摘要：Sodium-ion batteries are promising for large-scale energy storage due to sodium's low cost and infinite abundance. The most popular cathodes for sodium-ion batteries, i.e., the layered sodium-containing oxides, usually exhibit reversible host rearrangement between P-type and O-type stacking upon charge/discharge. Herein we demonstrate that such host rearrangement is unfavorable and can be suppressed by introducing transition-metal ions into sodium layers. The electrode with stabilized P3-type stacking delivers superior rate capability, high energy efficiency, and excellent cycling performance. Owing to the cation-mixing nature, it performs the lowest lattice strain among all reported cathodes for sodium-ion batteries. Our findings highlight the significance of a stable host for sodium-ion storage and moreover underline the fundamental distinction in material design strategy between lithium-and sodium-ion batteries.

摘要：Three acceptor-donor-acceptor （A-D-A） small molecules DCAODTBDT, DRDTBDT and DTBDTBDT using dithieno[2,3-d：2＇,3＇-d＇]benzo[1,2-b：4,5-b＇]dithiophene as the central building block, octyl cyanoacetate, 3-octylrhodanine and thiobarbituric acid as the end groups were designed and synthesized as donor materials in solution-processed photovoltaic cells （OPVs）. The impacts of these different electron withdrawing end groups on the photophysical properties, energy levels, charge carrier mobility, morphologies of blend films, and their photovoltaic properties have been systematically investigated. OPVs device based on DRDTBDT gave the best power conversion efficiency （PCE） of 8.34%, which was significantly higher than that based on DCAODTBDT （4.83%） or DTBDTBDT （3.39%）. These results indicate that rather dedicated and balanced consideration of absorption, energy levels, morphology, mobility, etc. for the design of small-molecule-based OPVs （SM-OPVs） and systematic investigations are highly needed to achieve high performance for SM-OPVs.

摘要：Fusion weld is a portable and economical joining and repairing method of ***,weld cracks often occur during the fusion weld of Ni-base superalloys,which hinder the applications of fusion weld on this kind of *** this work,the effects of microstructures of grain boundaries(GBs)of the prototype M951 superalloy on its weldability were *** precipitated phases,the elemental segregations on GBs,and the morphologies of GBs can be largely altered by regulating the cooling rates of pre-weld heat *** decreasing the cooling rate,chain-like M_(23)X_(6)phase precipitates along the GBs,accompanying segregations of B,and GBs becomes more serrated in *** fusion weld,the engineered GBs in the M951 superalloy with a low cooling rate favor the formation of the continuous liquid films on GBs,which together with the serrated GB morphology significantly prevents the formation of weld *** findings imply that the weld-crack resistance of the superalloys can be ameliorated by engineering GBs.

摘要：Exploring cobalt phosphide catalysts with abundant active sites and outstanding intrinsic activity for active and robust hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is highly ***,by the fine-tuning thermal-reduction treatment of cobalt phosphonates with spherical shape,the novel carbon-wrapped CoP-Co_(2)P polymorphs are rationally *** unique hierarchical porous architecture and heterointerface of CoP-Co_(2)P not only increase active sites but also ensure intrinsic *** resultant catalyst exhibits significantly boosted HER activity in a wide pH range,for instance,a current density of 10 mA cm^(-2) at the overpotential of 81 mV in 0.5 mol L^(-1) H_(2)SO_(4),109 mV in 1.0 mol L^(-1) KOH,and 227 mV in 1.0 mol L^(-1) phosphate buffer saline,and remarkable OER activity(1.53 V@10 mA cm^(-2) in 1.0 mol L^(-1) KOH),associated with the impressive stability for each ***,serving as the bifunctional electrocatalysts in a two-electrode electrolyzer for overall water splitting,a low cell voltage of 1.60 V can deliver a current density of 10 mA cm^(-2) in 1.0 mol L^(-1) *** structural evolution process of the CoP-Co_(2)P catalyst during electrolysis is thoroughly *** work presents a new approach for designing and fabricating efficient and affordable metal phosphides for various electrochemical technologies.

摘要：The 21 dog-bone specimens with different fiber contents and fiber distribution (random chopped fiber or directional continuous filament fiber bundles) were designed and tested under uniaxial tension using domestic PVA (polyvinyl alcohol) *** fiber content exerted positive influences on cracking stress,peak stress and deformation capacity of specimens with random chopped fiber,compared with the decrease shown in cracking stress of specimens containing directional fiber *** were multiple cracks in specimens containing directional fiber bundles,while only 1-2 typical cracks could be shown in chopped fiber specimens after being *** chopped fiber connected more closely with matrix compared with that only part of fiber bundles could contact with ***-fold line model and parabolic model could be used simultaneously to fit well with the uniaxial tension constitutive relations of engineered cementitious composite (ECC).Although the performance of PVA produced in China can not reach to the same level of those from Japan,there exists certain practical value in engineering according to its contribution to deformability of structure.

