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Aluminum-sulfur batteries (ASBs) are deemed to be alternatives to meet the increasing demands for energy storage due to their high theoretical capacity, high safety, low cost, and the rich abundances of Al and S. However, the challenging problems including sluggish conversion kinetics, inferior electrolyte compatibility, and potential dendrite formation are still remained. This review comprehensively focuses on summarizing the specific strategies from polysulfide shuttling inhibition to form smooth anodic Al activation/ deposition. Especially, innovations in cathodic side for achieving electrochemical kinetic modulations, electrolyte optimizations, and anodic interface mediations are discussed. Upon detailed elaborating the formation process, influencing factors, and their interactions in the Al-S electrochemistry, a comprehensive summary of their causative mechanisms and the corresponding strategies are provided, including optimization of electrolytes, innovative in situ detections, and precise electrocatalytic strategies. Based on such a systematic understanding in the Al-S electrochemistry, the possible electrochemical reaction mechanism is deciphered more clearly and enlightened practical strategies on the future development of stable ASBs. Furthermore, future opportunities and directions of high-performance conversion-based Al-S batteries for large-scale energy storage applications are highlighted. [ABSTRACT FROM AUTHOR]

Lithium metal is considered as the most prospective electrode for next‐generation energy storage systems due to high capacity and the lowest potential. However, uncontrollable spatial growth of lithium dendrites and the crack of solid electrolyte interphase still hinder its application. Herein, Schottky defects are motivated to tune the 4f‐center electronic structures of catalysts to provide active sites to accelerate Li transport kinetics. As experimentally and theoretically confirmed, the electronic density is redistributed and affected by the Schottky defects, offering numerous active catalytic centers with stronger ion diffusion capability to guide the horizontal lithium deposition against dendrite growth. Consequently, the Li electrode with artificial electronic‐modulation layer remarkably decreases the barriers of desolvation, nucleation, and diffusion, extends the dendrite‐free plating lifespan up to 1200 h, and improves reversible Coulombic efficiency. With a simultaneous catalytic effect on the conversions of sulfur species at the cathodic side, the integrated Li–S full battery exhibits superior rate performance of 653 mA h g−1 at 5 C, high long‐life capacity retention of 81.4% at 3 C, and a high energy density of 2264 W h kg−1 based on sulfur in a pouch cell, showing the promising potential toward high‐safety and long‐cycling lithium metal batteries. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries exhibit unparalleled merits in theoretical energy density (2600 W h kg−1) among next‐generation storage systems. However, the sluggish electrochemical kinetics of sulfur reduction reactions, sulfide oxidation reactions in the sulfur cathode, and the lithium dendrite growth resulted from uncontrollable lithium behaviors in lithium anode have inhibited high‐rate conversions and uniform deposition to achieve high performances. Thanks to the "adsorption‐catalysis" synergetic effects, the reaction kinetics of sulfur reduction reactions/sulfide oxidation reactions composed of the delithiation of Li2S and the interconversions of sulfur species are propelled by lowering the delithiation/diffusion energy barriers, inhibiting polysulfide shuttling. Meanwhile, the anodic plating kinetic behaviors modulated by the catalysts tend to uniformize without dendrite growth. In this review, the various active catalysts in modulating lithium behaviors are summarized, especially for the defect‐rich catalysts and single atomic catalysts. The working mechanisms of these highly active catalysts revealed from theoretical simulation to in situ/operando characterizations are also highlighted. Furthermore, the opportunities of future higher performance enhancement to realize practical applications of lithium–sulfur batteries are prospected, shedding light on the future practical development. [ABSTRACT FROM AUTHOR]

Flexible materials and devices that can simultaneously reflect multimodal information are highly desired for novel flexible electronics and intelligent flexible sensing systems. In this regard, flexible magnetic films have great potential for wireless multimodal flexible sensor due to the curvature and azimuth angle‐dependent ferromagnetic resonance. However, a key challenge now is to build the precise relationship among the mechanical bending, azimuth angle, and the ferromagnetic resonance of the film, which involves multi‐physics and coupled process. In this work, the physical problem is solved by combining material engineering and machine learning. Material domain engineering is applied to form localized multi‐peak ferromagnetic resonance features for increasing sensitivity. Besides, convolutional neural network algorithm is utilized to help recognize the bending and azimuth angle modulated ferromagnetic resonance in flexible film systems. It is found that the bending information for the flexible film with engineered domain structure can be mapped to the ferromagnetic profile with accuracy over 99%, while the accuracy sharply decreases to less than 50% in the control group of high‐quality film. This study provides a versatile platform for developing machine learning‐based novel sensing materials. [ABSTRACT FROM AUTHOR]

GdVO4 : Eu3+ nanophosphors co‐doped with alkali metal ions (Li+, Na+, K+) of various concentrations were fabricated by an efficient hydrothermal method. The microstructure and luminescent emission properties were tested systematically. The results demonstrated that the co‐doping of M+ led to lattice distortion, which is closely related to dopants' ionic radii and concentrations. The lattice distortion further resulted in a fluctuation of luminescent brightness. The optimal luminescent properties of GdVO4 : Eu3+ co‐doped with Li+(10 atom‐% (at. %)), Na+(8 at. %), K+(6 at. %) were achieved respectively. Among them, the GdVO4 : Eu3+ co‐doped with Li+ of 10 at % possessed the highest emission intensity. Moreover, the alkali metal ions co‐doping also gave rise to the elevation of the concentration quenching threshold of Eu3+, which further enhanced the luminescent performance. [ABSTRACT FROM AUTHOR]

