Layered Oxide Cathode for Potassium‐Ion Battery: Recent Progress and Prospective

Rechargeable potassium‐ion batteries (KIBs) have demonstrated great potential as alternative technologies to the currently used lithium‐ion batteries on account of the competitive price and low redox potential of potassium which is advantageous to applications in the smart grid. As the critical component determining the energy density, appropriate cathode materials are of vital need for the realization of KIBs. Layered oxide cathodes are promising candidates for KIBs due to high reversible capacity, appropriate operating potential, and most importantly, facile and easily scalable synthesis. In light of this trend, the recent advancements and progress in layered oxides research for KIBs cathodes, covering material design, structural evolution, and electrochemical performance are comprehensively reviewed. The structure–performance correlation and some effective optimization strategies are also discussed. Furthermore, challenges and prospects of these layered cathodes are included, with the purpose of providing fresh impetus for future development of these materials for advanced energy storage systems.     

Chemical‐to‐Electricity Carbon: Water Device

The ability to release, as electrical energy, potential energy stored at the water:carbon interface is attractive, since water is abundant and available. However, many previous reports of such energy converters rely on either flowing water or specially designed ionic aqueous solutions. These requirements restrict practical application, particularly in environments with quiescent water. Here, a carbon‐based chemical‐to‐electricity device that transfers the chemical energy to electrical form when coming into contact with quiescent deionized water is reported. The device is built using carbon nanotube yarns, oxygen content of which is modulated using oxygen plasma‐treatment. When immersed in water, the device discharges electricity with a power density that exceeds 700 mW m^?2, one order of magnitude higher than the best previously published result. X‐ray absorption and density functional theory studies support a mechanism of operation that relies on the polarization of sp² hybridized carbon atoms. The devices are incorporated into a flexible fabric for powering personal electronic devices.     

2D Metal Oxyhalide‐Derived Catalysts for Efficient CO2 Electroreduction

Electrochemical reduction of CO₂ is a compelling route to store renewable electricity in the form of carbon‐based fuels. Efficient electrochemical reduction of CO₂ requires catalysts that combine high activity, high selectivity, and low overpotential. Extensive surface reconstruction of metal catalysts under high productivity operating conditions (high current densities, reducing potentials, and variable pH) renders the realization of tailored catalysts that maximize the exposure of the most favorable facets, the number of active sites, and the oxidation state all the more challenging. Earth‐abundant transition metals such as tin, bismuth, and lead have been proven stable and product‐specific, but exhibit limited partial current densities. Here, a strategy that employs bismuth oxyhalides as a template from which 2D bismuth‐based catalysts are derived is reported. The BiOBr‐templated catalyst exhibits a preferential exposure of highly active Bi () facets. Thereby, the CO₂ reduction reaction selectivity is increased to over 90% Faradaic efficiency and simultaneously stable current densities of up to 200 mA cm^?2 are achieved—more than a twofold increase in the production of the energy‐storage liquid formic acid compared to previous best Bi catalysts.     

Ultrathin Porous NiFeV Ternary Layer Hydroxide Nanosheets as a Highly Efficient Bifunctional Electrocatalyst for Overall Water Splitting

Herein, the hydrothermal synthesis of porous ultrathin ternary NiFeV layer double hydroxides (LDHs) nanosheets grown on Nickel foam (NF) substrate as a highly efficient electrode toward overall water splitting in alkaline media is reported. The lateral size of the nanosheets is about a few hundreds of nanometers with the thickness of ≈10 nm. Among all molar ratios investigated, the Ni_0.75Fe_0.125V_0.125‐LDHs/NF electrode depicts the optimized performance. It displays an excellent catalytic activity with a modest overpotential of 231 mV for the oxygen evolution reaction (OER) and 125 mV for the hydrogen evolution reaction (HER) in 1.0 m KOH electrolyte. Its exceptional activity is further shown in its small Tafel slope of 39.4 and 62.0 mV dec^?1 for OER and HER, respectively. More importantly, remarkable durability and stability are also observed. When used for overall water splitting, the Ni_0.75Fe_0.125V_0.125‐LDHs/NF electrodes require a voltage of only 1.591 V to reach 10 mA cm^?2 in alkaline solution. These outstanding performances are mainly attributed to the synergistic effect of the ternary metal system that boosts the intrinsic catalytic activity and active surface area. This work explores a promising way to achieve the optimal inexpensive Ni‐based hydroxide electrocatalyst for overall water splitting.     

Microwave synthesis and voltammetric simultaneous determination of paracetamol and caffeine using an MOF-199-based electrode

In the present paper, the microwave synthesis of MOF-199 and its application as an electrode modifier for the simultaneous voltammetric determination of paracetamol (PAR) and caffeine (CAF) were demonstrated. The obtained materials were characterised by X-ray diffraction, a scanning electron microscope (SEM), nitrogen adsorption/desorption isotherms and thermal gravity. The microwave (MW) synthesis of MOF-199 has been compared to its conventional hydrothermal synthesis. It is found that by using the MW synthesis, MOF-199 can be obtained in a much shorter synthesis time with improved yield and textural properties. The electrode modified by MOF-199 was used in order to develop an electroanalytical method that can be used to simultaneously quantify PAR and CAF. The kinetic parameters of the electrode reaction process were also investigated. This proposed method was successfully employed for the simultaneous detection of PAR and CAF in pharmaceutical formulations using the standard addition method and the obtained results compared with the results determined by means of HPLC were found to be statistically similar.     

