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Lithium-ion batteries (LIBs) possessing high energy densities are driven by the growing demands of electric vehicles (EVs) and hybrid electric vehicles (HEVs). One of the most effective strategies to improve the energy density of LIBs is to enlarge the charge cut-off voltage via a lithium salt additive for the conventional electrolyte system. Herein, lithium difluorophosphate (LIDFP) is employed to optimize and reconstruct the composition of the structure and interface for both cathode and anode, which can effectively restrain the oxidation decomposition of electrolyte as well as refrain the dissolve out of transition metals. The LiNi0.8Co0.1Mn0.1O2 (LNCM811)/graphite pouch cell with 1 wt% LIDFP in electrolyte delivers a discharge capacity retention of 91.3% at a high voltage of 4.4 V over 100 cycles, which is higher than the 82.0% of that without LIDFP additive. Additionally, the remaining capacity of LNCM811/C battery with 1 wt% LIDFP additive which is left at 60 °C for 14 days is 85.2%, and the recovery capacity is 93.3%. The LIDFP-containing electrolyte demonstrates a great application future for the LiBs operating under the high-voltage condition and high-temperature storage performance.

Developing highly efficient, environmentally friendly and cost-effective electrocatalysts for oxygen reduction reactions is crucial for electrochemical energy conversion devices such as metal/air batteries and fuel cells. In this regard, metal-free porous carbons with their high activity, good stability and low cost show promising properties as a candidate for replacing expensive Pt-based electrocatalysts. However, it remains a major challenge to establish a template-free and green method for the synthesis of highly active metal-free carbon materials with outstanding performance over a wide pH range. In this paper, a controllable and scalable method to synthesize porous N-doped carbon nano-foams with interconnected bubble-like structures is presented. These as-prepared N-doped carbon catalysts, which were obtained by spray pyrolization and the subsequent heat treatment in the presence of NH3, possess activities which are well comparable to the commercial Pt/C. In addition, systematic electrochemical analyses were performed with a detailed explanation of the pore formation induced by the activation of Zn and NH3. In brief, this work is of great importance for the development of relevant electrochemical energy devices, particularly fuel cells and metal–air batteries.

Chemical short-range ordering (CSRO) or demixing in solid solution high entropy alloys (HEAs) is a fundamental issue yet to be fully understood. In this work, we first developed a generalized quasi-chemical solid solution model that enables quantitative computation of the local chemical ordering or demixing in solid solution HEAs. After that, we performed synchrotron diffraction experiments, extensive Reverse Monte Carlo (RMC) simulations, and first principles calculations on the CoCrFeNi model alloy to study the development of local chemical environments after long time thermal annealing. The outcome of the combined research demonstrates that the development of local chemical ordering or demixing in CoCrFeNi is not only affected by the heat of mixing between dislike atoms but also coupled with local lattice distortion.

In face-centered-cubic (fcc) metals, the evolution of Shockley partial dislocations under stress is known to play an important role in plastic deformation. The simulations of the dislocation evolutions, including dislocation dissociation, nucleation and recombination, under applied stress are presented using a phase field dislocation dynamics model that incorporates the γ surface of various fcc metals. As expected, the separation of the leading and trailing partials, termed the equilibrium stacking fault width (SFW), is governed by the details of the γ surface and the external loading conditions. Two important critical stresses, defined as the singular stress and the nucleation stress, are found to determine the stress-dependent evolution mechanism. As a general rule, the SFW increases with the applied stress and diverges when the applied stress exceeds the singular stress. A spontaneous nucleation of partial dislocation loops within the stacking fault (SF) occurs when the applied stress exceeds the nucleation stress. In particular, a new stress-size-dependent nucleation mechanism is observed in the simulations in the case where the singular stress is greater than the nucleation stress for a fcc metal: the nesting loop or nesting dipole can remain in the metastable state without any nucleation even the applied stress is twice as large as the nucleation stress.

