Functional Janus Membranes:Promising Platform for Advanced Lithium Batteries and Beyond

Separators or electrolyte membranes are recognized as the key components to guarantee ion transport in rechargeable batteries.However,the ever-growing applications of the battery systems for diverse working environments bring new challenges,which require advanced battery membranes with high thermal stability,excellent mechanical strength,high voltage tolerance,etc.Therefore,it is highly desirable to design novel methods/concepts to solve the current challenges for battery membranes through understanding the mechanism of novel phenomena and electrochemical reactions in battery systems working under unconventional conditions.Recently,the new emerging Janus separators or electrolyte membranes with two or more distinct chemical/physical properties arising from their asymmetric structure and composition,are promising to address the above challenges via rational design of their targeted functionalities.To this end,in this review,we first briefly cover the current challenges of the traditional battery membrane for battery devices working in unconventional conditions.Then,the state-of-art developments of the rational design of Janus membranes to overcome the above challenges for diverse battery applications are summarized.Finally,we outline these latest developments,challenges,and future potential directions of the Janus membrane.Our review is aimed to provide basic guidance for developing functional separators or electrolyte membranes for advanced batteries.

Human ACE2-Functionalized Gold“Virus-Trap”Nanostructures for Accurate Capture of SARS-CoV-2 and Single-Virus SERS Detection

The current COVID-19 pandemic urges the extremely sensitive and prompt detection of SARS-CoV-2 virus.Here,we present a Human Angiotensin-converting-enzyme 2(ACE2)-functionalized gold“virus traps”nanostructure as an extremely sensitive SERS biosensor,to selectively capture and rapidly detect S-protein expressed coronavirus,such as the current SARS-CoV-2 in the contaminated water,down to the single-virus level.Such a SERS sensor features extraordinary 106-fold virus enrichment originating from high-affinity of ACE2 with S protein as well as“virus-traps”composed of oblique gold nanoneedles,and 109-fold enhancement of Raman signals originating from multi-component SERS effects.Furthermore,the identification standard of virus signals is established by machine-learning and identification techniques,resulting in an especially low detection limit of 80 copies mL^(−1) for the simulated contaminated water by SARS-CoV-2 virus with complex circumstance as short as 5 min,which is of great significance for achieving real-time monitoring and early warning of coronavirus.Moreover,here-developed method can be used to establish the identification standard for future unknown coronavirus,and immediately enable extremely sensitive and rapid detection of novel virus.

A 3D-printed molybdenum-containing scaffold exerts dual pro-osteogenic and anti-osteoclastogenic effects to facilitate alveolar bone repair

The positive regulation of bone-forming osteoblast activity and the negative feedback regulation of osteoclastic activity are equally important in strategies to achieve successful alveolar bone regeneration. Here, a molybdenum(Mo)-containing bioactive glass ceramic scaffold with solid-strut-packed structures(Mo-scaffold) was printed, and its ability to regulate pro-osteogenic and antiosteoclastogenic cellular responses was evaluated in vitro and in vivo. We found that extracts derived from Mo-scaffold(Moextracts) strongly stimulated osteogenic differentiation of bone marrow mesenchymal stem cells and inhibited differentiation of osteoclast progenitors. The identified comodulatory effect was further demonstrated to arise from Mo ions in the Mo-extract,wherein Mo ions suppressed osteoclastic differentiation by scavenging reactive oxygen species(ROS) and inhibiting mitochondrial biogenesis in osteoclasts. Consistent with the in vitro findings, the Mo-scaffold was found to significantly promote osteoblastmediated bone formation and inhibit osteoclast-mediated bone resorption throughout the bone healing process, leading to enhanced bone regeneration. In combination with our previous finding that Mo ions participate in material-mediated immunomodulation, this study offers the new insight that Mo ions facilitate bone repair by comodulating the balance between bone formation and resorption. Our findings suggest that Mo ions are multifunctional cellular modulators that can potentially be used in biomaterial design and bone tissue engineering.

