Reversible solid oxide cells (RSOCs) as clean and efficient electrochemical conversion and storage devices have received much attention. PrFeO3-δ has been investigated to obtain excellent performance ...when it is used as air electrode for RSOCs. In this work, we investigate a novel PrFeO3-δ based orthorhombic perovskite oxide Pr0.8Ca0.2Fe0.8Co0.2O3-δ and use it as the air electrode of RSOCs. The electrochemical performance of this cell with Pr0.8Ca0.2Fe0.8Co0.2O3-δ electrode is presented in detail. The highest power density at 850 °C can reach 1.762 W cm−2 in fuel cell mode using hydrogen as fuel. And the electrolysis current density of 2.23 A cm−2 at 850 °C can be achieved under the condition of 50 vol % absolute humidity at 1.3 V in electrolysis cell mode. Moreover, during a long-term operation of up to 200 h, this cell can remain stable and shows good reversibility in two modes. These results demonstrate that the perovskite Pr0.8Ca0.2Fe0.8Co0.2O3-δ is promising air electrode for RSOCs.
•Sr-free Pr0.8Ca0.2Fe0.8Co0.2O3-δ (PCFC) is constructed by Ca and Co co-doping.•The maximum power density reaches 1.29 W/cm2 at 800 °C in SOFC mode.•The current density is 1.4 A/cm2 at 1.3 V with 50% AH at 800 °C in SOEC mode.•The cell exhibits long-term stability of 200 h under reversible operation mode.
Reversing Petri nets (RPNs) have recently been proposed as a net-based approach to model causal and out-of-causal order reversibility. They are based on the notion of individual tokens that can be ...connected together via bonds. In this paper we extend RPNs by allowing multiple tokens of the same type to exist within a net and we implement a notion of local reversibility for the model based on the collective token interpretation of Petri nets. The resulting framework allows us to model a form of out-of-causal-order reversibility, a type of reversibility that arises most notably in biological systems. Furthermore, it is lightweight in the sense that it requires no global control and no history needs to be preserved. Furthermore, we provide a mechanism for controlling reversibility by associating transitions with conditions, which guard their execution. We demonstrate the usefulness of the framework by modelling the functioning of the sodium-potassium pump, a system where transition execution is governed by activation conditions and featuring reversible behaviour.
•Introduction of token multiplicity in RPNs.•Local reversibility semantics yielding a form of out-of-causal order reversibility.•Introduction of a mechanism for controlling reversibility based on the association of conditions to transitions.•A model of the sodium-potassium pump.
A new rhodamine-6G hydrazone RHMA has been synthesized using rhodamine-6G hydrazide and 5-Allyl-3-methoxysalicylaldehyde. RHMA has been fully characterized with different spectroscopic methods and ...single crystal XRD. RHMA can selectively recognize Cu2+ and Hg2+ in aqueous media amongst other common competitive metal ions. A significant change in absorbance was observed with Cu2+ and Hg2+ ions with emergence of a new peak at λmax 524 nm and 531 nm respectively. Hg2+ ions lead to “turn-on” fluorescence enhancement at λmax 555 nm. This event of absorbance and fluorescence marks the opening of spirolactum ring causing visual color change from colorless to magenta and light pink.RHMA-Cu2+ and RHMA- Hg2+complexes are found to be reversible in presence of EDTA2−ions. RHMA has real application in form of test strip. Additionally, the probe exhibits turn-on readout-based sequential logic gate-based monitoring of Cu2+ and Hg2+ at ppm levels, which may be able to address real-world challenges through simple synthesis, quick recovery, response in water, “by-eye” detection, reversible response, great selectivity, and a variety of output for accurate investigation.
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•A new rhodamine hydrazone (RHMA) is synthesized and characterized using physicochemical and X-ray diffraction techniques.•RHMA shows fast and selective detection of Cu2+and Hg2+ ions.•The recognition behavior is found to be reversible with EDTA ions.•RHMA has practical application in form of paper strip test.•Sequential logic gates and keypad locks were constructed by inputs Cu2+, Hg2+ and EDTA.
An osmotic dilution process of hybrid forward osmosis (FO) and reverse osmosis (RO) was applied at pilot-scale to integrate wastewater treatment with seawater desalination in a municipal wastewater ...treatment plant. The aim of this study is to expand the understanding of multiple FO fouling indexes (i.e., MFI-UF and ORI) to not only obtain insight on fouling characteristics of the FO process but also optimize the operation of the osmotic dilution process. The correlation between the fouling indexes and performance of the FO membrane (i.e., transmembrane inlet pressure (TMIP), differential pressure (DP)) was first validated based on the operation data from the seven-month pilot run. MFI-UF was then selected for measuring the fouling potential according to the pretreatment process (or source water), whereas ORI was obtained for optimizing the cleaning protocol of the FO process to support the stable operation of the FO plant. The sensitivity analysis of the seasonal effect verified the correlation between MFI-UF and FO performance. The results of this study are expected to provide practical insight and technical guidelines to FO based plant engineers/operators.