A theoretical model is suggested to describe the dislocation-mediated mechanisms for the nucleation and growth of nanoscale deformation twins in hexagonal-close-packed materials. In the framework of the model, the nanoscale deformation twins nucleate and grow through the glide of glissile Shockley partial dislocations which are generated due to the nonplanar dissociation of the leading dislocation in a pile-up of 〈a〉 slip dislocations on the basal plane. Here, the pile-up of 〈a〉 dislocations on the basal plane was produced by preceding plastic deformation processes. The energy and stress conditions of the nanoscale deformation twin nucleation and growth through the dislocation-mediated mechanisms are calculated and discussed in detail. The results indicate that, when the pre-existent pile-up on the basal plane is 10–5, the nanoscale deformation { 1 ¯ 0 1 2 } twin nucleation stress is about 466.97–519.51 MPa. If take the shear stress applied to the pre-existent dislocation pile-up into account, the results are consistent with the experimental and molecular dynamic simulation results in literature. Besides, the twin is connected to grain boundary, and the longitudinal section of the twin is an approximately rectangular shape.

Stainless steel contains the elements Fe, Ni, Cr and Mn, which are known as active centers of oxygen evolution reaction (OER) catalysts. The high conductivity of stainless steel also makes it an ideal substrate for OER. These facts imply that stainless steel should be a suitable candidate as an OER electrode. Here, we report a simple solution treatment approach that enables stainless steel to be an efficient and stable OER electrode. It was found that a uniform brown film with highly rippled sheet structure could be in situ grown on stainless steel at room temperature by immersing it in an alkaline oxidant solution containing NaOH and (NH4)2S2O8. The composition of the brown film was found to include Fe(Ni)OOH by Raman and X-ray photoelectron spectroscopy (XPS) analyses. In 1 M KOH electrolyte, the prepared OER electrode exhibited good electrocatalytic performance with a relatively low overpotential of 300 mV at a benchmark current density of 10 mA/cm2 and a small Tafel slope of 34 mV/decade. Moreover, this OER electrode showed excellent long-term stability. This work highlights the possibility of potentially converting accessible materials into useful catalysts through simple chemical treatments.

Lithium-sulfur (Li S) batteries have been considering as a very promising energy storage system since their high theoretical specific capacity and energy density. Nevertheless, the practical commercialization of Li S batteries is hindered by their poor cycle stability and fast capacity fading. Herein, a carbonized bacterial cellulose/titania (CBC/TiO 2 ) modified separator is designed to restrain the shuttle effect of Li S cells with its strong physical and chemical adsorption of polysulfides. Cells with CBC/TiO 2 modified separator show an initial discharge capacity of 1314 mAh g − 1 at 0.2C, and the capacity retention is 1048.5 mAh g − 1 after 50 cycles. A discharge capacity of 475 mAh g − 1 is obtained after 250 cycles at 2C. And during the rate test, Li S cells can deliver a discharge capacity of 537.1 mAh g − 1 at 2C. The outstanding electrochemical performance of Li S cells with CBC/TiO 2 modified separator shows a new approach for the application of Li S batteries.

The a 0 / 2 〈 111 〉 screw dislocation glides through the nucleation and propagation of the kink-pair which dominates the plastic deformation of the BCC iron. A continuum model and the corresponding numerical methods are developed to investigate the kink mechanism on an arbitrary shape Peierls potential and subject to an external stress field. This model gives a link between the Landau theory of phase transitions and the line tension theory of string models. The order parameter is associated with the screw dislocation in BCC iron for describing the relative slip between adjacent Peierls valley. The kink configurations on the different Peierls potentials, such as the sinusoidal, Eshelby, anti-parabolic and camel-hump potential, are derived. By considering the motion of the screw dislocation on a 2-D Peierls potential surface, the 3-D saddle-point configuration of a non-planar kink-pair is obtained. The configuration is directly related to the details of the 2-D potential surface and it changes along with the applied stress tensor. A parameterized constitutive equation is derived for describing the temperature dependence of the flow stress which is compared with the experimental data from literature. The twinning/anti-twinning (T/AT) asymmetry and the tension-compression (T/C) asymmetry are reproduced in the model. The results rule out the possibility that the non-Schmid plasticity of the BCC iron is ascribed to split configuration.