One stone two birds:Vanadium doping as dual roles in self-reduced Pt clusters and accelerated water splitting

Integrating active Pt clusters into transition-metal oxides with water-dissociation ability is effective to prepare a bifunctional electrocatalyst for water splitting in alkaline.However,the additional utilization of a reductant and/or the operation at the elevating temperature causes the over-growth and agglomeration of Pt clusters,thus losing the high catalytic performance.Herein,we report that V dopant not only favors self-reducing Pt clusters on Ni Fe layered double hydroxide(LDH)(Pt/NiFeV)at room temperature,but also regulates interfacial charge redistribution to enhance the water-splitting performance.Experimental and theoretical studies reveal that V dopant into Ni Fe LDH triggers more electrons to transfer to adjacent Fe atoms,thus leading to a higher reducing ability compared to that without V-doping.When used as water-splitting electrocatalyst,V doping promotes electron loss of Pt clusters in Pt/Ni Fe V,optimizing the free energy of hydrogen adsorption and proton recombination kinetics at the cathode.Meanwhile,it also moves the d-band center of Ni away from the Fermi level to optimize the adsorption of*OH intermediates and facilitate the desorption of oxygen molecules at the anode.Thereby,Pt/Ni Fe V exhibits much higher bifunctional performance than V-free Pt/Ni Fe LDH toward both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).This work can spark inspiration of designing other bifunctional electrocatalysts for energy conversion and storage.

Nature-inspired materials and designs for flexible lithium-ion batteries

Flexible lithium-ion batteries(FLBs)are of critical importance to the seamless power supply of flexible and wearable electronic devices.However,the simultaneous acquirements of mechanical deformability and high energy density remain a major challenge for FLBs.Through billions of years of evolutions,many plants and animals have developed unique compositional and structural characteristics,which enable them to have both high mechanical deformability and robustness to cope with the complex and stressful environment.Inspired by nature,many new materials and designs emerge recently to achieve mechanically flexible and high storage capacity of lithiumion batteries at the same time.Here,we summarize these novel FLBs inspired by natural and biological materials and designs.We first give a brief introduction to the fundamentals and challenges of FLBs.Then,we highlight the latest achievements based on nature inspiration,including fiber-shaped FLBs,origami and kirigami-derived FLBs,and the nature-inspired structural designs in FLBs.Finally,we discuss the current status,remaining challenges,and future opportunities for the development of FLBs.This concise yet focused review highlights current inspirations in FLBs and wishes to broaden our view of FLB materials and designs,which can be directly“borrowed”from nature.

Module-level design and characterization of thermoelectric power generator

Thermoelectric power generation provides us the unique capability to explore the deep space and holds promise for harvesting the waste heat and providing a battery-free power supply for IoTs.The past years have witnessed massive progress in thermoelectric materials,while the module-level development is still lagged behind.We would like to shine some light on the module-level design and characterization of thermoelectric power generators(TEGs).In the module-level design,we review material selection,thermal management,and the determination of structural parameters.We also look into the module-level characterization,with particular attention on the heat flux measurement.Finally,the challenge in the optimal design and reliable characterization of thermoelectric power generators is discussed,together with a calling to establish a standard test procedure.

Honeycomb-like MoCo alloy on 3D nitrogen-doped porous graphene for efficient hydrogen evolution reaction

An efficient electrocatalyst is indispensable to significantly reduce energy consumption and accelerate the conversion efficiency of water splitting.In this work,the honeycomb-like porous MoCo alloy on nitrogen-doped three-dimensional(3D)porous graphene substrate(Mo_(0.3)Co_(0.7)@NPG)has been synthesized from the annealing of layered double hydroxide(MoCo-LDH@NPG).Especially,the Mo_(0.3)Co_(0.7)@NPG exhibits low hydrogen evolution overpotential of 75 mV(10 mA·cm^(-2))and a Tafel slope of 69.9 mV·dec^(-1),which can be attributed to highly conductive NPG substrate,the unique nanostructure and the synergistic effect of Mo and Co.Moreover,the Mo_(0.3)Co_(0.7)@NPG can maintain the original morphology and high catalytic activity after 50-h stability test.This work proposes a general strategy to synthesize a multi-element alloy on conductive substrates with high porosity for electrocatalytic reaction.