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•Applicability of multiple FO fouling indexes was validated at pilot scale.•Long-term performance was assessed by adopting different pretreatment strategies.•A close relationship between MFI-UF and FO ΔDP was observed.•ORI was able to predict the FO TMIP precisely.•MFI-UF and ORI can be applied as plant–assistance criteria for FO process.
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•The dehydrogenation induction period is completely eliminated.•9.4 wt% H2 can be reversibly hydrogenated at 200 °C.•The catalytic mechanism of K2TiF6 is investigated in detail.•TiB2 ...nano-particles can stably exist during 10 cycles.•F substitution can destabilize LiBH4 and LiF to de/rehydrogenate.
Developing convenient and applicable strategies to synthesize hydrogen storage composites with high capacity and favorable reversibility is vital in the field of novel energy materials. Herein, a system of 2LiBH4-MgH2 with K2TiF6 is synthesized, in which K2TiF6 can react with LiBH4 to form TiB2, LiF, KBH4. Such composite possesses low onset dehydrogenation temperatures, completely eliminated dehydrogenation induction period and fast kinetics with low activation energies of 100.3 kJ/mol. Considering that the reaction between K2TiF6 and LiBH4 can reduce the practical capacity, excess LiBH4 was added into the composite to offset the reduced dehydrogenation capacity. The cycling performances of the composite with excess LiBH4 are greatly improved. The composite with excess LiBH4 can completely absorb 9.4 wt% H2 at 200 °C, close to the practical operating temperatures of the fuel cell system on vehicle. This is exceedingly outstanding among the reversible properties of 2LiBH4-MgH2. Characterization analyses and theoretical calculations indicate the in situ formed TiB2, LiF, and KBH4 can perform stable synergetic catalytic effect on the hydrogen storage performances of 2LiBH4-MgH2 from thermodynamic and kinetic aspects. The TiB2 nanoparticles can improve dehydrogenation kinetics by acting as heterogeneous nucleation agents and modifying kinetic model. KBH4 can form eutectic composites with LiBH4 to start dehydrogenation at low temperatures. LiF can transform into LiH1-xFx during dehydrogenation and LiBH4-xFx during rehydrogenation. Such fluoride substitution can thermodynamically destabilize LiH and LiBH4 to improve hydrogen de/absorption properties. The novel synergetic mechanism provides a new and comprehensive inspiration for improving the reversible hydrogen storage properties of 2LiBH4-MgH2.
The furan-maleimide Diels-Alder chemistry has emerged as an important tool to design thermo-reversible click networks. This not only preserves the strong and robust properties of thermo-sets and ...rubbers, but also makes it possible to cleave crosslinks at non-degradative temperatures, or in other words to recycle them. In this work a new reaction is reported in furan-maleimide click networks, which is the Double-Diels-Alder reaction (DDA), also known as domino Diels-Alder. This forms extra linkages between Diels-Alder adducts and non-reacted furan groups and evidently leads to stronger materials, but also prevents efficient thermal (re)cycling. This work shows with nuclear magnetic resonance (NMR) characterization, differential scanning calorimetry (DSC) and rheology that the DDA reaction can occur both in intramolecular and intermolecular fashion, but also that it exhibits reversibility just like the regular Diels-Alder reaction. This reaction can be easily overlooked creating what at first sight might be inexplicable reactivity when analyzing the properties of furan-maleimide click networks.
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•More understanding of irreversible side reactions in multifunctional furan-maleimide systems is required.•An intramolecular double Diels-Alder in these systems can already occur at 40 °C.•Intermolecular double Diels-Alder can occur slowly when held isothermally at retro-Diels-Alder temperatures.•The intramolecular Diels-Alder between furfuryl-sulfide and a single adduct is reversible at 160–180 °C.•Formation of domino adducts can be prevented by avoiding an excess of mobile furan moieties.
•Local phase coexistence enhances the ESPs of the (1−x)BNT-xSLZT ceramics.•The Wrec of 5.09 J/cm3 and η of 88% are achieved in 0.67BNT-0.33SLZT ceramic.•The ceramic displays good thermal stability ...from 0 °C to 200 °C.•The coexistence of P4bm and Pm-3 m phases increases the Eb of the ceramic.