The alumina contains plenty of Li2O and K2O as a result of using low-grade bauxite in China. Thus, LiF and KF will be enriched in the electrolytes with the operation of the cell, so that the composition and physicochemical properties of electrolytes have been changed. The effects of LiF, KF, and CR on the liquidus temperature of electrolytes based on the xNaF·AlF3-5 wt pct CaF2-2.5 wt pct Al2O3-0.5 wt pct MgF2 system have been investigated in this study. The results show that the liquidus temperature decreases by 5.13 K to 10.74 K (5.13 °C to 10.74 °C) per 1 wt pct addition of LiF and that the liquidus temperature decreases by 1.63 K to 3.8 K (1.63 °C to 3.8 °C) with per 1 wt pct addition of KF. When adding LiF and KF together, it has the interplay between LiF and KF. Under different electrolyte systems, the interplay between LiF and KF is complex. The effect of CR on liquidus temperature has been related to the concentration of LiF and KF.

MgAl 2 O 4 MgAlON materials as potential candidate sidewalls were prepared by using AlN, MgO, Al 2 O 3 , and nanosized MgAl 2 O 4 powder as starting materials. The reaction sintering of the MgAl 2 O 4 MgAlON materials was investigated by means of X-ray diffraction and scanning electron microscope. All the specimens were corroded in a Na 3 AlF 6 AlF 3 CaF 2 Al 2 O 3 bath to assess the electrolyte corrosion resistance. The results show that reaction sintering occurs in the MgAl 2 O 4 MgO Al 2 O 3 AlN system at 1830 °C and 5 MPa in flowing nitrogen for 5 h. The MgAl 2 O 4 MgAlON specimens are obtained and have high bulk density. The flexural strength increases from 202 ± 6 MPa to 248 ± 8 MPa and the Vickers hardness increases from 9.5 ± 0.2 GPa to 12.6 ± 0.4 GPa with increasing MgAlON content from 10 wt% to 40 wt%. The MgAl 2 O 4 MgAlON materials exhibit a good corrosion resistance to the Na 3 AlF 6 AlF 3 CaF 2 Al 2 O 3 bath owing to their high-density and the formation of the composite spinel in the specimens. The corrosion mechanisms of MgAl 2 O 4 MgAlON composites in molten electrolyte are mainly proposed by the dissolution of MgAl 2 O 4 and the diffusion of fluoride. Corrosion kinetic obeys a nearly parabolic law and the corrosion rate decreases with increasing MgAlON content.

The Cu 2 ZnSnS 4 thin film was prepared by a facile solution method without vacuum environment and toxic substance. The formation mechanism of the film was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. Through cyclic voltammetry and photo-electricity tests, the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitized solar cell was also studied. The results show that the mixed precursor solution mainly consists of Cu 2 SnS 3 nanoparticles and Zn ions. After 550 °C annealing process on the precursor film prepared from the mixed solution, Cu 2 ZnSnS 4 thin film is obtained. Besides, it is found that the prepared Cu 2 ZnSnS 4 thin film has the electrocatalytic activity toward the redox reaction of I 3 − /I − and the dye-sensitized solar cell with the prepared Cu 2 ZnSnS 4 thin film as the counter electrode achieves the efficiency of 1.09%.

Nitrogen-containing hollow carbon microspheres (NHCSs) are prepared by a modified template method in the presence of resorcinol/formaldehyde as carbon precursors and ethylenediamine (EDA) as both a base catalyst and nitrogen precursor. The NHCSs are used as anode materials for sodium-ion batteries, showing a superior reversible discharge capacity of 334 mAh g−1 after 100 cycles at 50 mA g−1. A high reversible discharge capacity of 114 mAh g−1 can also be obtained even at an extremely high current density of 10 A g−1. Moreover, excellent long-term cycling stability (>1200 cycles) is also observed even at 500 mA g−1. The results show that the NHCS electrode exhibits excellent electrochemical performance (superior reversible capacity, high rate capability, and long-term cycling stability). The excellent performance of NHCS electrode is most likely attributed to the unique nitrogen-containing hollow carbon structure. Furthermore, this study provides a novel route to produce NHCSs, which may find application in other fields.

