A Complexing Agent to Enable a Wide-Temperature Range Bromine-Based Flow Battery for Stationary Energy Storage

Bromine-based flow batteries (Br-FBs) are considered one of the most promising energy storage systems due to their features of high energy density and low cost. However, they generally suffer from uncontrolled diffusion of corrosive bromine particularly at high temperatures. That is because the interaction between polybromide anions and the commonly used complexing agent (N–methyl–N–ethyl–pyrrolidinium bromide [MEP]) decreases with increasing temperatures, which causes serious self-discharge and capacity fade. Herein, a novel bromine complexing agent, 1–ethyl–2–methyl–pyridinium bromide (BCA), is introduced in Br-FBs to solve the above problems. It is proven that BCA can combine with polybromide anions very well even at a high temperature of 60 °C. Moreover, the BCA contributes to decreasing the electrochemical polarization of Br⁻/Br₂ couple, which in turn improves their power density. As a result, a zinc–bromine flow battery with BCA as the complexing agent can achieve a high energy efficiency of 84% at 40 mA cm⁻², even at high temperature of 60 °C and it can stably run for more than 400 cycles without obvious performance decay. This paper provides an effective complexing agent to enable a wide temperature range Br-FB.     

Efficient hydrogen production for industry and electricity storage via high-temperature electrolysis

The paper describes the development status of Sunfire's reversible solid oxide cell (RSOC) technology. Here, Sunfire is a pioneer in the field of high-temperature electrolysers (HTE) for renewable hydrogen production which can be operated as a fuel cell for power generation in a reverse mode. The maturity of the technology is improved stepwise so that first applications in the field of hydrogen production for industry and electricity storage can be tackled. Three application examples where larger scale prototype has been installed will be discussed: 1) A power-to-power electricity storage based on hydrogen, 2) a RSOC unit that is installed in an iron and steel works, and 3) a pressurized SOEC prototype which will be integrated with a methanation unit. Results show the potentials of the technology in connection with fluctuating renewable energy sources.     

Single-Crystalline TiO2(B) Nanobelts with Unusual Large Exposed {100} Facets and Enhanced Li-Storage Capacity

The {100} facet of single-crystalline TiO₂(B) is an ideal platform for inserting Li ions, but it is hard to be obtained due to its high surface energy. Here, the single-crystalline TiO₂(B) nanobelts from H₂Ti₃O₇ with nearly 70% {100} facets exposed are synthesized, which significantly enhances Li-storage capacity. The first-principle calculations demonstrate an ab in-plane 2D diffusion through the exposed {100} facets. As a consequence, the nanobelts can significantly accommodate Li ions in LiTiO₂ formula with specific capacity up to 335 mAh g⁻¹, which is in good agreement with the electrochemical characterizations. Coating with conductive and protective poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), the cut-off discharge voltage is as low as 0.5 V, leading to a capacity of 160.7 mAh g⁻¹ after 1500 cycles with a retention rate of 66% at 1C. This work provides a practical strategy to increase the Li-ion capacity and cycle stability by tailoring the crystal orientation and nanostructures.     

Recovery of Sb(V) using a functional-ligand-containing porous hollow-fiber membrane prepared by radiation-induced graft polymerization

A ligand-containing porous membrane was prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer of glycidyl methacrylate onto a polyethylene porous hollow-fiber membrane and by subsequent conversion of the epoxy group to an N-methylglucamino (NMG) group at a density of 0.78 mmol/g of the membrane. Sb(V) solution was permeated through the NMG-ligand-containing porous hollow-fiber membrane. Optimum pH for Sb(V) recovery was 3.0. Breakthrough curves of Sb (V) overlapped irrespective of residence times of Sb (V) in the membrane, due to negligible diffusional mass-transfer resistance. Maximum amount of Sb (V) adsorbed was 130 mg/g-membrane, which was equivalent to 1.3 binding molar ratio. Repeated usage of the membrane for adsorption and elution was possible.     

Weakly non-linear stability of stratified natural convection in a vertical cavity with lateral temperature gradient

Stability of free convection is examined in a vertical cavity with a fixed lateral temperature difference on the walls, which is also heated from the bottom by a constant heat flux causing vertical stratification of the base flow. Weakly nonlinear stability equations are derived, under the assumption of fully developed flow conditions. Critical Rayleigh numbers and Landau coefficients are determined in terms of the Prandtl number and stratification parameter. It is found that critical disturbances are always two-dimensional, for stationary and oscillating instabilities as well. Alternatives are considered for the calculation of the Landau coefficient. Analysis reveals that unstationary instability is the preferred mode at the codimension point.     