The nickel‐rich LiNi0.91Co0.06Al0.03O2 cathode material has attracted wide attention due to its high energy density and appropriate thermal stability; however, its practical application has been greatly restricted by exorbitant residual LiOH/Li2CO3 and poor cycling performance. In this work, we have reduced the residual LiOH/Li2CO3 by washing the LiNi0.91Co0.06Al0.03O2 fabricated through a high‐temperature solid‐state method and improved the cycling performance with a composite coating process. The results show that the amount of residual LiOH/Li2CO3 in the washed materials is significantly decreased, which is very favorable for the processability of materials. LiNi0.91Co0.06Al0.03O2 with 0.1 wt% composite coating exhibits optimum properties: the discharge capacity reaches 217.4 mAh/g at 0.1 C, the cycling retention still remains at 93.7 % after 100 cycles at 1 C, and the cycling retention of the soft‐packing battery remains as high as 81.7 % after 800 cycles at 1 C. The excellent electrochemical performances are attributed to the synergistic effect of excellent fluidity of H3BO3 and outstanding stability of Y2O3, mitigating the interface reaction between electrolyte and cathode material. [ABSTRACT FROM AUTHOR]

Willow catkin was selected as raw material to fabricated carbon matrix in cathode of lithium‐sulfur (Li−S) battery due to its unique tubular morphology. The effects of activation time on the microstructure and electrochemical properties were investigated. The direct pyrolysis product inherited the tube‐like morphology. After activated by KOH under high temperature once, the microtubes were shorten and pressed as ribbon‐like. Meanwhile abundant micropores were formed in the tube wall. Further activatated the product twice, the original tube‐like microstructure was collapsed. Thus the results demonstrated that extending the activation time greatly affected the microstructure of carbon product. Furthermore, the sample activated once exhibited the largest specific surface area of 2033.09 m2 g−1 and the largest sulfur loading ratio (71.1 %). Moreover, the suitable activated sample exhibited the highest specific discharge capacity (1365.8 mAh g−1) and the best cycling performance. Consequently, the activation process played an important role in the microstructure and electrochemical performance of catkin derived carbon matrix in Li−S battery. [ABSTRACT FROM AUTHOR]

Rechargeable lithium−sulfur (Li−S) batteries with high areal capacity are hindered by the ion/electron pathway and sluggish reaction kinetics of sulfur species, resulting from high energy barriers. Inspired by the nature of biomass and efficient nutrition transfer, we present a high‐performance sulfur cathode based on nanocarbon tunnels with natural polar catalytic sites. The inherited tunnels can propel lithium‐ion transport across the interface to reach the active materials and the interior heteroatom dopants provide abundant catalytic sites to further reduce the energy barriers. The as‐fabricated sulfur cathode displays much higher rate performance of 565 mA h g−1 at 6 C and a low decay rates of 0.029 % per cycle for 2000 cycles at 3 C. Most importantly, a high initial areal capacity of 5.1 mA h cm−2 with enhanced loading up to 5.8 mg cm−2 at 1 C is achieved, corresponding to volumetric capacity of 638 A h L−1. [ABSTRACT FROM AUTHOR]

With the development of flexible electronics, the mechanical flexibility of functional materials is becoming one of the most important factors that needs to be considered in materials selection. Recently, flexible epitaxial nanoscale magnetic materials have attracted increasing attention for flexible spintronics. However, the knowledge of the bending coupled dynamic magnetic properties is poor when integrating the materials in flexible devices, which calls for further quantitative analysis. Herein, a series of epitaxial LiFe5O8 (LFO) nanostructures are produced as research models, whose dynamic magnetic properties are characterized by ferromagnetic resonance (FMR) measurements. LFO films with different crystalline orientations are discussed to determine the influence from magnetocrystalline anisotropy. Moreover, LFO nanopillar arrays are grown on flexible substrates to reveal the contribution from the nanoscale morphology. It reveals that the bending tunability of the FMR spectra highly depends on the demagnetization field energy of the sample, which is decided by the magnetism and the shape factor in the nanostructure. Following this result, LFO film with high bending tunability of microwave magnetic properties, and LFO nanopillar arrays with stable properties under bending are obtained. This work shows guiding significances for the design of future flexible tunable/stable microwave magnetic devices. Nanoscale flexible lithium ferrite with bending tunable/stable ferromagnetic resonance is fabricated. The bending tunability of the resonance field highly depends on the magnetic anisotropy of materials and can be predicted by simulations. The results provide guiding significances for the design of future bending tunable/stable microwave magnetic devices. [ABSTRACT FROM AUTHOR]

For flexible materials, knowledge of the bending coupled physical properties is very important for designing devices. In article number 1800855, Ming Liu and co‐workers discuss a strategy to modulate the bending coupled microwave magnetism in epitaxial nanostructures. It is revealed that fabricating nanopillar arrays can be a good choice for flexible devices with stable properties under bending, while high‐quality film can be applied in tunable devices. [ABSTRACT FROM AUTHOR]