The precipitate transformation from NiAl-type to Ni 2 AlMn-type and its influence on the mechanical properties of the Fe–5Ni–1Al− x Mn ( x = 0, 1, 3, and 5 wt.%) alloys were studied thoroughly through a combination of three-dimensional atom probe tomography (APT), first-principles calculations and mechanical tests. APT reveals the precipitation of NiAl-type nanoparticles in the 0-3Mn alloys and the co-precipitation of fine NiAl-type and coarse Ni 2 AlMn-type nanoparticles in the 5Mn alloy, in which the Ni 2 AlMn-type nanoparticles are formed as a result of the coarsening of the NiAl-type ones. The first-principles calculations indicate that the Ni 2 AlMn-type nanoparticles are energetically more favorable than the NiAl-type ones, but their nucleation and growth kinetics are relatively slow, resulting in the initial precipitation of the NiAl-type nanoparticles and the later precipitate transformation from NiAl-type to Ni 2 AlMn-type. A quantitative analysis of the strengthening mechanism reveals that although the Ni 2 AlMn-type nanoparticles have a higher strengthening efficiency than the NiAl-type ones, they make a minor contribution to the total strengthening effects due mainly to their small number density. In addition, the Ni 2 AlMn-type nanoparticles with a composition consistent with that of the Heusler phase are likely to promote the brittle cleavage and intergranular fracture of the 5Mn alloy, resulting in a significant decrease of the alloy ductility.

Alumina (Al2O3)-magnesium aluminate (MgAl2O4) composite was prepared from powders of magnesia (MgO) and Al2O3 by pressureless sintering. Phase compositions and properties of the Al2O3-MgAl2O4 composite were studied by adding different MgO contents as additive. Sintered products were subsequently characterized in terms of phase and microstructure analysis, densification study and compressive strength test. The results show that introduction of MgO is beneficial in forming MgAl2O4 reinforcement phase by solid state reaction between Al2O3 and MgO. Average particle size of Al2O3-MgAl2O4 composite decreases gradually with the increase of MgO content. Bulk density of the composite decreases from 2.48 to 2.40 g.cm–3 with the addition of MgO from 2 to 10 wt%, whereas compressive strength increases from 13 to 40 MPa. Reduction of particle size and the increase of MgAl2O4 bonding phase have resulted in increase of compressive strength of the Al2O3-MgAl2O4 composite.

Stainless steel fiber felts are important porous stainless steel products for a variety of industry applications. A systematic study of the sintering of 28-µm stainless steel fibers has been conducted for the first time, assisted with synchrotron radiation experiments to understand the evolution of the sintered joints. The critical sintering conditions for the formation of bamboo-like grain structures in the fiber ligaments were identified. The evolution of the number density of the sintered joints and the average sintered neck radius during sintering was assessed based on synchrotron radiation experiments. The optimum sintering condition for the fabrication of high strength and ductile 28-µm-diameter stainless steel fiber felts was determined to be sintering at 1000°C for 900 s. Sintering under this optimum condition increased the tensile strength of the as-sintered stainless steel fiber felts by 50% compared to conventional sintering (1200°C for 7200 s), in addition to much reduced sintering cycle and energy consumption.

1,1,2,2-Tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFTFE) was added to a solvate ionic liquid (SIL) based on glyme-lithium salt as a support solvent. The fluorinated ether improves cycle and rate capability of Li–S cells. The key role that TFTFE played in the cell system with SIL is an ionic conduction-enhancing ingredient, especially for high-rate cycle environment.

Solid polymer electrolyte (SPE)-based lithium sulfur battery offers high energy and safety for new energy vehicles and storage. However, the low room temperature ionic conductivity of the existing SPE limits the battery performance. Herein, a novel SPE film using food grade starch as a host was fabricated. This electrolyte provides exceptional lithium ion transportability with an ionic conductivity of 3.39 × 10−4 S cm−1 and lithium ion transference number of 0.80 at 25 °C. The application potential of this starch hosted electrolyte was demonstrated by all-solid-state lithium sulfur battery systems presenting the initial discharge capacity of 1442 mA h g−1, an average discharge capacity of 864 ± 16 mA h g−1 at 0.1 C for 100 cycles, 562 ± 118 mA h g−1 at 0.5 C for 1000 cycles at room temperature, and 388 ± 138 mA h g−1 for 2000 cycles at 2 C and 45 °C. This opens a bright route towards realizing energy power and safety with low cost and high sustainability.