Correction to: Bismuth Yttrium Oxide (Bi3YO6), A New Electrode Material For Asymmetric Aqueous Supercapacitors

Journal of Inorganic and Organometallic Polymers and Materials - The original version of this article unfortunately contained mistakes. In line 9 of the abstract, 5% should read as 2%. The...     

Evaluation of amines for the selective catalytic reduction (SCR) of NOx from diesel engine exhaust

With a view to developing onboard generation of selective reductants for NO_x removal from diesel engine exhaust we compared the performance of a primary, secondary and tertiary amine to NH₃ using a typical mini core NH₃-SCR catalyst. Primary amines with short hydrocarbon chains, e.g. CH₃NH₂ (maximum NO_x conversion, 50%) approached the NO_x conversion obtained using NH₃ (maximum NO_x conversion, 70%). Increasing the amine to NO_x ratio greater than 1 results in NO_x conversions closer to those of NH₃ (maximum NO_x conversion increased to 60%). Secondary and tertiary amines had smaller NO_x conversions as a function of temperature and the drop in NO and NO_x conversion decreased with increasing amine hydrogen substitution. Also, the maximum NO_x conversion for each reductant tends to move to a lower temperature as the degree of substitution increases.Unlike NH₃, the amines can react in the gas phase at temperatures within the range of diesel engine exhaust. Due to this gas phase reactivity the NO_x conversions measured using the mini core SCR catalyst also contain a gas phase conversion component. Gas phase conversions were investigated by replacing the mini core SCR catalyst with an equivalent length of quartz beads. Subtraction of the two results highlighted the differences between the mini core catalytic and gas phase conversions measured in this manner over the temperature range investigated. These differential NO_x conversions for the three amines had maxima at about 375 °C.     

Hydrothermal dissolution of willow in hot compressed water as a model for biomass conversion

Biomass has wide applications as a source of clean energy and as a raw material for different chemical stocks. Dissolution of willow as a model system for biomass conversion has been investigated in the 200–350 °C temperature range. The dissolution process was studied using a batch-type (diamond-anvil cell) and a continuous flow process reactor. A 95% dissolution of willow was achieved. The lignin and hemicellulose in willow were fragmented and dissolved at a temperature as low as 200 °C and a pressure of 10 MPa. Cellulose dissolved in the 280–320 °C temperature range. A dissolution mechanism is proposed, which involves a rapid fragmentation and hydrolysis of lignin, hemicellulose and cellulose to form oligomers and other water–soluble products, such as glucose. The re-condensation behavior of the dissolved oligomers is the main challenge for efficient dissolution. A continuous flow process is more effective and simpler in this regard than is a batch process. The results of this work show that hot, compressed water affords a viable alternative to corrosive chemicals and toxic solvents, thereby facilitating the utilization of biomass as a source of renewable fuel and chemical feedstocks.     

Improved electrochemical redox performance of 2,5-dimercapto-1,3,4-thiadiazole by poly(3-methoxythiophene)

High electrocatalytic activity of an electropolymerized film of poly(3-methoxythiophene) (PMOT) is reported toward the redox reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) as a promising cathode material for the lithium ion battery. Cyclic voltammetry showed improved electrochemical performance of DMcT on PMOT-coated Pt electrode, indicating accelerated redox kinetics. Moreover, charge-discharge tests exhibited higher discharge capacity and slower capacity fading of the PMOT-doped DMcT composite cathode compared with pure DMcT.     

Evolutionary digital twin: A new approach for intelligent industrial product development

To fulfill increasingly difficult and demanding tasks in the ever-changing complex world, intelligent industrial products are to be developed with higher flexibility and adaptability. Digital twin (DT) brings about a possible means, due to its ability to provide candidate behavior adjustments based on received “feedbacks” from its physical part. However, such candidate adjustments are deterministic, and thus lack of flexibility and adaptability. To address such problem, in this paper an extended concept – evolutionary digital twin (EDT) and an EDT-based new mode for intelligent industrial product development has been proposed. With our proposed EDT, a more precise approximated model of the physical world could be established through supervised learning, based on which the collaborative exploration for optimal policies via parallel simulation in multiple cyberspaces could be performed through reinforcement learning. Hence, more flexibility and adaptability could be brought to industrial products through machine learning (such as supervised learning and reinforcement learning) based self-evolution. As a primary verification of the effectiveness of our proposed approach, a case study has been carried out. The experimental results have well confirmed the effectiveness of our EDT based development mode.