Advancing oxygen separation:insights from experimental and computational analysis of La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)oxygen transport membranes

In this study,perovskite-type La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)powders were synthesized using a scalable reverse co-precipitation method,presenting them as novel materials for oxygen transport membranes.The comprehensive study covered various aspects including oxygen permeability,crystal structure,conductivity,morphology,CO_(2) tolerance,and long-term regenerative durability with a focus on phase structure and composition.The membrane La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)exhibited high oxygen permeation fluxes,reaching up to 0.88 and 0.64 mL·min^(−1)·cm^(−2) under air/He and air/CO_(2) gradients at 1173 K,respectively.After 1600 h of CO_(2) exposure,the perovskite structure remained intact,showcasing superior CO_(2) resistance.A combination of first principles simulations and experimental measurements was employed to deepen the understanding of Cu/Zn substitution effects on the structure,oxygen vacancy formation,and transport behavior of the membranes.These findings underscore the potential of this highly CO_(2)-tolerant membrane for applications in high-temperature oxygen separation.The enhanced insights into the oxygen transport mechanism contribute to the advancement of next-generation membrane materials.

Recent advances in self-healing hydrogel composites for flexible wearable electronic devices

Flexible electronic devices with mechanical properties like the soft tissues of human organs have great potential for the next generation of wearable and implantable electronic devices.Self-healing hydrogel composites typically have high tensile strength,high electrical conductivity and damage repair properties and have wide applications in flexible electronics,such as human-computer interaction,health detection and soft robots.Various self-healing hydrogel composites have been developed to produce new stretchable conductive materials with satisfactory mechanical and selfhealing properties.This paper presents the fabrication of self-healing hydrogel composites and their application in flexible electronic devices.Firstly,the repair mechanism of physically cross-linked and chemically cross-linked self-healing hydrogel composites is presented.Secondly,self-healing double network hydrogels,self-healing nanocomposite hydrogels and double crosslinked self-healing hydrogel composites and their applications in flexible sensors,energy harvesting devices,energy storage devices and optical devices are presented and discussed.Finally,the challenges and prospects of self-healing hydrogel composites in flexible electronic devices in the future are presented.

Tailoring thermoelectric properties of Zr(0.43)Hf(0.57)NiSn half-Heusler compound by defect engineering

The thermoelectric transport properties of Zr0.43Hf0.57 NiSn half-Heusler compounds were investigated for samples sintered with different spark plasma sintering(SPS)periods:8,32 and 72 min.By means of scanning transmission electron microscopy with a highangular annular dark-field detector(STEM-HAADF),it was found that sintering time affected the defect concentration,namely the amount of Ni interstitial atoms,and created locally ordered inclusions of full-Heusler phase.The structural information,phase composition and electrical transport properties could be consistently explained by the assumption that Ni interstitials give rise to an impurity band situated about 100 meV below the bottom of the conduction band via a self-doping behavior.The impurity band was found to merge with the conduction band for the sample with intermediate SPS time.The effect was ascribed to the gradual dissolution of full-Heusler phase inclusions and production of interstitial Ni defects,which eventually vanished for the sample with the longest sintering time.It was demonstrated that the modification of the density of states near the edge of the conduction band and enhanced overall charge carrier concentration provided by defect engineering led to overall 26%increase in the thermoelectric figure of merit(ZT)with respect to the other samples.

Multifunctional antiperovskites driven by strong magnetostructural coupling

Based on density functional theory calculations,we elucidated the origin of multifunctional properties for cubic antiperovskites with noncollinear magnetic ground states,which can be attributed to strong isotropic and anisotropic magnetostructural coupling.Of 54 stable magnetic antiperovskites M_(3)XZ(M=Cr,Mn,Fe,Co,and Ni;X=selected elements from Li to Bi except for noble gases and 4f rare-earth metals;and Z=C and N),14 are found to exhibit the Γ_(4g)/Γ_(5g)(i.e.,characterized by irreducible representations)antiferromagnetic magnetic configurations driven by frustrated exchange coupling and strong magnetocrystalline anisotropy.Using the magnetic deformation as an effective proxy,the isotropic magnetostructural coupling is characterized,and it is observed that the paramagnetic state is critical to understand the experimentally observed negative thermal expansion and to predict the magnetocaloric performance.Moreover,the piezomagnetic and piezospintronic effects induced by biaxial strain are investigated.It is revealed that there is not a strong correlation between the induced magnetization and anomalous Hall conductivities by the imposed strain.Interestingly,the anomalous Hall/Nernst conductivities can be significantly tailored by the applied strain due to the fine-tuning of the Weyl points energies,leading to promising spintronic applications.