Primary and rechargeable zinc/air batteries could be the next generation of energy storage devices because of their high power density and safety. The activity and durability of the catalyst play an important role in enhancing the electrochemical performance of the battery. Herein, Ni–Co@N-doped porous carbon (NC@NPC) core–shell microspheres are proposed as a bifunctional catalyst which exhibits significantly enhanced onset oxygen reduction reaction (ORR) potential (−0.19 V vs. Ag/AgCl) and oxygen evolution reaction (OER) current density (16.2 mA cm−2 at 0.8 V vs. Ag/AgCl) due to the synergy of metallic Ni and Co. Namely, practical rechargeable NC@NPC loaded zinc/air battery testing using oxygen in air demonstrates desirable discharge voltages at current densities up to 80 mA cm−2. Besides, steady charge and discharge voltages at the current density of 10 mA cm−2 are obtained over 60 cycles.

Three kinds of Bi–Se nanocrystals (Bi2Se3, Bi8Se9 and Bi1.007Se0.993) have been synthesized via a hot-injection approach. The colloid morphology, from hexagonal to octahedron, strongly depends on the injection temperature. The growth mechanism of Bi–Se nanocrystals is revealed here. A higher temperature could cause the reduction reaction from Bi3+ to Bi, and accelerate the reaction speed of Bi–Se, thus causing a difference of monomer concentration in bulk solution, which impacts the shapes of bismuth selenide nanocrystals as well as the composition. The three Bi–Se nanocrystals also show different optical and photoelectrocatalyst performance.

The thickening mechanism of the deformation twinning (DT) has been frequently studied in numerous researches and the transverse propagation of that is beginning to trigger the attention of scholars. Recently, some researchers report that the twin front of { 10 1 ¯ 2 } mode of Magnesium is composed of a conjugate twin plane and prismatic/basal (PB) planes, and the combined mobility of these planes rule the overall kinetics of twin propagation. Focusing on that, a continuum phase field model is proposed to investigate the equilibrium shape of tensile twins and the kinetics of the twin front. A new form of surface free energy is introduced in this model for the purpose of describing the orientation-dependent properties of twin boundaries. The simulations well reproduce the PB interfaces and the results indicate that the anisotropic surface energy plays a dominant role in forming the irregular facets on the twin front. A generalized energy-momentum tensor is derived and analyzed for shear loading in order to investigate the equilibrium and mobility of twin boundaries, and the simulations show that the configurational forces distributed on the PB interfaces are smaller than that on the other twin planes, which implies that the growth of twin is beneficial for the formation of PB interfaces. The simulations also indicate that the anisotropic twin boundary energy is not responsible for the large aspect ratio nature of twins, which may be governed by the competition between thickening mechanism and transverse propagation mechanism of the DT.

Porous n-type Fe2V4O13 films on FTO substrates were prepared by a simplified successive ion layer adsorption and reaction method and characterized as photoelectrodes for photoelectrochemical (PEC) water oxidation. Synthesis parameters such as film thickness and annealing temperatures and durations were investigated to optimize the PEC performance. A band gap of ∼2.3 eV and a flat band potential of 0.5 V vs. RHE make Fe2V4O13 a promising photoanode material. Water oxidation was kinetically limited at the surface of Fe2V4O13 film as confirmed by tests in electrolyte with a hole scavenger (Na2SO3). Improved PEC performance was achieved by Mo and W doping because of enhanced carrier densities. The best performance was obtained by 2.5% W-doped Fe2V4O13 films (actual 0.8% W-doped), which efficiently oxidize water to O2via photogenerated holes as confirmed by oxygen evolution measurements. Moreover, the Fe2V4O13 photoanode displayed very stable photocurrent under illumination. Due to the suitable band gap and valence band position, Fe2V4O13 is a promising photoanode for solar water splitting. Co-catalyst loading and doping optimization are identified as routes to improve this material's performance further.

A triPEG-boron based solid polymer electrolyte (SPE) membrane is fabricated for all-solid-state lithium ion batteries. With an ether oxygen (EO):LiN(SO2CF3)2 (LiTFSI) molar ratio of 25:1, this electrolyte membrane has ionic conductivities of 2.95 × 10−5 S cm−1 and 1.28 × 10−3 S cm−1, and electrochemical decomposition potentials of 5.23 V and 4.88 V, respectively at 25 °C and 120 °C. The all-solid-state LiFePO4/SPE/Li batteries show high cycling performance in the temperature range of 25–140 °C. At 25 °C and 0.3C, a discharge capacity of 84 mA h g−1 is obtained at the 200th charge–discharge cycle with approximately 100% coulombic efficiency. The batteries also work well at 140 °C and 3C, delivering a discharge capacity of 146 mA h g−1 initially and 113 mA h g−1 after 200 cycles. These results show that this kind of all-solid-state lithium ion battery has a wider working temperature range than conventional liquid electrolyte lithium ion batteries, indicating their suitability for use in fields with high safety requirements.