A damage to crack transition model accounting for stress triaxiality formulated in a hybrid nonlocal implicit discontinuous Galerkin‐cohesive band model framework

Modelling the entire ductile fracture process remains a challenge. On the one hand, continuous damage models succeed in capturing the initial diffuse damage stage but are not able to represent discontinuities or cracks. On the other hand, discontinuous methods, as the cohesive zones, which model the crack propagation behaviour, are suited to represent the localised damaging process. However, they are unable to represent diffuse damage. Moreover, most of the cohesive models do not capture triaxiality effect. In this paper, the advantages of the two approaches are combined in a single damage to crack transition framework. In a small deformation setting, a nonlocal elastic damage model is associated with a cohesive model in a discontinuous Galerkin finite element framework. A cohesive band model is used to naturally introduce a triaxiality‐dependent behaviour inside the cohesive law. Practically, a numerical thickness is introduced to recover a 3D state, mandatory to incorporate the in‐plane stretch effects. This thickness is evaluated to ensure the energy consistency of the method and is not a new numerical parameter. The traction‐separation law is then built from the underlying damage model. The method is numerically shown to capture the stress triaxiality effect on the crack initiation and propagation.     

A Literature Review of Supply Chain Collaboration Mechanisms and Their Impact on Performance

This article contributes a comprehensive literature review fulfilling the identified need for a systematic empirical study examining how well the mechanisms of supply chain collaboration (SCC) correspond with performance. A review of articles during the period of 2000–2017 reveals fundamental trends in adopted methodologies, scopes of SCC, and areas of performance. However, limited research focused on qualitative and simulation-based research in specific industries and geographic sections was found. A need for additional research on horizontal and internal collaboration, elements of power dependence in the relationship with performance, and the effects of SCC mechanisms on environmental and social performance was identified. This article contributes a maturity model for SCC that provides guidance to engineering managers to develop a roadmap for effectively implementing and improving the SCC process. The article suggests that engineering managers may benefit from examining case studies and the systems dynamics tool to explore how different collaboration levels lead to various performance outcomes in future.     

Effects of Si,Mn, and water vapour on the microstructure of protective scales grown on Fe–20Cr in CO2 gas

Abstract

Model alloys Fe–20Cr–0.5Si and Fe–20Cr–2Mn (wt-%) were exposed to Ar–20CO₂ and Ar–20CO₂–20H₂O at either 818 or 650°C. In dry gas, protective scales on Fe–20Cr–0.5Si consisted of an outer Cr₂O₃ layer and an inner SiO₂ layer. In wet gas, additional chromia whiskers were formed on top of the duplex scale. Chromia grains formed in wet gas were much smaller than those in dry gas. A TEM analysis revealed that phase constitutions of the protective scale on Fe–20Cr–2Mn were not uniform: Mn₃O₄ and MnCr₂O₄ above alloy grain boundaries and Mn₃O₄, Cr₂O₃ and MnCr₂O₄ on alloy grains. Formation of different oxides and morphologies are discussed in terms of changes in diffusion paths and thermodynamics caused by the presence of carbon and hydrogen.     

Hydration-Effect-Promoting Ni–Fe Oxyhydroxide Catalysts for Neutral Water Oxidation

Oxygen evolution reaction (OER) catalysts that function efficiently in pH-neutral electrolyte are of interest for biohybrid fuel and chemical production. The low concentration of reactant in neutral electrolyte mandates that OER catalysts provide both the water adsorption and dissociation steps. Here it is shown, using density functional theory simulations, that the addition of hydrated metal cations into a Ni–Fe framework contributes water adsorption functionality proximate to the active sites. Hydration-effect-promoting (HEP) metal cations such as Mg²⁺ and hydration-effect-limiting Ba²⁺ into Ni–Fe frameworks using a room-temperature sol–gel process are incorporated. The Ni–Fe–Mg catalysts exhibit an overpotential of 310 mV at 10 mA cm⁻² in pH-neutral electrolytes and thus outperform iridium oxide (IrO₂) electrocatalyst by a margin of 40 mV. The catalysts are stable over 900 h of continuous operation. Experimental studies and computational simulations reveal that HEP catalysts favor the molecular adsorption of water and its dissociation in pH-neutral electrolyte, indicating a strategy to enhance OER catalytic activity.     

Real-time and robust multiple-view gender classification using gait features in video surveillance

Pattern Analysis and Applications - It is common to view people in real applications walking in arbitrary directions, holding items, or wearing heavy coats. These factors are challenges in...