Chitosan/Sodium Alginate Multilayer pH-Sensitive Films Based on Layer-by-Layer Self-Assembly for Intelligent Packaging

The abuse of plastic food packaging has brought about severe white pollution issues around the world.Developing green and sustainable biomass packaging is an effective way to solve this problem.Hence,a chitosan/sodium alginate-based multilayer film is fabricated via a layer-by-layer(LBL)self-assembly method.With the help of superior interaction between the layers,the multilayer film possesses excellent mechanical properties(with a tensile strength of 50 MPa).Besides,the film displays outstanding water retention property(blocking moisture of 97.56%)and ultraviolet blocking property.Anthocyanin is introduced into the film to detect the food quality since it is one natural plant polyphenol that is sensitive to the pH changes ranging from 1 to 13 in food when spoilage occurs.It is noted that the film is also bacteriostatic which is desired for food packaging.This study describes a simple technique for the development of advanced multifunctional and fully biodegradable food packaging film and it is a sustainable alternative to plastic packaging.

Bifunctional Liquid Metals Allow Electrical Insulating Phase Change Materials to Dual-Mode Thermal Manage the Li-Ion Batteries

Phase change materials(PCMs)are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries(LIBs)according to real-time thermal conditions,guaranteeing the reliable operation of LIBs in both cold and hot environments.Herein,we report a liquid metal(LM)modified polyethylene glycol/LM/boron nitride PCM,capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction.Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB’s structure and heat-conduction characteristic.Typically,soft and deformable LMs are modified on the boron nitride surface,serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m^(−1) K^(−1) in the vertical and in-plane directions,respectively.In addition,LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system.As a proof-of-concept,this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10℃ at high charging/discharging rate,opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway.

Harnessing the Unique Features of 2D Materials toward Dendrite-free Metal Anodes

Electrochemically active metal anodes,such as lithium,sodium,potassium,and zinc,have attracted great research interests in the advanced rechargeable batteries owing to their superior theoretical energy densities.Unfortunately,the metal anodes suffer from the huge volume changes with loss of active materials during the plating and stripping processes,resulting in fast capacity decay.Moreover,the random growth of dendrites on the metal anodes will penetrate the separator,causing severe safety issues.Engineering metal anodes by introducing the 2D materials are widely investigated to alleviate these issues.Benefitting from the ultrathin structure feature and unique electrical properties,2D materials are regarded as one of the best host of metal anodes.Besides,the tunable active sites on basal plane enable 2D materials to achieve favorable interaction with metal anodes.Moreover,some 2D materials exhibit good mechanical strength and flexibility,serving as building block for the artificial solid electrolyte interphase.In this review,we mainly disclosed the correlations between the intrinsic properties of 2D materials and their functions in guiding uniform nucleation,controlling the growth of metals,and accommodating the volume change.Also,the challenges of 2D materials in metal anodes are well discussed.Finally,the future directions to develop highperformance metal anodes by taking advantage of these unique features of 2D materials are proposed.

原位重构限制在三维纳米孔铜内的铋纳米颗粒促电还原CO_(2)

由于单金属Bi在CO_(2)还原反应(CO_(2)RR)中效率较低,通过表面工程复合材料提高电导率和产率是一种有吸引力的方法.在此,我们重构了在三维纳米孔铜结构中的原位生长金属Bi纳米颗粒.得益于三维纳米多孔导电网络和Cu与Bi之间的强相互作用,Bi@np-Cu费米能级向上移动,表现出优异的电催化二氧化碳还原性能.Bi@np-Cu在-0.97 V的电位下具有97.7%的甲酸法拉第效率,电流密度为82 mA cm^(-2).重要的是,该催化剂在连续催化反应40 h后仍能实现超过90%的法拉第效率.DFT计算表明,np-Cu有效地调节了Bi的电子态,优化了中间吸附能,从而提高了Bi的本征活性.这项工作为纳米多孔金属在催化中的应用提供了一个新视角.