Surface tailored Ga Au loaded mesoporous silica nanoparticles are considered as an important nanomaterial for biomedical applications such as diagnosis and cancer treatment. In this study, we used Ga Au loaded mesoporous silica nanoparticles (Ga-Au@mSiO2) for the photothermal treatment of two prostate cancer cell lines. We systematically examined the nanocomposite form by various spectroscopic (UV–Vis, TGA and DTA) and electroscopic techniques (TEM and SEM including the elemental mapping analysis). After careful evaluation of the nanocomposite form, we performed cancer cell growth inhibition properties of the prostate cancer cell lines (DU145 and LNCaP). Also, we performed the photothermal effects of these nanocomposites on cell proliferation and apoptosis using different biochemical staining and flow cytometry. Our in vitro investigational datas are established Ga-Au@mSiO2 effectively exhibited and also with Ga-Au@mSiO2 + NIR the photothermal conversion therapy improved prostate cancer cells abolishing the prostate cancer cells. Interestingly, Ga-Au@mSiO2 + NIR was found to surpass the activity of Ga-Au@mSiO2 in all the cancer cells tested a topnotches. Hence, our current results demonstrated that surface tailored Ga Au loaded mesoporous silica nanoparticles significantly inhibited the growth of prostate cancer cell lines and shown prominent antitumor effect in vitro. Thus, our study suggests that Ga-Au@mSiO2 + NIR could be used as impending anticancer candidate for photothermal ablation of prostate cancer cells. Further examinations of the mechanism indicated that anticancer activity was accomplished by inducing apoptosis in cancer cells, which is suggesting that these Ga-Au@mSiO2 + NIR nanocomposite can be used as promising candidates for nursing care cancer therapy.

The corrosion and oxygen evolution behaviors of cast and rolled Pb–Ag–Nd anodes were investigated by metalloscopy, environmental scanning electron microscopy, X-ray diffraction analysis, and various electrochemical measurements. The rolled anode exhibits fewer interdendritic boundaries and a dispersed distribution of Pb–Ag eutectic mixtures and Nd-rich phases in its cross-section. This feature inhibits rapid interdendritic corrosion into the metallic substrate along the interdendritic boundary network. In addition, the anodic layer formed on the rolled anode is more stable toward the electrolyte than that formed on the cast anode, reducing the corrosion of the metallic substrate during current interruption. Hence, the rolled anode has a higher corrosion resistance than the cast anode. However, the rolled anode exhibits a slightly higher anodic potential than the cast anode after 72 h of galvanostatic polarization, consistent with the larger charge transfer resistance. This larger charge transfer resistance may result from the oxygen-evolution reactive sites being blocked by the adsorption of more intermediates and oxygen species at the anodic layer/electrolyte interfaces of the rolled anode than at the interfaces of cast anode.

Kesterite Cu 2 ZnSnS 4 (CZTS) thin films have been fabricated by an electrodeposition route via sulfurizing sequentially electrodeposited Cu–Zn and Cu–Sn stacked binary alloy layers. The CZTS films exhibit densely packed grains with only minor ZnS secondary phase. Photovoltaic device with the structure of ITO/i-ZnO/CdS/CZTS/Mo/Glass shows the highest power conversion efficiency of 3.67%. The limiting factors of the efficiency are the high series resistance and recombination rate. The ZnS phase, voids at the Mo/CZTS interface and high resistance MoS 2 layer have been considered to lead to high series resistance and thereby low J SC and FF.

