According to a space-charge theory analysis, the space-charge potential of YSZ is negative, which corresponds to a V-0(..) depletion in the space-charge layer. An extremely low grain-boundary conductivity of the high-...
According to a space-charge theory analysis, the space-charge potential of YSZ is negative, which corresponds to a V-0(..) depletion in the space-charge layer. An extremely low grain-boundary conductivity of the high-purity YSZ is thus explained. Under the condition that the bulk property is ensured by the optimal dopant additions, an idea of increasing the grain-boundary conductivity by the segregations of solutes with positive effective charge is put forward. The most likely driving force for the segregations is the elastic strain energy. And the feasibility of this idea has been proved by some experimental and theoretical results.
Carbon nanofibers(CNFs)with excellent electric conductivity and high surface area have attracted immense research interests in ***,the macroscopic production of CNFs still remains a great ***,ultrafine N–doped CNFs(N...
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Carbon nanofibers(CNFs)with excellent electric conductivity and high surface area have attracted immense research interests in ***,the macroscopic production of CNFs still remains a great ***,ultrafine N–doped CNFs(N–CNFs)with a diameter of$20 nm are synthesized through a simple and scalable sol-gel method based on the self-assembly of phenolic resin and cetyltrimethylammonium *** employed in aqueous supercapacitors,the obtained activated N–CNFs manifest a high gravimetric/areal capacitance(380 Fg-1/1.7 Fcm-2)as well as outstanding rate capability and cycling ***,the activated N–CNFs also demonstrate excellent capacitive performance(330 Fg-1)in flexible quasi-solid-state *** remarkable electrochemical performance as well as the easy and scalable synthesis makes the N–CNFs a highly promising electrode material for supercapacitors.
Zn-air batteries(ZABs)as a class of promising energy storage setups are generally powered by efficient and robust catalysts at the oxygen-involving *** the existing non-noble catalysts have outperformed noble Pt bench...
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Zn-air batteries(ZABs)as a class of promising energy storage setups are generally powered by efficient and robust catalysts at the oxygen-involving *** the existing non-noble catalysts have outperformed noble Pt benchmark in the alkaline liquid-state ZABs,to the best of our knowledge few have excelled Pt in quasi-solid-state(QSS)***,we found that an integrated Mn-Co cathode derived from the bimetallic Mn/Co metal organic frameworks generates a 1.4-fold greater power density in the QSS ZABs than a Pt cathode while its power density in liquid-state ZABs is only 0.8-fold of the ***,such Mn-Co catalyst delivers high-rate oxygen reduction reaction(ORR)capability with half-wave potential of 0.84 *** in-depth characterizations and analyses have demonstrated that the Co and Mn species show the specific affinity towards H_(2)O and O_(2),respectively,synergizing the ORR process in the water-deficient environment of QSS *** work has enlightened the rational design of non-noble metal catalysts to improve the power density of QSS ZABs.
Selenium sulfide/double-layered hollow carbon sphere (SeS2/DLHC) composites have been designed as high-performance cathode materials for novel Li-SeS2 batteries. In the constructed composite, SeS2 is predominantly e...
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Selenium sulfide/double-layered hollow carbon sphere (SeS2/DLHC) composites have been designed as high-performance cathode materials for novel Li-SeS2 batteries. In the constructed composite, SeS2 is predominantly encapsulated in the interlayer space of DLHCs with a high loading of 75% (weight percentage) and serves as the active component for lithium storage. The presence of Se in the composite and the carbon framework not only alleviate the shuttling of polysulfide, but also improve the conductivity of electrodes. Migration of active materials from the interlayer void to the hollow cavity of DLHCs after cycling, which further mitigates the loss of active materials and the shuttle effect, is observed. As a result, the SeS2/DLHC composite delivers a high specific capacity (930 mA.h.g-1 at 0.2 C) and outstanding rate capability (400 mA.h.g-1 at 6 C), which is much better than those of SeS2/single-layered hollow carbon sphere, Se/DLHC, and S/DLHC composites. Notably, the SeS2/DLHC composite shows an ultralong cycle life with 89% capacity retention over 900 cycles at 1 C, or only 0.012% capacity decay per cycle. Our study reveals that both SeS2 and the double-layered structures are responsible for the excellent electrochemical performance.
It is a pleasure to dedicate this special issue of Chinese Journal of Catalysis(CJC)to *** ***,Choh-Ming Li Professor of Chemistry at The Chinese University of Hong *** is to celebrate the 20th anniversary of his re...
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It is a pleasure to dedicate this special issue of Chinese Journal of Catalysis(CJC)to *** ***,Choh-Ming Li Professor of Chemistry at The Chinese University of Hong *** is to celebrate the 20th anniversary of his return to Hong Kong and leading photocatalytic research there.