A combination therapy for androgenic alopecia based on quercetin and zinc/copper dual-doped mesoporous silica nanocomposite microneedle patch

A nanocomposite microneedle(ZCQ/MN)patch containing copper/zinc dual-doped mesoporous silica nanoparticles loaded with quercetin(ZCQ)was developed as a combination therapy for androgenic alopecia(AGA).The degradable microneedle gradually dissolves after penetration into the skin and releases the ZCQ nanoparticles.ZCQ nanoparticles release quercetin(Qu),copper(Cu^(2+))and zinc ions(Zn^(2+))subcutaneously to synergistically promote hair follicle regeneration.The mechanism of promoting hair follicle regeneration mainly includes the regulation of the main pathophysiological phenomena of AGA such as inhibition of dihydrotestosterone,inhibition of inflammation,promotion of angiogenesis and activation of hair follicle stem cells by the combination of Cu^(2+)and Zn^(2+)ions and Qu.This study demonstrates that the systematic intervention targeting different pathophysiological links of AGA by the combination of organic drug and bioactive metal ions is an effective treatment strategy for hair loss,which provides a theoretical basis for development of biomaterial based anti-hair loss therapy.

Realizing the highly reversible Zn^(2+)and Na^(+) dual ions storage in high-crystallinity nickel hexacyanoferrate microcubes for aqueous zinc-ion batteries

Prussian blue analogues(PBAs)with the 3D open framework are regarded as promising cathode candidates for aqueous Zinc ion batteries(ZIBs).Among various PBAs,nickel hexacyanoferrate(NiHCF)has attracted considerable attention because of its high operating voltage and economic merit.However,the cyclability of NiHCF is unsatisfactory due to poor structural stability during Zn^(2+) ions insertion/deinsertion.Moreover,the ion storage mechanism of NiHCF in aqueous electrolytes has not been fully revealed yet.Herein,high-crystallinity NiHCF(HC-NiHCF)microcubes with improved structural stability and larger crystal plane spacing are synthesized.For the first time,highly reversible Zn2+ions and Na+ions co-insertion/extraction are achieved for the HC-NiHCF microcubes in mixed aqueous electrolyte,as evidenced by various observations including two separated discharge plateaus and sequential changes of Na 1s and Zn 2p signals in ex-situ X-ray photoelectron spectroscopy(XPS).As a result,a high specific capacity of 73.9 mAh g^(−1) is obtained for the HC-NiHCF microcubes at 0.1 A g−1,combined with enhanced cycle stability(75%vs.16.4%)over 1000 cycles at 2 A g^(−1).The reversible Zn^(2+) ions and Na+ions co-insertion in HC-NiHCF microcubes reveals a new ion storage mechanism of Ni-based PBAs in aqueous electrolytes.

Nano-calcium silicate mineralized fish scale scaffolds for enhancing tendon-bone healing

Tendon-bone healing is essential for an effective rotator cuff tendon repair surgery,however,this remains a significant challenge due to the lack of biomaterials with high strength and bioactivity.Inspired by the high-performance exoskeleton of natural organisms,we set out to apply natural fish scale(FS)modified by calcium silicate nanoparticles(CS NPs)as a new biomaterial(CS-FS)to overcome the challenge.Benefit from its“Bouligand”microstructure,such FS-based scaffold maintained excellent tensile strength(125.05 MPa)and toughness(14.16 MJ/m^(3)),which are 1.93 and 2.72 times that of natural tendon respectively,allowing it to well meet the requirements for rotator cuff tendon repair.Additionally,CS-FS showed diverse bioactivities by stimulating the differentiation and phenotypic maintenance of multiple types of cells participated into the composition of tendon-bone junction,(e.g.bone marrow mesenchymal stem cells(BMSCs),chondrocyte,and tendon stem/progenitor cells(TSPCs)).In both rat and rabbit rotator cuff tear(RCT)models,CS-FS played a key role in the tendon-bone interface regeneration and biomechanical function,which may be achieved by activating BMP-2/Smad/Runx2 pathway in BMSCs.Therefore,natural fish scale-based biomaterials are the promising candidate for clinical tendon repair due to their outstanding strength and bioactivity.

