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[Display omitted] Typical LiNi x Co y Mn 1- x - y O 2 (NCM) layered oxides are a promising research area for high-energy–density cathode materials. However, they still suffer from structural disorder due to severe Li/Ni mixing caused by solid-state reactions at high temperatures (700–900 °C). To address these problems, most strategies focus on increasing the energy barrier of Ni2+ migration towards Li+ sites, such as doping or annealing in an O 2 -rich atmosphere. Herein, we report a new strategy of lowering processing temperature for effectively regulating Li/Ni mixing, achieved by hydrothermal ion exchange. The ion exchange can achieve a rapid substitution of Li+ ions for Na+ ions at relatively low temperatures (160–220 °C), allowing the NCM to maintain low Li/Ni mixing (<1%). Our ab initio calculations further demonstrate that the Ni2+ diffusion rate in ion-exchanged NCM523 at 200 °C is significantly slower in the order of 10−12 than that in NCM523 calcined at 900 °C, indicating that processing temperature is crucial to regulating Li/Ni mixing. That is, Li/Ni mixing of NCM523 materials is effectively regulated during ion exchange, further enhancing the structural stability and electrochemical performance. In addition, the universality of hydrothermal ion exchange was further proved by synthesizing NCM materials with good structural stability for different nickel contents (x = 0.5, 0.65, 0.7, 0.85). We anticipate that our ion-exchange strategy opens a new door towards regulating Li/Ni mixing by lowering processing temperature, enabling layered oxide materials with enhanced structural stability. [ABSTRACT FROM AUTHOR]

Layered oxide cathodes such as Ni‐rich ternary and Li‐rich layered cathode materials have been widely used for lithium‐ion batteries owing to their excellent Li+ transport properties, high energy density, and relatively low cost. However, such layered cathode materials synthesized by high‐temperature sintering face inherent issues such as low structural stability, irreversible migration of transition metal ions, and irreversible redox reactions of oxygen anions. To make a breakthrough from the perspective of material synthesis, a new ion‐exchange synthesis has emerged in recent years, which is a promising strategy for synthesis of Li‐ion cathodes. Herein, the fundamentals of ion‐exchange synthesis and their implications in layered oxide cathodes for lithium‐ion batteries is presented. Specifically, ion‐exchange synthesis and mechanisms of ion exchange are introduced in detail, followed by a discussion of the reduction of synthetic temperature, the synthesis of novel crystal structures, the inhibited migration of transition metal ions, the increased reversibility of anionic redox, and the optimized surface reconstruction. Finally, a summary and outlook is provided for ion‐exchange synthesis of layered oxide cathodes for lithium‐ion batteries. It is anticipated that this ion‐exchange synthesis will facilitate the commercialization of high‐performance cathode materials for next generation Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Highlights: [•] The initial hardening rate was reduced with external stress during aging. [•] Stress-aging can accelerate the precipitation of θ ′ but restrain that of Ω. [•] Prior deformation can also accelerate the precipitation of θ ′ but restrain that of Ω. [Copyright &y& Elsevier]

The creep behavior of Al–Cu–Mg–Ag alloy and its microstructural evolution during creep deformation were studied at 100–210°C with the external stress of 150–300MPa. The results show that both Ω and precipitate secondarily in the under-aged sample during the creeping process, resulting in the excellent creep-resistant property compared to the peak aged sample. The temperatures between 100 and 150°C have little affect on the creep curves of the alloy. The larger external stress led to the growth of the creep holes on the grain boundaries and the higher creep temperature led to the growth of the precipitations in the grains inner. They both result in the lower creep resistance of Al–Cu–Mg–Ag alloy. The steady creep rate increased with increasing creep temperature or external stress, which can be described by a constitutive equation with the creep deformation activation energy 102.00kJ/mol. [ABSTRACT FROM AUTHOR]

Highlights: [•] Compared with T7451 treated sample, RRA treated one exhibits enhanced fatigue crack growth resistance. [•] EBSD analysis showed crack growth behaviors within grains or grain boundary in both samples. [•] Examination of micro fractures and surfaces were performed with SEM in both samples. [ABSTRACT FROM AUTHOR]

