in sizes, which is assigned to the Zr(Fe,Nb)2 formula with Fe and Nb being mixed on the second sublattice sites in the bracket. Stacking faults were also observed in the ternary Laves phase, together with dislocations presenting on prism planes of the matrix solid solution. Besides, some fine spherical β-Nb particles about 30 nm in size were also found to precipitate within the α-Zr grains, with the α/β interface being crystallographically coherent.

Nickel phosphide (Ni3P) is a promising anode material for lithium-ion batteries owing to its high specific capacity, though significant improvement in its cycling stability is highly desired. Here we propose an effective and low-cost solution via a three-dimensional construction of porous NiO covered Ni3P films over a substrate of Ni foam, through electroless plating of P-rich Ni3P and subsequent in situ oxidation in air. The in situ oxidation of P-rich Ni3P resulted in the formation of nano porous NiO capping layer. Remarkable enhancement in the cycling stability of such a composite anode was thus realized. The initial discharge capacity for a CR2016-type coin cell was as high as 920 mA h g−1, and there was still a reversible capacity of 550 mA h g−1 after 60 cycles at a current density of 38.8 mA g−1. The presence of porous NiO capping layer changed the lithiation path and significantly improved the cycling performance. The decreased resistance in charge transport due to the existence of adequate channels for Li ions diffusion also enhanced rate performance. A pristine Ni3P films was researched as a comparison.

A LiNi

Monolayer MoTe

The corrosion behavior of Zr alloys was affected by second phases, especially by those containing Fe and Nb. Ti 2 Ni-type (Zr,Nb) 2 Fe compound was melted and exposed to H 2 O 2 water solution at 320 °C and 16.4 MPa for 60 h. The oxide layer was analyzed by X-ray diffraction and high-resolution transmission electron microscope (HRTEM). The formation of nano-crystalline tetragonal ZrO 2 (Fe-rich area) and amorphous ZrO 2 (Fe-deficient area) was observed. HRTEM analysis identified α-Fe could stabilize tetragonal ZrO 2 due to the epitaxial growth. ZrxFeyNb alloys with different iron were melted and corroded similarly. The result was consistent with the proposed mechanism.

A novel strategy was employed to introduce a carbon layer on Si particle to overcome the intrinsic poor electrical conductivity and significant volume change. The carbon layer was fabricated by forming polyphosphazene coating through a facile precipitation polymerization method, followed by carbonization. As a result of formation of core-shell structure, the Si anode exhibited improved cycling stability (740 mA h/g remained after 100 cycles) and rate capability (300 mA h/g at a rate 2C). In addition, 99% coulombic efficiency was remained after 100 cycles.

An important aspect of materials phenomena during the service of structural Zr alloys for nuclear cladding components is associated with hydrogen picking, which leads to the formation of δ-hydrides ZrHx (x = 1.55 or 1.66), the structural evolution of which is essential to the mechanical stability of the cladding components. In this work, we report the formation of δ-hydrides due to accidental hydrogen pickup, using high-resolution transmission electron microscopy (HRTEM). The results showed that the habit plane for relatively large δ-hydrides was (0001)α, with the plate morphology. The morphology for regions with populous nano-sized hydrides is irregularly blocky, albeit being of the same orientation relationship between hydrides and matrix. Such remarkable morphological change is associated with multi-nucleation and twinning in the hydrides crystals in the nano-scale.

The crystallographic characterization and defect structure of precipitates plays a key role in the properties of Zr alloys. The precipitates in Zircaloy-4 alloy are studied in this work. The Zr-Fe-Cr particles are identified as the dominant precipitates at room temperature with C14 or C15 type Laves structure. The Fe/Cr ratio of C15 type Zr-Fe-Cr phase is slightly lower than that of C14 type phase. The {0 0 0 1} stacking faults in C14 phase is observed and analyzed for the first time. Some new orientation relationships of C14 and C15 phases with α-Zr are identified.

Multilayer structure came into focus as a potential material in nuclear environment due to the special interface effect. Here, we studied the stability and chemical evolution of sputtered Zr/Si multilayer during annealing at 600 °C and 800 °C in air to explore its potential application as protective coating for nuclear materials. At 600 °C after 20 h oxidation, only the top Zr layer was oxidized and the diffusion of Si into the buried Zr layers contributed to the formation of Zr3Si compound layer uniformly. At 800 °C, the first Zr layer and Si layer were oxidized into m-ZrO2 and amorphous SiO2 layer, respectively. Underneath these oxide capping layers, the Zr Si compound layers near surface transformed into Zr-rich silicate layers with prolonged oxidation time. The continuous incorporation of Si into silicate layer triggered a reduction reaction to form Si-rich ZrSi2. Then, some silicon particles were formed through the de-alloying process of ZrSi2 and kept coherent interface with ZrSi2. These compounds were in situ formed in the original layer position, which maintained the multi-interface character. With further oxidation, this ZrSi2&Si layer was finally oxidized with self-healing ability.