Bifunctional oxygen electrocatalysts for rechargeable zinc-air battery based on MXene and beyond

Oxygen electrocatalysts are of great importance for the air electrode in zinc–air batteries(ZABs).Owing to large surface area,high electrical conductivity and ease of modification,two-dimensional(2D)materials have been widely studied as oxygen electrocatalysts for the rechargable ZABs.The elaborately modified 2D materials-based electrocatalysts,usually exhibit excellent performance toward the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),which have attracted extensive interests of worldwide researchers.Given the rapid development of bifunctional electrocatalysts toward ORR and OER,the latest progress of non-noble electrocatalysts based on layered double hydroxides(LDHs),graphene,and MXenes are intensively reviewed.The discussion ranges from fundamental structure,synthesis,electrocatalytic performance of these catalysts,as well as their applications in the rechargeable ZABs.Finally,the challenges and outlook are provided for further advancing the commercialization of rechargeable ZABs.

Carbon deficiency introduced plasticity of rock-salt-structured transition metal carbides

High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impedes their performance in aerodynamically harsh environments.In this work,a promising strategy is proposed to introduce plasticity in TaC–HfC solid solutions by manipulating carbon deficiency.The approach combines density-functional theory(DFT)with experiments and takes Pugh's ratio(k)as the criteria.Depletion of carbon atoms in TaC–HfC solid solutions results in the de-localizing of valence electrons,deviation of spatial modulus along different crystal plane directions,and leading to significant elastic anisotropy.The carbon deficient Ta_(0.8)Hf_(0.2)C_(0.8) is predicted to be a‘softer phase’with reduced modulus and Pugh's ratio(k=0.58).A series of Ta1–xHfxCy(x=0.2 and 0.8,y=0.8,0.9,and 1.0)bulk ceramics are experimentally fabricated by an excessive metal alloying method.Trigonal and hexagonal close-packed structured carbides are derived when the carbon deficiency y decreased to 0.7.The indentation modulus drops from 641.8±14.8 GPa for Ta_(0.8)Hf_(0.2)C_(1.0) to 555.8±9.9 GPa for Ta0.8Hf0.2C0.8.The specific stoichiometric composition of Ta_(0.8)Hf_(0.2)C_(0.8) is experimentally verified to possess both plasticity(k=0.41)and ultra-high nanohardness(41.3±1.3 GPa).

新型离子交换法制备具有高倍率和高强度钠离子存储性能的本征赝电容正极材料Na_(0.44)MnO_(2)

钠离子电池因其成本低、资源丰富等优点而成为新一代储能设备.在各种正极中,隧道型Na_(0.44)MnO_(2)因其较大的Na^(+)通道,被认为是快速充电电池的合适正极材料,但仍然存在Na^(+)动力学缓慢等问题.本文首次提出了一种Na_(0.44)MnO_(2)的新型离子交换方法,通过调节合成条件,可以很好地控制K^(+)残余量和Na_(0.44)MnO_(2)的尺寸.结果表明,Na_(0.44)MnO_(2)结构中的残留K^(+)扩大了Na^(+)的输运通道,小颗粒形貌缩短了Na^(+)的迁移距离,且晶体中的带状缺陷界面进一步加速了Na^(+)的输运.获得的Na_(0.44)MnO_(2)具有本征赝电容特性,在2-4 V和20 C电流下有79.0 mA h g^(-1)的优异倍率性能.长期循环测试表明,20 C下1000次循环的保持率为98.1%,0.5 C下200次循环的保持率为96.3%.本工作为用于快速充电储能装置的高倍率、高稳定性Na_(0.44)MnO_(2)正极的大规模生产提供了一条新途径.

