A metallic nanoparticle-decorated ceramic anode was prepared by in situ reduction of the perovskite Sr2FeMo0.65Ni0.35O6-δ (SFMNi) in H2 at 850 °C. The reduction converts the pure perovksite phase into mixed phases containing the Ruddlesden-Popper structure Sr3FeMoO7-δ, perovskite Sr(FeMo)O3-δ, and the FeNi3 bimetallic alloy nanoparticle catalyst. The electrochemical performance of the SFMNi ceramic anode is greatly enhanced by the in situ exsolved Fe-Ni alloy nanoparticle catalysts that are homogeneously distributed on the ceramic backbone surface. The maximum power densities of the La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte supported a single cell with SFMNi as the anode reached 590, 793, and 960 mW cm(-2) in wet H2 at 750, 800, and 850 °C, respectively. The Sr2FeMo0.65Ni0.35O6-δ anode also shows excellent structural stability and good coking resistance in wet CH4. The prepared SFMNi material is a promising high-performance anode for solid oxide fuel cells.

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couple high-capacity sulfur positive electrodes with earth-abundant sodium negative electrodes are unsurprisingly considered as a promising candidate. [8][9][10][11] In the process of cycle, the elemental sulfur of the cathode is dissolvated, reduced to form various soluble polysulfides, that is, S x 2− ions and radicals (1 ≤ x ≤ 8), and eventually the insoluble Na 2 S 2 and Na 2 S. [8,10,12] However, the practical applications are seriously hindered by several obstacles, in which the fundamental challenges are originated from the insulating properties of elemental sulfur and sodium sulfides, the volume changes at the cathode on cycling and the dissolution of sodium poly sulfides in the electrolyte. [9,[13][14][15] To date, extensive efforts have been made toward the enhancement of RT-Na/S batteries, including Na 2 S cathodes, [16,17] carbonaceous buffer matrixes, [12,18,19] a class of sodium polysulfides, [20,21] and the functional carbon-coated Nafion separator. [22] These approaches, while are validated to improve the cyclability of the RT Na-S batteries, tend to result in complicated synthetic processes and decreased theoretical capacity. In addition, it was suggested that the polar-polar interaction is a strong chemical interaction between polar sodium polysulfides and polar host materials. [23,24] Although there is no universal conclusion on the exact configuration of the interactions due to the complexity of carbon matrix, their similar effect in suppressing the polysulfide shuttle has also been reported in Li-S battery systems. [25][26][27] Instead of relying on polar-polar interactions, the suitably tailored hosts can bind sodium polysulfides through metal-sulfur bonding. Examples of such materials are sub-stoichiometric metal chalcogenides, MXene phases and metal-organic frameworks (MOFs). [28][29][30][31] In practice, these oxide and sulfide materials are able to bridge sodium polysulfides through both polar-polar Na-S(O) interaction and Lewis acid-base bonding, depending on the exposed facets to some extent. [25,32] However, to simply increase metal and/or binder content only neutralizes the advantageous energy density of the overall cell. Moreover, most of the sulfur-carbon electrode materials are directly prepared using elemental S and various carbon matrixes as started materials through vapor-infiltration or meltinfusion method. [8,10] As a result, the aggregated particles are Room temperature sodium-sulfur batteries have emerged as promising candidate for application in energy storage. However, the electrodes are usually obtained through infusing elemental sulfur into various carbon sources, and the precipitation of insoluble and irreversible sulfide species on the surface of carbon and sodium readily leads to continuous capacity degradation. Here, a novel strategy is demonstrated to prepare a covalent sulfur-carbon complex (SC-BDSA) with high covalent-sulfur concentration (40.1%) that relies on SO 3 H (Benzenedisulfonic acid, BDSA) and SO 4 2− as the sulfur source rather than elemental sulfur. M...

A broadband and lightweight microwave absorber has attracted soaring research interest because of the increasing demand for electronic reliability and defense security. Lightweight ferrites/graphene porous composites with abundant interfaces are potential high-performance absorbers owing to their balanced attenuation ability and impedance matching. Herein, we synthesized hierarchical CoFeO/reduced graphene oxide (CFO/rGO) nanocomposites with a porous structure via an in situ solvothermal method. The electromagnetic parameters of CFO/rGO nanocomposites can be well-adjusted by modulating the weight fraction of rGO. The hierarchical porous structure and proper electromagnetic parameters result in the enhancement of impedance matching and attenuation ability. Benefiting from the controllable composition, hierarchical porous structure, and strong synergetic effect between CFO and rGO sheets, as expected, CFO/rGO nanocomposites exhibit superior microwave absorption performance with an ultrabroad bandwidth reaching 5.8 GHz (8.3-14.1 GHz) with a thin thickness of 2.8 mm. Meanwhile, a strong reflection loss of -57.7 dB at the same thickness is achieved. Considering the outstanding microwave absorption performance, the hierarchical CFO/rGO porous nanocomposites can be employed as a high-performance microwave absorber.

Liquid-crystalline blue phases (BPs) have sparked an enormous interest due to their exotic optical properties, exhibiting no birefringence but selective refl ection of circularly polarized light, and potential for advanced applications in a wide variety of fi elds including self-assembling tunable photonic crystals and fast-response display. [ 1 ] BPs are made up of double-twist cylinders arranged in a highly fl uid self-assembled cubic lattice with periods of ∼ 100 nm, which is stabilized by a network of topological -1/2 disclination lines. The competition between the chiral forces and the packing topology leads to at least three different lattice structures, labeled as blue phase III (BPIII), blue phase II (BPII), and blue phase I (BPI) upon decreasing the temperature from the isotropic (I) to the chiral nematic phase. [ 2 ] The packing structures are macroscopically amorphous, simple cubic, and body-centered cubic, respectively. [ 3 ] As is known, the main obstacles to the potential applications of the BPs are the narrow temperature range as well as the instability of cubic structure against an electric fi eld. [ 4 ] Recent developments that introduce BPs with an extended temperature range [ 5 ] make them more attractive for applications. However, the stability of cubic structures against an electric fi eld, such as heavy hysteresis or irreversible switching, is still a big challenge on the road toward practical applications.Theoretical investigations of the BP switching dynamics in presence of an electric fi eld have shown that cubic structure (especially, BPI) is unstable and diffi cult to be reversibly switched in the strong fi eld region. [ 6 ] It has been experimentally demonstrated that serious hysteresis was observed in the pure BPs, which may be due to the fi eld induced phase transition from BP to a chiral nematic phase. [ 7 ] Interestingly, polymer-stabilized BPs (PSBP) could be reversibly switched with microsecond response time, [ 5 ] but the driving voltage of these system is relatively high due to the doping of ∼ 10.0 wt% monomers, and the long-term stability of polymer network is a remaining technical challenge. [ 1 , 8 ] Moreover, BPIII could also undergo a reversible switching with an AC fi eld of less than 10.0 V μ m − 1 but the response speed is relatively slow (about several millisecond) due to the fact that BPIII with wide temperature range is usually observed in the systems with high chirality or viscosity. [ 9 ] Therefore, there is an urgent need to explore a novel strategy to solve the instability of cubic BPs against an electric fi eld and develop the BP composites without hysteresis, with fast response speed, and with low driving voltage.Liquid-crystal nanoscience has attracted special attention in recent years due to the potential applications in developing new composite materials with exciting optical as well as electro-optical properties. [ 10 ] Doping nematic liquid crystals (LC) with nanoparticles (NPs) has lead to many promising LC electro-optical characteristics including low ...