• SnS particles anchored on the surface of Ti 3 C 2 nanosheets. • Ti 3 C 2 can effectively inhibit the volume expansion of SnS particles. • The obtained anode exhibits excellent cycle performance and structure stability. Tin sulfide (SnS) has been regarded as one of the most attractive anode materials for lithium-ion batteries (LIBs) because of its high specific capacity. However, its large volume expansion (>300%) and low electronic conductivity restrict its application. In this study, Sn2+ was anchored on Ti 3 C 2 nanosheets through electrostatic attraction, and Ti 3 C 2 @SnS@C was synthesized through a hydrothermal method. The obtained Ti 3 C 2 @SnS@C exhibits excellent rate performance and cycle performance and effectively serves as an anode material for LIBs. It has a stable capacity of 563.5 mAh/g after 420 cycles at 500 mA/g, and this value is much higher than that of commercially available anode materials. Ti 3 C 2 can also effectively inhibit the volume expansion of SnS particles. The volume expansion of Ti 3 C 2 @SnS@C electrode is only 56.8% after 420 cycles at 500 mA/g. This finding is much better than that of pure SnS@C electrode (209.3%). [ABSTRACT FROM AUTHOR]

Abstract: The thermal stability of Al–Cu–Mg–Ag alloy was tested by thermal exposure and creep performance. The results show that the under-aged Al–Cu–Mg–Ag alloy possessed better thermal stability compared to the peak-aged one, due to the secondary precipitations of the strengthening phases. The number of the precipitations in the under-aged sample increased and then decreased with increasing the thermal exposure or creep time while that of the peak-aged sample decreased gradually. The tensile strength of the under-aged sample increased and then decreased with increasing the thermal exposure time with a peak value of 524MPa after exposed for 20h, which was 19MPa higher than that of the peak-aged alloy. The steady creep rate of the under-aged sample was much lower and the creep-life was much longer to that of the peak-aged one, indicating that the under-aged sample possessed excellent creep resistance property at elevated temperatures. [Copyright &y& Elsevier]

Abstract: Influence of retrogression and re-aging treatment on the microstructure, strength, exfoliation corrosion, inter-granular corrosion and stress corrosion cracking of an Al–Zn–Mg–Cu alloy has been investigated by means of optical microscope (OM), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS). The results show that retrogression and re-aging treatment can increase the size and the distribution discontinuity of the grain boundary precipitates, and lead to the increase of the corrosion resistance without the loss of strength and ductility. In addition, the analysis of electrochemical impedance spectroscopy shows that retrogression and re-aging treatment can enhance the resistance to exfoliation corrosion. [Copyright &y& Elsevier]

Abstract: The effects of solution treatment on the microstructure and mechanical properties of Al–Cu–Mg–Ag alloy were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), differential scanning calorimeter (DSC), transmission electron microscopy (TEM) and tensile test, respectively. The results show that the mechanical property increases and then decreases with increasing the solution temperature. And the residual phases are dissolved into the matrix gradually, the number fraction of the precipitation and the size of recrystallized grains increase. Compared to the solution temperature, the solution holding time has less effect on the microstructure and the mechanical properties of Al–Cu–Mg–Ag alloy. The overburnt temperature of Al–Cu–Mg–Ag alloy is 525°C. The yield strength and the elongation get the best when the alloy is solution treated at 515°C for 1.5h, is 504MPa and 12.2% respectively. The fracture mechanism of the samples is ductile fracture. [Copyright &y& Elsevier]

Abstract: Based on the classical flow stress–dislocation density relation and kinetics of dynamic recrystallization (DRX), a model was developed to determine flow stress of magnesium alloy at hot deformation condition. The proposed model is capable of predicting the flow behavior of work hardening and dynamic recovery (DRV) region as well as the softening caused by DRX. To establish the model, the double-differentiation method was used to identify the critical strain for initiation of DRX, and the DRV parameter Ω was evaluated from the work-hardening behavior prior to critical strain. The net softening attributable to DRX was defined as the difference between the DRV and experimental curves, and Avrami equation was employed to represent this softening behavior. The flow stress curves of ZK60 magnesium alloy predicted by the developed model are in good agreement with experimental results, which confirms the validity of the model. [Copyright &y& Elsevier]

Abstract: The microstructure and mechanical properties of Al–Cu–Mg–(Ag)–Mn–Zr alloys were studied by means of tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that small additions of Ag to Al–Cu–Mg–Mn–Zr alloy can accelerate the hardening effect of the aged alloy and reduce the time to peak-aged. The mechanical properties can be improved both at room temperature and at elevated temperatures, which is attributed to the fine and uniform plate-like Ω precipitates. Meanwhile the ductility of the studied alloys remains at relatively high level. The major strengthening phases of the Ag-free alloy are θ′ and less S′, while that of Al–Cu–Mg–Mn–Zr alloy containing trace amounts of Ag are Ω and less θ′. [Copyright &y& Elsevier]