通过引入天然氨基酸基团来设计高容量、长寿命钠离子电池用有机分子电极

有机电极具有结构可设计性强、容量大、可容纳大离子等优点.然而,在钠离子电池中,有机电极材料的容量仍然很低,且其在有机电解质中的高溶解度导致其寿命较短.如何通过化合物设计来提高其性能一直是研究人员关注的问题.本研究通过简单方法将氨基酸接枝到有机化合物上,提高了其容量和循环稳定性.首先,氨基酸之间的氢键使其形成更稳定的层状结构;氨基酸基团在有机电极材料和羧甲基纤维素粘合剂之间形成分子间相互作用,降低界面阻力,显著提高循环稳定性,使得钠离子电池循环次数超过2000次.其次,实验和计算结果表明,氨基酸基团提供了Na^(+)转运途径和额外的可逆存储位点,从而提高了比容量(~300 mA h g^(-1)).本策略可以启发未来钠离子电池的有机分子设计.

Thermoelectric interface materials:A perspective to the challenge of thermoelectric power generation module

The past years has observed a significantly boost of the thermoelectric materials in the scale of thermoelectric figure-of-merit,i.e.ZT,because of its promising application to harvest the widely distributed waste heat.However,the simplified thermoelectric materials'performance scale also shifted the focus of thermoelectric energy conversion technique from devices-related efforts to materials-level works.As a result,the thermoelectric devices-related works didn't get enough attention.The device-level challenges behind were kept unknown until recent years.However,besides the thermoelectric materials properties,the practical energy conversion efficiency and service life of thermoelectric device is highly determined by assembling process and the contact interface.In this perspective,we are trying to shine some light on the device-level challenge,and give a special focus on the thermoelectric interface materials(TEiM)between the thermoelectric elements and electrode,which is also known as the metallization layer or solder barrier layer.We will go through the technique concerns that determine the scope of the TEiM,including bonding strength,interfacial resistance and stability.Some general working principles are summarized before the discussion of some typical examples of searching proper TEiM for a given thermoelectric conversion material.

Strategies for constructing manganese-based oxide electrode materials for aqueous rechargeable zinc-ion batteries

Commercial lithium-ion batteries (LIBs) have been widely used in various energy storage systems. However, many unfavorable factors of LIBs have prompted researchers to turn their attention to the development of emerging secondary batteries. Aqueous zinc ion batteries (AZIBs) present some prominent advantages with environmental friendliness, low cost and convenient operation feature. MnO_(2) electrode is the first to be discovered as promising cathode material. So far, manganese-based oxides have made significant progresses in improving the inherent capacity and energy density. Herein, we summarize comprehensively recent advances of Mn-based compounds as electrode materials for ZIBs. Especially, this review focuses on the design strategies of electrode structures, optimization of the electrochemical performance and the clarification of energy storage mechanisms. Finally, their future research directions and perspective are also proposed.

Introducing sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction in SnS_(2) nanosheets to promote photocatalytic activity

Due to the relatively sluggish charge carrier separation in metal sulfides,the photocatalytic activity of them is still far lower than expected.Herein,sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction were successfully introduced into the SnS_(2) nanosheets through high energy ball-milling.These defective structures were studied by the electron paramagnetic resonance,Raman spectra,X-ray photoelectron spectroscopy,and high-resolution transmission electron microscope analyses.The sulfur vacancies and in-plane heterojunctions strongly accelerate the separation of photoexcited electron-hole pairs,as confirmed by the photo luminesce nce emission spectra and time-resolved photoluminescence decay spectra.The introduction of sulfur vacancies and in-plane heterojunction in SnS_(2) nanosheets results in roughly six times higher photodegrading rate for methyl orange and four times higher photocatalytic reduction rate of Cr6+than those of pure SnS_(2) nanosheets.