Self-cleaning SERS sensor based on flexible Ni_(3)S_(2)/MoS_(2)@Ag@PDMS composites for label-free multiplex volatile organic compounds detection

Flexible self-cleaning surface-enhanced Raman scattering(SERS)sensors are highly desirable for the detection of various environmental pollutants,including volatile organic compounds(VOCs).However,achieving sensitive detection without labeling and ensuring efficient cyclic use remain significant challenges.Herein,we introduce a direct approach to create a versatile Ni_(3)S_(2)/MoS_(2)@Ag@PDMS(PDMS=polydimethylsiloxane)composite SERS substrate using chemical vapor deposition technology.The produced substrate shows outstanding performance,offering extremely low detection sensitivity(1.0×10^(−12)M 4-aminobenzenethiol)and high enhancement factors(approximately 107).The interactions between the rod-shaped Ni_(3)S_(2)/MoS_(2)@Ag heterostructure and the molecules facilitate the transfer of charge,resulting in an increased electric field enhancement of the exciton resonance.This has the dual benefit of providing a self-cleaning effect and enhancing SERS efficiency.Importantly,the substrate enables sensitive detection of VOCs gas molecules without the need for labels,achieving a minimum detectable concentration as low as 1 ppm for o-dichlorobenzene,due to the preconcentration effect of PDMS.Theoretical calculations further explain the combined effect of electromagnetic and chemical enhancement in this composite substrate.By utilizing the developed visual SERS barcode,quick multiple detection and analysis of mixtures can be accomplished.This flexible and versatile SERS technique has significant potential for on-site detection and analysis of environmental pollutants,opening the doors for the development of a wearable in-situ SERS sensing platform.

Interface engineering of MXene-based heterostructures for lithiumsulfur batteries

High energy density and low cost make lithium-sulfur(Li-S)batteries as one of the next generation's promising energy storage systems.However,the following problems need to be solved before commercialization:(i)the shuttling effect and sluggish redox kinetics of lithium polysulfides in sulfur cathode;(ii)the formation of lithium dendrites and the crack of solid electrolyte interphase;(iii)the large volume changes during charge and discharge processes.MXenes,as newly emerging two-dimensional transition metal carbides/nitrides/carbonitrides,have attracted widespread attention due to their abundant active surface terminals,adjustable vacancies,and high electrical conductivity.Designing MXene-based heterogeneous structures is expected to solve the stacking problem induced by hydrogen bonds or Van der Waals force and to provide other charming physiochemical properties.Herein,we generalize the design principles of MXene-based heterostructures and their functions,i.e.,adsorption and catalysis in advanced conversion-based Li-S batteries.Firstly,the physiochemical properties of MXene and MXene-based heterostructures are briefly introduced.Secondly,the catalytic functions of MXene-based heterostructures with the compositional constituents including carbon materials,metal compounds,organic frameworks,polymers,single atoms and special high-entropy MXenes are comprehensively summarized in sulfur cathodes and lithium anodes.Finally,the challenges of MXene-based heterostructure in current Li-S batteries are pointed out and we also provide some enlightenments for future developments in high-energy-density Li-S batteries.

Construction of novel cluster-based MOF as multifunctional platform for CO_(2) catalytic transformation and dye selective adsorption

Synthetic conditions and ligands are the key structural defining factors of metal-organic frameworks(MOFs).Therefore,reasonable optimization of these aspects is considered to be an effective means for designing materials with novel structures and target functions.Herein,two novel Co(Ⅱ)-based MOFs,namely[Co(HL)(dibp)]_(n)(HL-8) and{[Co_(2)(L)(OH)(dibp)]·DMA}_n(HL-9)(H_(3)L=2',6'-dimethyl-[1,1'-biphenyl]-3,4',5-tricarboxylic acid;dibp=4,4'-di(1H-imidazol-1-yl)-1,1-biphenyl]),have been hydrothermally synthesized and structurally characterized.HL-8 crystallizes in the orthorhombic system (Pna2_(1)) with a grid layer structure,while HL-9 crystallizes in the monoclinic P2_(1)/n space group assembled through Co_(4)(OH)_(2)clusters with organic ligands.Remarkably,benefiting from the finite cage-like structure,HL-9 exhibited enhanced performance in carbon dioxide(CO_(2)) adsorption/catalytic transformation and excellent size selectivity during dye molecular adsorption process.

Finite-dimensional simple modular Lie superalgebra M

A new family of finite-dimensional simple modular Lie superalgebra M is constructed based on results of Y. Z. Zhang and Q. C. Zhang [J. Algebra, 2009, 321： 3601-3619]. The simplicity and generators of M are discussed and the derivation superalgebra of M is characterized. Furthermore, the invariance of the nonnatural filtration of M is determined by the method of minimal dimension of image spaces.