Abstract: The microstructure evolution in an Al–Cu–Mg–Ag heat-resisted alloy during homogenization was studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and differential scanning calorimeter (DSC). The results show that severe dendritic segregation exists in Al–Cu–Mg–Ag alloy ingot. There are many eutectic phases in grain boundary and the distribution of the main elements along interdendritic region varies periodically. The main secondary phase is θ-Al2Cu. By increasing the homogenization temperature or prolonging the holding time, the residual phases are dissolved into the matrix gradually, grain boundaries becomes sparse and all elements become more homogenized, which can be described by a constitutive equation in exponential function. The overburnt temperature of Al–Cu–Mg–Ag alloy is 510°C. And the proper homogenizing process is 500°C×16h, which is consistent with the results of homogenization kinetic analysis. [Copyright &y& Elsevier]

Abstract: The flow behavior of Al–Cu–Mg–Ag alloy and its microstructural evolution during hot compression deformation were studied by thermal simulation test. The flow stress increased with increasing the strain rate, and decreased with increasing the deforming temperature, which can be described by a constitutive equation in hyperbolic sine function with the hot deformation activation energy 196.27kJ/mol, and can also be described by a Zener–Hollomon parameter. The dynamic recrystallization only occurred at low Z values, which must be below or equal to a constant of 5.31×1013 s−1. With decreasing Z value, the elongated grains coarsed and the tendency of dynamic recrystallization enhanced. Correspondingly, the subgrain size increased and the dislocation density decreased. And the main soften mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization. [Copyright &y& Elsevier]

We melted five types of Al-Zn-Cu-Mg-Zr alloys and added 0.0, 0.1, 0.2, 0.3, and 0.5 (wt.%) of scandium. Its influence on the microstructure of alloys and their mechanical properties is studied with the help of optical transmission and scanning electron microscopes. An insignificant amount of scandium promoted the formation of Al3 (Sc, Zr) particles. These particles efficiently clean the microstructure, decelerate and preserve recrystallization, and fix dislocations and substructures. The strength of the alloys increases for high levels of plasticity. It is shown that the optimal properties of the alloys with 0.21% Sc are attained after holding in a solution for 40 min at 475°C and aging for 24 h at 120°C. The strength of the alloys increases mainly as a result of dispersion solidification and microstructural hardening with Al3 (Sc, Zr) particles. [ABSTRACT FROM AUTHOR]

Electrochemically converting greenhouse gases into high-value fuels/chemicals in solid oxide electrolysis cells (SOECs) offers significant socio-economic and environmental benefits, but its practical implementation has long been limited by sluggish reaction kinetics and poor long-term stability because of the absence of highly active and stable catalysts. Substantial effort has been devoted to addressing this issue, among which growing nano-socketed metal particles in situ on perovskites has achieved huge progress in electrosynthesizing high-value fuels from various greenhouse gases. A critical review on the principles and influential factors of in situ exsolution is needed, with an emphasis on discussing the latest advances on in situ exsolution of metal/alloy nanoparticles (NPs) and their associated applications for greenhouse gas conversion in various SOECs. This review focuses on the prospects and underlying challenges of in situ exsolution strategies and their application in future research. Topics include the thermodynamics and kinetics of exsolution, materials internal factors (composition, phase transformation, lattice strain, crystal facet orientation, and topotactic ion exchange), external environmental factors (temperature and heat-up time, atmospheric partial pressure, applied voltage, and other factors), and a survey of applications (CO 2 capture, H 2 production, CO 2 -H 2 O co-electrolysis, alkane reforming, and ammonia production). For Table of Contents Graphic Only. [Display omitted] • The principles of in situ exsolved metal particle from perovskite were discussed. • Various influencing factors of in situ exsolution over perovskite were reviewed. • Recent advances on electrosynthesizing high-value fuels were reviewed. • The challenges and perspectives of exsolution over perovskite were elaborated. [ABSTRACT FROM AUTHOR]

N ickle (Ni)-rich layered oxides as promising candidate of high-capacity cathode materials have aroused extensive concern primarily regarding their higher specific capacity. However, the major hurdle of Ni-rich cathodes (Ni content ≥0.7) is their poor cycling stability, which often suffers from the release of oxygen, structural degradation and increased impedance during cycling, especially at high voltage or high temperature. Herein, we demonstrated a feasible solid phase method for easy industrialization based on the Al3+/Zr4+ co-doping in LiNi 0.72 Co 0.05 Mn 0.23 O 2 (A X Z Y -NCM) single-crystal cathode. The optimized A 0.5 Z 0.5 -NCM single-crystal material exhibited greatly enhanced structural and thermal stability. XRD refinement results indicated that both Al3+ and Zr4+ were mainly located in transition metal (TM) sites, strengthening the layered structure through strong M-O bonds and inhibiting cation mixing. In-situ XRD revealed that the synergistic rivet effect of Al/Zr co-doping alleviates anisotropic lattice stress-strain during charge/discharge process. Accordingly, the A 0.5 Z 0.5 -NCM cathode can output a high initial capacity of 177.3 mAh g−1 at 1 C, and captured a more desirable capacity retention of 85.10 % than that of U-NCM (74.33 %) at 1 C over 200 cycles. Even at a high voltage of 4.5 V, its capacity retention can still reach 82.37 %, significantly surpassing the unmodified U-NCM (31.0 %). The above results demonstrated that well-designed dual doping is highly effective for strengthen structure stability and cycling performance of Ni-rich cathodes. [Display omitted] • Al/Zr doped LiNi 0.72 Co 0.05 Mn 0.23 O 2 are designed to reveal the synergistic effect of Al/Zr co-doping on boosting structural stability. • The optimized A 0.5 Z 0.5 -NCM achieves the superior thermal stability with their thermal runaway temperature (229.69 oC). • The A 0.5 Z 0.5 -NCM shows excellent cycling stability with 85.1% retention after 200 cycles at 2.8∼4.35 V. [ABSTRACT FROM AUTHOR]