Effect of micro/nano-sheet array structures on the osteo-immunomodulation of macrophages

The immune response induced by surface topography crucially determines the implant success.However,how the immune response is mediated by the size of surface topography remains unclear.Hence,various biocompatible Mg-Al layered double hydroxides sheet-array films with different sizes(nano,micro and nano/micro mixture)were constructed on the biomedical titanium,and their osteo-immunomodulation effects on the macrophages were explored.The nano-sheet array structures significantly promoted the polarization of M2 macrophages by activating the PI3K-AKT-mTOR signaling pathway with high gene expressions of integrin b2 and FAK.While the micro-sheet array structures enhanced osteogenic differentiation of mouse bone marrow mesenchymal stem cells(mBMSCs)via ROCK-YAP/TAZ-mediated mechanotransduction.Moreover,the nano-sheet array structures promoted the osteogenic differentiation of mBMSCs with a high proportion of M2 macrophages through a shared medium.This study gave further information concerning integrin-induced focal adhesions in cells of different sheet array structures and their role in macrophage polarization and osteogenic differentiation of mBMSCs,which might help to design biomaterial surfaces with optimal geometry for a desired immunemodulation.

[Cs_(6)Cl][Ga_(5)GeQ_(12)](Q=S,Se):two novel porous layered chalcohalides exhibiting two-band emission and ion exchange properties

The salt-inclusion materials have drawn significant attention for their manifold structural chemistry and novel physical/chemical properties.Herein,two new salt-inclusion chalcohalides,[Cs_(6)Cl][Ga_(5)GeQ_(12)](Q=S,Se),have been discovered via hightemperature flux methods.The two isostructural compounds are constructed by porous[Ga_(5)GeQ_(12)]^(5−)layers with[ClCs_(6)]^(5+)octahedra filled in the holes.The[Ga_(5)GeQ_(12)]^(5−)layer is composed of the honeycomb-like(Ga/Ge)_(18)Q_(42)rings containing(Ga/Ge)_(3)Q_(9)trimer as basic unit.The band gaps of the two compounds are 3.90 and 2.89 eV,respectively.[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits interesting two-band emission properties which are related to the intermediate-band electronic structure revealed by density functional theory(DFT)calculations.Owing to the porous layered structure,[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits topological ion exchange ability towards Cd^(2+)ions with the maximum sorption capacity of 250 mg/g and high distribution coefficient(Kd)near 106 mL/g.This work further enriches the structural diversity of salt-inclusion materials and extends their potential application range to ion exchange adsorption.

Creep behavior and post-creep thermoelectric performance of the n-type Skutterudite alloy Yb_(0.3)Co_(4)Sb_(12)

Upon uniaxial compressive loading at 500℃(T/Tm=0.67,where Tm is the absolute melting point),the n-type Skutterudite alloy Yb03Co4Sb12 deforms plastically by creep via a power-law,with a stress exponent~3 consistent with dislocation viscous glide.An activation energy of 171 kJ/mol is measured over the temperature range of 500-587℃(T/Tm=0.67-0.75)at a stress of 30 MPa.Yb_(0.3)Co_(4)Sb_(12)is ductile at 500℃,exhibiting a compressive strain of 25%when subjected to stresses ranging from 22 to 90 MPa for up to 28 days.Among the thermoelectric materials tested so far for creep,Yb_(0.3)Co_(4)Sb_(12)exhibits a creep resistance intermediate between low-melting(Bi2Te3,TAGS-85)and high-melting thermoelectrics(Mg2Si and ZrNiSn).A relatively modest drop in the figure of merit zT,from 0.67 to 0.52,is displayed by Yb_(0.3)Co_(4)Sb_(12)after accumulating 3.7%compressive creep strain at 500℃,mostly due to a drop in electrical conductivity.