Dielectric capacitors with excellent energy storage performance are highly desirable for electronic industry. Although many excellent studies have been carried out on energy-storage dielectric materials, the explanation of their macroscopic electrical properties from the microscopic point of view remains scarce. In this work, (1-x)Bi0.5Na0.5TiO3-xSr0.7La0.2Zr0.15Ti0.85O3 ((1-x)BNT-xSLZT) relaxor ceramics are designed and fabricated. The recoverable energy density of 5.09 J/cm3 and efficiency of 88% are achieved in 0.67BNT-0.33SLZT ceramic. The ceramic also displays an excellent thermal stability in a wide temperature range (0–200 °C). The good performance of the ceramics is attributed to their heterogeneous structure which contains two different local phases after composition modification. Micro-structure is then validated by the Rietveld refinement and transmission electron microscopy analysis. Moreover, the decrease in domain size and enhancement in domain reversibility are also observed in the sample. The delayed polarization saturation and increased electric field strength significantly enhance the energy storage properties of the ceramics. This work indicates that constructing local phase coexistence is an effective method for obtaining high-performance energy storage ceramics, and may provide a guideline for designing and preparation of dielectric energy storage ceramics with superior properties.
To improve the packing efficiency in tank scale, hydrides have been compacted into pellet form; however, poor hydrogen permeability through the pellets results in sluggish kinetics. In this work, the ...hydrogen sorption properties of compacted 2LiBH4MgH2 doped with 30 wt % activated carbon nanofibers (ACNF) are investigated. After doping with ACNF, onset dehydrogenation temperature of compacted 2LiBH4MgH2 decreases from 350 to 300 °C and hydrogen released content enhances from 55 to 87% of the theoretical capacity. The sample containing ACNF releases hydrogen following a two-step mechanism with reversible hydrogen storage capacities up to 4.5 wt % H2 and 41.8 gH2/L, whereas the sample without ACNF shows a single-step decomposition mainly from MgH2 with only 1.8 wt % H2 and 15.4 gH2/L. Significant kinetic improvement observed in the doped system is due to the enhancement of both hydrogen permeability and heat transfer through the pellet.
•Compacted 2LiBH4MgH2 doped with ACNF to improve H2 diffusion and heat transfer.•Reduction of onset desorption temperature by 50 °C after doping with ACNF.•Enhanced reversible capacities from 1.8 to 4.5 wt % H2 and 15.4 to 41.8 gH2/L.•Increase of H2 permeability and heat transfer by 10 and ∼1.5 times, respectively.•Reduced EA by 67 kJ/mol with maintained mechanical stability upon cycling.
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Supramolecular polymer bottlebrushes (SPBs) consist in the 1D self-assembly of building blocks composed of a self-assembling core with pendant polymer arms. Kinetic hurdles often ...hinder their stimuli-responsiveness in solution. Changing the nature of the solvent should alleviate these hurdles by modulating the self-association strength, leading to stimuli-responsive SPBs.
The SPBs were formed, in various solvents, by hydrogen bond-driven self-assembly of an azobenzene-bisurea decorated with poly(ethylene oxide) polymer arms. The photo-isomerization of the azobenzene unit was studied by UV/visible spectroscopy and proton NMR spectroscopy, whereas the consequences on supramolecular self-assembly were studied by small angle neutron and X-ray scattering.
In water, the assembly was previously shown to be driven by both hydrogen-bonds and strong hydrophobic effects, the latter rendering the system kinetically frozen and the disassembly irreversible. Here we show that in organic solvents such as toluene or chloroform, reversible light-responsive dissociation is achieved. Solvophobic effects in these solvents are expected to be much weaker than in water, which probably allows reversibility of the light-response in the former solvents. The key role of the solvent on the reversibility of the process opens up new perspectives for the design of stimuli-responsive SPBs and their applications in various fields.
•A concept of locally concentrated electrolyte was proposed.•A nanoporous Zn electrode with accurately controlled pore size was fabricated.•Interface-localized concentrated electrolyte was realized ...via space charge effect.•The nanoporous Zn||NaVO3 full cell displayed a high capacity and long lifespan.
Rechargeable aqueous Zn metal batteries are promising for large-scale renewable energy storage. However, the aqueous Zn metal battery chemistry encounters severe irreversibility issues, as manifested by the non-uniform metallic Zn plating and undesired side-reactions of corrosion. Herein, we report a highly-reversible aqueous Zn metal anode with accurately controlled nanopore structure, by which the space charge distribution could be regulated and interface-localized concentrated electrolyte was enabled. Consequently, the nanoporous Zn (npZn) electrode exhibited high electrochemical reversibility for 750 h under the measurement with a combination of electrochemically Zn stripping/plating cycling (1 mA cm−2 and 1 mAh cm−2 for 25 cycles) and resting (50 h), and looping. Moreover, a npZn||NaVO3 cell exhibited a high capacity of 200 mAh g−1 and a long lifespan with considerable capacity retention (76% for 1500 cycles), and high reversibility (Coulombic efficiency of 99.8%), which was more stable than the counterpart with pristine Zn anode (short-circuit after 600 cycles).