In this study, the effects of different Sc + Zr compound addition on the tensile properties, impact toughness, stress corrosion cracking (SCC) properties, polarization curves, electrochemical impedance spectroscopy (EIS), and pitting corrosion (PC) of Al–Zn–Mg alloys are investigated. The results show that the Sc + Zr co-addition significantly inhibits the recrystallization behavior, refines the grain structure, and improves the tensile properties and impact toughness of the studied alloys. In fact, 0.43 wt% Sc + Zr-containing alloy achieves the maximum tensile properties, the tensile strength and yield strength are increased by 60.4 and 71.5 MPa, respectively. The impact toughness of 0.30 wt% Sc + Zr-containing alloy is 36.5 J/cm2, which is increased by 6.4 J/cm2. The Sc + Zr co-addition significantly reduces the SCC sensitivity, increases the charge transfer resistance, decreases the corrosion current density, and improves the PC resistance of Al–Zn–Mg alloys. The results of the strengthening model show that the main strength mechanism of Al–Zn–Mg alloys is precipitation strengthening of conventional η′ phases. The high toughness and corrosion resistance of alloys with Sc + Zr co-addition associated with the recrystallization resistance and the grain structures yielded by coherent Al3ScxZr1-x particles. [ABSTRACT FROM AUTHOR]

The strength and precipitates after T8-aging (second-step aging at 170 °C following first-step aging at 150 °C for 4 h after 6% predeformation) and grain structures of 1445 Al-Li alloy (Al-1.7Li-1.5Cu-0.9Mg-0.1Mn-0.1Zr-0.1Ag-0.1Ti-0.08Sc-0.07Ni) cold-rolled sheet were investigated. The main precipitates are δ′ (Al 3 Li) and S′ (Al 2 CuMg). It is critical that nano-sized Al 3 (Sc,Zr) dispersoids are formed, and the Cu-enriched and Sc-containing W phases (AlCuSc) are not found. Due to the strong pinning effect of the nano-sized Al 3 (Sc,Zr) dispersoids on sub-grain boundaries and dislocations, the solutionized 1445 Al-Li alloy sheet displays non-recrystallization characteristics, which corresponds to a high volume fraction of deformation textures of Copper {112}<111>, Brass {011}<211> and S {123}<634>. This non-recrystallization feature makes the 1445 Al-Li alloy suitable for thin sheet. In addition, due to the addition of minor Ni, Al 9 FeNi particles instead of Al 7 Cu 2 Fe particles are formed. [ABSTRACT FROM AUTHOR]

V addition with range from 0–0.09 wt % are added in extruded Al–Zn–Mg alloys to study the influence of V addition induced microstructures on the tensile strength and fatigue properties of Al–Zn–Mg alloys under T74 temper. The V addition significantly inhibits the recrystallization behavior of the alloy via forming Al 23 V 4 second phase particles, and the formation of coarse grain layer on the profile surface is gradually inhibited. The aging hardening curve, tensile strength, and fatigue strength of Al–Zn–Mg alloy with different V content are studied. It is discovered that an increase of V content obviously improves the tensile properties and the median fatigue strength of the investigated alloy, but has little effect on the aging hardening rate of the investigated alloys. In fact, the alloy with 0.09 wt % V content has the highest tensile properties, and its tensile strength and yield strength are 374.4 and 329.0 MPa, respectively. The alloy with 0.05 wt % V content achieves the maximum median fatigue strength, which is 183.6 MPa. After T74 aging treatment, the main strengthening mechanism is Orowan bypass strengthening mechanism. However, the excessive V addition has limited effect on the strength improvement of the studied alloys, and has adverse effects on tensile toughness and fatigue strength, mainly because the V atoms will agglomerate in the aluminum matrix and form micron-sized coarse V-rich particles, with an average particle size of about 10 μm. [ABSTRACT FROM AUTHOR]