A perspective on high-entropy two-dimensional materials

In past decades,high-entropy(HE)materials,containing five or more elements with approximately equal atomic ratio,are extensively investigated due to their desirable properties in a series of applications.Recently,HE two-dimensional(2D)materials have become promising materials,which not only endow the advantages from their bulk form but also exhibit unusual properties due to their 2D features.So far,the HE 2D transition metal carbides(MXenes),dichalcogenides(TMDs),hydrotalcites(LDHs),and oxides have been successfully synthesized and performed well in different electrochemical reactions,which is originated from the synergistic effect of multicomponents and atomic thin characteristics.Here,the challenges on processing,characterization,and property predictions of HE 2D materials are emphasized.Finally,viable strategies,advanced processing,fundamental understanding,in-depth characterization of new HE 2D materials are proposed.

One-step synthesis of recoverable CuCo2S4 anode material for high-performance Li-ion batteries

A facile one-step hydrothermal method has been adopted to directly synthesize the CuCo2S4 material on the surface of Ni foam.Due to the relatively large specific surface area and wide pore size distribution,the CuCo2S4 material not only effectively increases the reactive area,but also accommodates more side reaction products to avoid the difficulty of mass transfer.When evaluated as anode for Li-ion batteries,the CuCo2S4 material exhibits excellent electrochemical performance including high discharge capacity,outstanding cyclic stability and good rate performance.At the current density of 200 mA·g^-1,the CuCo2S4 material shows an extremely high initial discharge capacity of 2510 mAh·g^-1,and the cycle numbers of the material even reach 83 times when the discharge capacity is reduced to 500 mAh·g^-1.Furthermore,the discharge capacity can reach 269 mAh·g^-1 at a current of 2000 mA·g^-1.More importantly,when the current density comes back to 200 mA·g^-1,the discharge capacity could be recovered to 1436 mAh·g^-1,suggesting an excellent capacity recovery characteristics.

Two isostructural Ni(Ⅱ)/Co(Ⅱ)-based metal-organic frameworks for selective dye adsorption and catalytic cycloaddition of CO_(2) with epoxides

Two isostructu ral Ni(Ⅱ)/Co(Ⅱ)-based metal-organic frameworks(MOFs),namely {[M_(3)(L)_(2)(bpb)_(3)(H_(2) O)_(4)]·2 DMF·2 H_(2)O}_(n) [M=Ni(HL-5,HL is short for Hui-Ling Liu);M=Co(HL-6);H_(3) L=2',6'-dimethyl-[1,1'-biphenyl]-3,4',5-tricarboxylic acid;bpb=1,4-bis(pyrid-4-yl)benzene],have been hydrothermally synthesized and structu rally characterized.Both HL-5 and HL-6,which have the same three-interpenetrated3 D pillared-layer framework with sqc306 type topology,present good selective methyl orange(MO)adsorption over rhodamine B(RhB).Moreover,the catalytic CO_(2) cycloaddition properties with epoxides of the two MOFs have also been studied at ambient pressure and temperature.

A class of generalized odd HamUtonian Lie superalgebras

We study class of finite-dimensional Cantan-type Lie superalgebras HO（m） over a field of prime characteristic, which can be regarded as extensions of odd Hamiltonian superalgebra HO. And we also determine the derivation superalgebras of Lie superalgebras HO（m）.

Electron delocalization-enhanced sulfur reduction kinetics on an MXene-derived heterostructured electrocatalyst

Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free Li^(+)and improving the Li^(+)diffusion kinetics will effectively enhance the cell performance.Here,Mo-based MXene heterostructure(MoS_(2)@Mo_(2)C)was developed by partial vulcanization of Mo_(2)C MXene,in which the introduction of similar valence S into Mo-based MXene(Mo_(2)C)can create an electron delocalization effect.Through theoretical simulations and electrochemical characterisation,it is demonstrated that the MoS_(2)@Mo_(2)C heterojunction can effectively promote ion desolvation,increase the amount of free Li^(+),and accelerate Li^(+)transport for more efficient polysulfide conversion.In addition,the MoS_(2)@Mo_(2)C material is also capable of accelerating the oxidation and reduction of polysulfides through its sufficient defects and vacancies to further enhance the catalytic efficiency.Consequently,the Li-S battery with the designed MoS_(2)@Mo_(2)C electrocatalyst performed for 500 cycles at 1 C and still maintained the ideal capacity(664.7 mAh·g^(−1)),and excellent rate performance(567.6 mAh·g^(−1)at 5 C).Under the extreme conditions of high loading,the cell maintained an excellent capacity of 775.6 mAh·g^(−1)after 100 cycles.It also retained 838.4 mAh·g^(−1)for 70 cycles at a low temperature of 0℃,and demonstrated a low decay rate(0.063%).These results indicate that the delocalized electrons effectively accelerate the catalytic conversion of lithium polysulfide,which is more practical for enhancing the behaviour of Li-S batteries.