摘要：The solution-processed method for organic light-emitting diodes(OLEDs)offers the benefits of cost-effectiveness and enhanced material *** the multilayer architecture of solution-processed OLEDs(SOLEDs),the role of hole-transport materials(HTMs)is pivotal for cascade hole ***,commercial HTMs such as poly-(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine)(TFB)are hampered by incompatible energy levels and redissolution with overlayer solvent,prompting the exploration of cross-linkable HTMs(X-HTMs)for better *** this study,we have developed two novel small-molecule X-HTMs,N^(1),N^(1)′-((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(N^(4),N^(4)-diphenyl-N^(1)-(4-vinylphenyl)benzene-1,4-diamine)(FTPA-V)and N,N′-((perfluoropropane-2,2-diyl)bis-(4,1-phenylene))bis(9-phenyl-N-(4-vinylphenyl)-9H-carbazol-3-amine)(FPCz-V),which incorporate thermally cross-linkable vinyl groups and electron-rich trifluoromethyl *** X-HTMs enhance interfacial contact through superior film formation and solvent resistance,along with optimal energy *** application of X-HTMs significantly enhances the efficiencies and longevities of blue,green,and red ***,blue SOLED incorporating FPCz-V exhibits unprecedented lifetime(LT95)extending to over 150 h,setting a new record for blue *** electrochemistry stability,high bond dissociation energy,and triplet energy levels of X-HTMs can effectively minimize exciton annihilation and prolong the *** findings underscore the potential of X-HTM optimization to propel the development of stable solution-processed luminescent technologies.

摘要：To increase the service life of rechargeable batteries,transition metal oxide hosts with high structural stability for the intercalation of carrier ions are ***,we reconstruct the crystal structure of a commercial V_(2)O_(5)by pre-intercalating H^(+)and H_(2)O pillars using a facile hydrothermal reaction and obtain a bi-layer structured H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)as an excellent host for aqueous Zn-ion *** from the structural reconstruction,the irreversible“layer-to-amorphous”phase evolution during cycling is considerably less,resulting in ultra-high cycling stability of HVO with nearly no capacity fading even after 500 cycles at a current density of 0.5Ag^(-1).Moreover,a synthetic proton and Zn^(2+)intercalation mechanism in the HVO host is *** work provides both a facile synthesis method for the preparation of V-based compounds and a new viewpoint for achieving high-performance host materials.

摘要：The rational design and construction of hierarchically porous nanostructure for oxygen reduction reaction (ORR) electrocatalysts is crucial to facilitate the exposure of accessible active sites and promote the mass/electron transfer under the gas-solid-liquid triple-phase condition. Herein, an ingenious method through the pyrolysis of creative polyvinylimidazole coordination with Zn/Fe salt precursors is developed to fabricate hierarchically porous Fe-N-doped carbon framework as efficient ORR electrocatalyst. The volatilization of Zn species combined with the nanoscale Kirkendall effect of Fe dopants during the pyrolysis build the hierarchical micro-, meso-, and macroporous nanostructure with a high specific surface area (1,586 m^(2)·g^(−1)), which provide sufficient exposed active sites and multiscale mass/charge transport channels. The optimized electrocatalyst exhibits superior ORR activity and robust stability in both alkaline and acidic electrolytes. The Zn-air battery fabricated by such attractive electrocatalyst as air cathode displays a higher peak power density than that of Pt/C-based Zn-air battery, suggesting the great potential of this electrocatalyst for Zn-air batteries.

摘要：We developed and demonstrated a ZnO/ZnS/Au composite photoanode with significantly enhanced photoelectrochemical water-splitting performance, con- taining a ZnS interlayer and Au nanoparticles. The solar-to-hydrogen conversion efficiency of this ZnO/ZnS/Au heterostructure reached 0.21%, 3.5 times that of pristine ZnO. The comparison of the incident photon-to-current efficiency （IPCE） and the photoresponse in the white and visible light regions further verified that the enhancement resulted from contributions of both UV and visible light. The modification of the Au NPs was shown to improve the photoelectrochemical （PEC） performance to both UV and visible light, as modification encouraged effective surface passivation and surface-plasmon- resonance effects. The ZnS interlayer favored the movement of photogenerated electrons under UV light and hot electrons under visible light, causing their injection into ZnO; this simultaneously suppressed the electron-hole recombination at the photoanode-electrolyte interface. The optimized design of the interlayer within plasmonic metal/semiconductor composite systems, as reported here, provided a facile and compatible photoelectrode configuration, enhancing the utilization efficiency of incident light for photoelectrochemical applications.

摘要：A well-designed redox-active organic linker,pyrazine-2,3,5,6-tetracarboxylate(H_4pztc)with brimming active sites for lithium ions storage was utilized to construct coordination polymers(CPs)via a facile hydrothermal *** two isostructural two-dimensional(2D)CPs,namely[M_2(pztc)(H_2O)_6]_n(M=Co for 1 and Ni for 2),delivered excellent reversible capacities and stable cycling performance as anodes in lithium ion *** demonstrated in electrochemical studies,1 and 2 can achieve highly reversible capacities of 815 and 536 mA h g^(-1)at 200 mA g^(-1)for 150 cycles,respectively,best performed for the reported2D-CP-based anode *** electrochemical mechanism studies showed that the remarkable performances can be ascribed to the synergistic Li-storage redox reactions of metal centers and organic *** work highlights the opportunities of using a well-designed organic ligand to construct low-dimensional CPs as new type of electrode materials for advanced lithium ion batteries.