Three dimensional molecular dynamics (MD) simulations are systematically carried out to reveal the mechanism of the crack healing at room temperature, in terms of the dislocation shielding and the atomic diffusion to control the crack closure, in a copper (Cu) plate suffering from a shear loading. The results show that the process of the crack healing is actualized through the dislocation emission at a crack tip accompanied with intrinsic stacking faults ribbon forming in the crack tip wake, the dislocation slipping in the matrix and the dislocation annihilation in the free surface. Dislocation included stress compressing the crack tip is examined from the MD simulations and the analytical models, and then the crack closes rapidly due to the assistance of the atomic diffusion induced by the thermal activation when the crack opening displacement is less than a threshold value. This phenomenon is very different from the previous results for the crack propagation under the external load applied because of the crack healing (advancing) largely dependent on the crystallographic orientations of crack and the directions of external loading. Furthermore, based on the energy characteristic and considering the crack size effect, a theoretical model is established to predict the relationships between the crack size and the shear stress which qualitatively agree well with that obtained in the MD simulations.

A novel bimodal porous carbon (BPC) with high surface area was prepared by a simple hydrothermal route and KOH activation process, and the Se–BPC composite was synthesized for lithium–selenium batteries by the melt-diffusion method. It is found that the elemental selenium was dispersed inside the pores of BPC based on the analyses. Electrochemical tests reveal that the Se–BPC composite has a large reversible capacity and high rate performance as cathode materials. The Se–BPC (45.1 wt.% Se) composite displays an initial discharge capacity of 552 mAh g − 1 and a reversible discharge capacity of 264 mAh g − 1 after 80 cycles at 1 C charge/discharge rate. In particular, the Se–BPC composite presents a durable cycling performance at high rate of 2 C. These outstanding electrochemical features of Se–BPC composite cathode should be attributed to the uniform BPC with high surface area and bimodal porous structure. The bimodal porous carbon would be a promising carbon matrix to develop high performance lithium–selenium batteries.

The anodic layer and oxygen evolution behavior of Pb–Ag–Nd alloy during pulse current polarization and constant current polarization in 160 g/L H 2 SO 4 solution was comparatively investigated by chronopotentiometry, SEM, XRD, EIS and Tafel techniques. The results show that the anodic layer on Pb–Ag–Nd alloy formed through pulse current polarization is more intact and presents fewer micro-holes than that formed through constant current polarization. This could be attributed to the low current density period, which works as a ‘recovery period’. During this period, the oxygen evolution reaction is less intense, which benefits the recovery of porous anodic layer. Pb–Ag–Nd anode also shows a lower anodic potential during pulse current polarization, which is in accordance with its smaller charge transfer resistance and smaller Tafel slope coefficient at high over-potential region. The lower anodic potential could be ascribed to the higher concentration of PbO 2 in the anodic layer, which promotes the formation of more reactive sites for the oxygen evolution reaction.

A novel highly ordered nitrogen-rich mesoporous carbon (HNMC) was prepared by pyrolysis of biomass waste (gelatin) and a simple template process, and sulfur–HNMC composite based on HNMC was synthesized for lithium–sulfur batteries by a melt-diffusion method. It is found that the elemental sulfur was homogeneously dispersed inside the meso-pores of HNMC based on the analyses. Electrochemical tests reveal that the sulfur–HNMC (53.3 wt% sulfur) composite shows high rate capability and long cycling stability as cathode materials. The sulfur–HNMC (53.3 wt% sulfur) composite cathode exhibits a high initial discharge capacity of 1209 mAh g −1 and retains as high as 600 mAh g −1 after 200 cycles at 1 C. Moreover, the cathode also presents a long term cycling stability up to 300 cycles even at 3 C. The results illustrate that the high rate capability and long term cycling stability of sulfur cathode can be enhanced significantly by encapsulating sulfur into the highly ordered nitrogen-rich mesoporous carbon nanostructure, and the HNMC nanostructure would be a promising carbon matrix for high-performance lithium–sulfur batteries.

Fluorinated ether of ethyl 1,1,2,2-tetrafluoroethyl ether (ETFE) was selected as electrolyte solvent for lithium/sulfur battery, and the influence of ETFE in electrolyte on cell properties was first investigated. The enhanced stability of electrolyte/anode interface and improved electrochemical performances (cycling, rate and self-discharging) of the Li/S cell are presented by using ETFE-containing electrolyte, especially for complete replacement of tetraethylene glycol dimethyl ether (TEGDME) by ETFE in combine with 1,3-dioxolane (DOL). It is found that ETFE plays a key role in modifying the surface composition and structure of the metallic Li, forming a strengthened protective film on the anode during cycling. Besides, ETFE is considered to decrease the dissolution of polysulfides in the electrolyte. These factors together restrict the contact and reaction between polysulfides and Li anode.