Reduced graphene oxide(rGO)enhanced B_(4)C ceramics was prepared by SPS sintering,the enhancement effect of rGO on the microstructure and mechanical properties of composites was studied through experiments and numeric...
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Reduced graphene oxide(rGO)enhanced B_(4)C ceramics was prepared by SPS sintering,the enhancement effect of rGO on the microstructure and mechanical properties of composites was studied through experiments and numerical *** results show that the composite with 2wt%rGO has the best comprehensive mechanical *** with pure boron carbide,vickers hardness and bending strength are increased by 4.8%and 21.96%,*** fracture toughness is improved by 25.71%.The microstructure observation shows that the improvement of mechanical properties is mainly attributed to the pullout and bridge mechanism of rGO and the crack *** on the cohesive force finite element method,the dynamic crack growth process of composites was *** energy dissipation of B_(4)C/rGO multiphase ceramics during crack propagation was calculated and compared with that of pure boron carbide *** results show that the fracture energy dissipation can be effectively increased by adding graphene.
The high energy density and long cycling life of zinc-based batteries are restricted by the single electro-chemical reaction *** improve the electrochemical performance of batteries,electrode materials,electrolytes an...
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The high energy density and long cycling life of zinc-based batteries are restricted by the single electro-chemical reaction *** improve the electrochemical performance of batteries,electrode materials,electrolytes and membranes are regularly modified,while the construction of battery systems is often ***,a multifunctional electrode was prepared via 3D printing,which successfully coupled the metal oxide/hydroxide-zinc battery(MZB)reaction and rechargeable zinc-air battery(RZAB)*** ultrathick hierarchical 3D electrode provided a tunable capacity for the MZB system,which enabled the possibility for feasible output regulation of this hybrid *** active material NiCoLDH was discov-ered to undergo structure reconstruction during cycling,which revealed the capacity fading *** delicate system design and discovery ensured a high-performance battery configuration and revealed the corresponding mechanism,opening a new avenue for developing high-performance zinc batteries.
Emerging stimuli-responsive composite probes active in the second nearinfrared window(NIR-II,1000–1700 nm)hold vast potential for improving in vivo imaging performance with minimized noise *** interactions among exte...
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Emerging stimuli-responsive composite probes active in the second nearinfrared window(NIR-II,1000–1700 nm)hold vast potential for improving in vivo imaging performance with minimized noise *** interactions among external irradiation,shell species,and the emissive core are key factors in the design of smart *** external irradiation provides energy for shell species and the emissive core to generate intense NIR-II fluorescence signals,while the energy transfer process hinders NIR-II emission in the inner structure of smart composite ***,if pathophysiological stimuli interrupt the above processes,then NIR-II fluorescence signals are *** review covers NIR-II imaging based on diverse smart composite NIR-II fluorescent probes responding to various biological stimuli,including ONOO−,overexpressed reactive sulfur species,abnormally expressed enzymes,and abnormal levels of physiological ***,to appreciate these advances,the challenges and perspectives of stimuliresponsive composite NIR-II probes are highlighted.
An improved multi-step sintering process was used to in-situ prepare TiB2-TiB-Ti FGMs. According to the sintering temperatures, the functionally graded materials (FGMs) were divided into three sections. After sinter...
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An improved multi-step sintering process was used to in-situ prepare TiB2-TiB-Ti FGMs. According to the sintering temperatures, the functionally graded materials (FGMs) were divided into three sections. After sintering at a proper temperature, the three sections were sintered together in turn. The experimental results showed that there were no obvious pores and cracks in the whole TiB2-TiB-Ti FGMs, and no delamination was found in the impacting test with good performance features, which indicated that there were no interface effects in FGMs during penetration, so that the TiB2-TiB-Ti FGMs were an ideal FGM.
The spherical agglomerated particles were fabricated by spray drying with the powders of NiO, Cr2O3 and TiO2. Plasma spray power, which has good property of flowability, was acquired by heat treatment from the particl...
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The spherical agglomerated particles were fabricated by spray drying with the powders of NiO, Cr2O3 and TiO2. Plasma spray power, which has good property of flowability, was acquired by heat treatment from the particles at 1200℃ in the reducing atmosphere. Dark and uniform coating of More than 50 μm thick was deposited on the copper sheet substrate by plasma spraying. It is found that the infrared normal total emissivity of the coating is up to 0.91 at 600℃ by infrared radiation testing. The X-ray diffraction analysis shows that the formation of (Cr0.88Ti0.12)2O3 and spinel structural NiCr2O4 in the coating is the main reason for high efficient infrared radiation, and the phase structure and performance of coating is favorable under the thermal cycle between room temperature and 600℃.
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