High-quality graphene and graphene-based composites with optimized conductivity and surface chemistry state are crucial to the practical application in electrochemical energy storage and conversion systems. Here, we first propose a facile and general “prereduction-microwave” strategy to repair the lattice defects of reduced graphene oxides composites just in a few seconds, particularly, which has been successfully carried out on rGO/MoS2 composite previously synthesized through the hydrothermal method. This post repaired strategy not only can effectively improve the conductivity of graphene framework, but also well preserve the structural properties of graphene-based composites. Therefore, the optimized rGO/MoS2 composite achieves improved conductivity, good wettability, short ion diffusion length and excellent structural stability compared to the untreated rGO/MoS2 composite, which presents desirable capacity of 734 mAh g−1 for 200 cycles at 0.5 A g−1 and 335 mAh g−1 for 100 cycles at 1 A g−1 for lithium ion and sodium ion storage, respectively. This method will further promote the development of graphene-based materials for efficient energy storage and conversion.

Different carbon networks have been routinely used to modify Li anodes, which results in uniform nucleation on carbon materials. However, less attention is paid to the etching behavior of the Li metal under a modification layer. In this work, a failure analysis of a Li anode modified by an N-doped carbon nanofiber (CNF) demonstrates that pitting of the Li substrate is related to the final polarization of anode after relatively long cycling. A new approach is aimed at further improving the stability of a Li anode for long-period plating/stripping. The “two-pronged approach” combines a superficial SnOx decoration on the CNF and a plate-shell of Sn on the Li substrate that improves the electrochemical stability of Li. The superficial SnOx particles on the CNF induces the uniform deposition of Li on the CNF surface via a superficial alloying effect. The in situ formation of Li13Sn5 induces planar etching/growth of the Li substrate that improves the areal current density by two orders of magnitude. The “two-pronged approach” modified cells shows reduced polarization under a current density of 3 mA/cm2 and 5 mA/cm2 for 900 and 600 cycles, respectively. The “two-pronged approach” is also demonstrated by a full battery assembly with LiFePO4.

C14 Laves phase Zr(Fe,Nb)2 was fabricated and oxidized in a subcritical environment. Electron energy loss spectroscopy was used to study the migration and chemical state evolution of the elements. The oxidation process was accompanied by the formation of multilayered oxide scale, consisting of a crystalline oxide layer, amorphous oxide layer (Fe-poor) and Zr-Nb-Fe-O amorphous layer. The formation of closely bonded, semi-free and metallic iron species as well as the out diffusion of Fe contribute to the multilayered structure growth. The amorphization of the C14 phase occurred with the incorporation of oxygen, which preferentially bonded with Zr and Nb.

Surface treatment is of particular interest to slow down the in vitro degradation of Mg-based implants. In this work, micro arc oxidation (MAO) coating was fabricated on Mg–Zn–Ca alloy which has been developed by our group especially for the application of bio-implants. Evident improvement in corrosion resistance was obtained although the MAO coating was porous. In order to further diminish the contact with SBF, a composite coating was prepared by introducing a TiO 2 layer by liquid phase deposition (LPD) method on the MAO pre-treated alloy. The coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results of the potentiodynamic polarization experiments showed that, compared with the bare alloy, the corrosion potential of TiO 2 /MAO/alloy increased from −1.771 to −1.607 V. At the same time, the corrosion current density decreased from 1.43 × 10 −4 A cm −2 to 5.69 × 10 −7 A cm −2 . The improvement of degradation resistance in SBF was ascribed to both barrier effect and enhanced interface condition. The OH-terminated MAO layer surface can make the TiO 2 layer anchor tightly on the MOA surface. The chemical bonding of composite layer induced by Mg 2+ cations bridges was also analyzed.

Monolayer MoTe2 , with the narrowest direct bandgap of ≈1.1 eV among Mo- and W-based transition metal dichalcogenides, has attracted increasing attention as a promising candidate for applications in novel near-infrared electronics and optoelectronics. Realizing 2D lateral growth is an essential prerequisite for uniform thickness and property control over the large scale, while it is not successful yet. Here, layer-by-layer growth of 2 in. wafer-scale continuous monolayer 2H-MoTe2 films on inert SiO2 dielectrics by molecular beam epitaxy is reported. A single-step Mo-flux controlled nucleation and growth process is developed to suppress island growth. Atomically flat 2H-MoTe2 with 100% monolayer coverage is successfully grown on inert 2 in. SiO2 /Si wafer, which exhibits highly uniform in-plane structural continuity and excellent phonon-limited carrier transport behavior. The dynamics-controlled growth recipe is also extended to fabricate continuous monolayer 2H-MoTe2 on atomic-layer-deposited Al2 O3 dielectric. With the breakthrough in growth of wafer-scale continuous 2H-MoTe2 monolayers on device compatible dielectrics, batch fabrication of high-mobility monolayer 2H-MoTe2 field-effect transistors and the three-level integration of vertically stacked monolayer 2H-MoTe2 transistor arrays for 3D circuitry are successfully demonstrated. This work provides novel insights into the scalable synthesis of monolayer 2H-MoTe2 films on universal substrates and paves the way for the ultimate miniaturization of electronics.