A (Cu,Ni)/(10NiO-NiFe2O4) cermet was tested as an inert anode for aluminum electrolysis in Na3AlF6-K3AlF6-AlF3 melt at 1173 K (900 °C), and its corrosion behavior was studied. The results show that the low-temperature Na3AlF6-K3AlF6-AlF3 bath is beneficial, improving the service conditions. With the combined effects of the electrolyte composition and the nascent oxygen during electrolysis, the metal phase (Cu,Ni) at the surface of anode will not be leached preferentially, but be transferred into the aluminates including FeAl2O4, NiAl2O4 and CuAl2O4. This is helpful for the anode to improve its corrosion resistance.

Earth abundant Cu2ZnSnS4 (CZTS) has triggered great attention in the field of low cost thin film solar cells. High-quality CZTS nanocrystals were synthesized by a facile solution method, with an average particle diameter about 12 nm and a direct band gap of 1.49 eV. And these nanocrystals were readily dispersed to form a colloidal ink, which was then used to prepare thin films by doctor blading approach. Effects of sulfurization temperature on those films’ composition, morphology and phase were studied. The obtained thin film, annealed under flow S/Ar atmosphere at 550 °C for 30 min, shows a dense smooth surface, a slightly Cu-poor and Zn-rich composition and the kesterite CZTS structure. Besides, this 550 °C annealed CZTS film was then fabricated into full photovoltaic device and a power conversion efficiency of 2.29 % has been achieved. Directions for further improvements have also been discussed and proposed.

Cu 2 FeSnSe 4 (CFTSe) nanocrystals have been synthesized by a hot-injection method. The structure of prepared CFTSe nanocrystals is determined by XRD, high resolution TEM image, and SAED pattern. The composition of the CFTSe nanocrystals is confirmed from the results of EDS and XPS. Results clearly prove the formation of CFTSe nanocrystals using the hot-injection method in this study. A band gap of 1.60±0.02 eV for CFTSe nanocrystals is obtained from the UV–vis–NIR data. Moreover, the corresponding CFTSe nanocrystals-film shows a clear photoresponse in photoelectrochemical measurement. Our work illustrates that CFTSe nanocrystals have potential application in the field of solar energy conversion.

In this paper, nano-lead-doped active carbon (nano-Pb/AC) composite with low hydrogen evolution current for lead-acid battery was prepared by ultrasonic-absorption and chemical-precipitate method. The nano-Pb/AC composite was characterized by SEM, EDS and TEM. The electrochemical characterizations are performed by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in a three-electrode system. Since intermediate adsorption is the rate-determining step, the hydrogen evolution reaction (HER) is markedly inhibited as the intermediate adsorption impedance of nano-Pb/AC increased. Meanwhile, the working potential of nano-Pb/AC is widened to the whole potential region of Pb negative plate (from −1.36 V to −0.86 V vs. Hg/HgSO4) in lead-acid battery. In addition, nano-Pb can improve the interfacial compatibility between AC and Pb paste, accordingly relieve the symptoms of carbon floatation. Finally, 2.0 V single-cell flooded lead-acid batteries with 1.0 wt.% nano-Pb/AC or 1.0 wt.% AC addition in negative active materials are assembled. The cell performances test results show that the 3 h rate capacity, quick charging performance, high current discharging performance and cycling performance of nano-Pb/AC modified battery are all improved compared with regular lead-acid battery and AC modified lead-acid battery.

Highly ordered iron oxide nanotubes with smooth and homogeneous wall were electrochemically synthesized by potentiostatic anodization of iron foil in an ethylene glycol based electrolyte containing NH 4 F and deionized water at 60 °C. A model was proposed to explain the formation mechanism. The effects of anodization conditions, such as potential, H 2 O concentration, NH 4 F concentration, temperature and thermal treatment, on morphology and structural features of the oxide layer were thoroughly investigated. It is shown that the current transient curve can be used as a tool to approximately predict the morphology and the formation of nanotube during the anodization of iron.