Laser-Derived Interfacial Confinement Enables Planar Growth of 2D SnS_(2) on Graphene for High-Flux Electron/Ion Bridging in Sodium Storage

Establishing covalent heterointerfaces with face-to-face contact is promising for advanced energy storage,while challenge remains on how to inhibit the anisotropic growth of nucleated crystals on the matrix.Herein,faceto-face covalent bridging in-between the 2 D-nanosheets/graphene heterostructure is constructed by intentionally prebonding of laser-manufactured amorphous and metastable nanoparticles on graphene,where the amorphous nanoparticles were designed via the competitive oxidation of Sn-O and Sn-S bonds,and metastable feature was employed to facilitate the formation of the C-S-Sn covalent bonding in-between the heterostructure.The face-to-face bridging of ultrathin SnS;nanosheets on graphene enables the heterostructure huge covalent coupling area and high loading and thus renders unimpeded electron/ion transfer pathways and indestructible electrode structure,and impressive reversible capacity and rate capability for sodium-ion batteries,which rank among the top in records of the SnS_(2)-based anodes.Present work thus provides an alternative of constructing heterostructures with planar interfaces for electrochemical energy storage and even beyond.

Rational Design of High-Performance PEO/Ceramic Composite Solid Electrolytes for Lithium Metal Batteries

Composite solid electrolytes(CSEs)with poly(ethylene oxide)(PEO)have become fairly prevalent for fabricating high-performance solid-state lithium metal batteries due to their high Li~+solvating capability,flexible processability and low cost.However,unsatisfactory room-temperature ionic conductivity,weak interfacial compatibility and uncontrollable Li dendrite growth seriously hinder their progress.Enormous efforts have been devoted to combining PEO with ceramics either as fillers or major matrix with the rational design of two-phase architecture,spatial distribution and content,which is anticipated to hold the key to increasing ionic conductivity and resolving interfacial compatibility within CSEs and between CSEs/electrodes.Unfortunately,a comprehensive review exclusively discussing the design,preparation and application of PEO/ceramic-based CSEs is largely lacking,in spite of tremendous reviews dealing with a broad spectrum of polymers and ceramics.Consequently,this review targets recent advances in PEO/ceramicbased CSEs,starting with a brief introduction,followed by their ionic conduction mechanism,preparation methods,and then an emphasis on resolving ionic conductivity and interfacial compatibility.Afterward,their applications in solid-state lithium metal batteries with transition metal oxides and sulfur cathodes are summarized.Finally,a summary and outlook on existing challenges and future research directions are proposed.

Hybrid hard carbon framework derived from polystyrene bearing distinct molecular crosslinking for enhanced sodium storage

Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores.Here,a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800℃ via in situ fusion and embedding strategy.This is realized by integrating triazine-and carbonylcrosslinked polystyrene nanospheres during carbonization.The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores,which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking.Therefore,the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior,showing an ICE of 70.2%,a high capacity of 279.3 mAh g^(-1),and long-term 500 cycles,superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature.The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodiumion batteries.

TiO_(2)Electron Transport Layer with p-n Homojunctions for Efficient and Stable Perovskite Solar Cells

Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.

Porous nitrogen-enriched hollow carbon nanofibers as freestanding electrode for enhanced lithium storage

Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.

Architecture engineering of carbonaceous anodes for high-rate potassium-ion batteries

The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium-ion battery.Potassium-ion batteries(KIBs)are regarded as a kind of promising candidate for large-scale energy storage owing to the high abundance and low cost of potassium resources.Nevertheless,further development and wide application of KIBs are still challenged by several obstacles,one of which is their fast capacity deterioration at high rates.A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies.This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high-rate performances for KIBs,and also the beneficial conceptions are consciously extracted from the recent progress.Particularly,basic insights into the recent engineering strategies,structural innovation,and the related advances of carbonaceous anodes for high-rate KIBs are under specific concerns.Based on the achievements attained so far,a perspective on the foregoing,and proposed possible directions,and avenues for designing high-rate anodes,are presented finally.

Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated.The sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite growth.As a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are achieved.This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.

Full-chain enhanced ion transport toward stable lithium metal anodes

The dendrite growth that results from the slow electrode process kinetics prevents the lithium(Li) metal anode from being used in practical applications. Here, full-chain enhanced ion transport for stabilizing Li metal anodes is proposed. Experimental and theoretical studies confirm that full-chain enhanced ion transport(electrocrystallization, mass transport in the electrolyte and diffusion in solid electrolyte interphase) under magnetoelectrochemistry contributes to a homogeneous, dense, and dendrite-free morphology. Specifically, the enhanced electrocrystallization behavior promotes the Li nucleation;the enhanced mass transport in the electrolyte alleviates the ion concentration gradient at the electrode surface, which helps to inhibit dendrite growth;and the enhanced diffusion in the solid electrolyte interphase further homogenizes the Li deposition behavior, obtaining regular and uniform Li particles.Consequently, the Li metal anode has exceptional cycling stability in both symmetric and full cells,and the pouch cell performs long cycles(170 cycles) in practice evaluation. This work advances fundamental knowledge of the magneto-dendrite effect and offers a new perspective on stabilizing metal anodes.

Cross-linked polyelectrolyte reinforced SnO_(2)electron transport layer for robust flexible perovskite solar cells

SnO_(2)electron transport layer(ETL)is a vital component in perovskite solar cells(PSCs),due to its excellent photoelectric properties and facile fabrication process.In this study,we synthesized a water-soluble and adhesive polyelectrolyte with ethanolamine(EA)and poly-acrylic acid(PAA).The linear PAA was crosslinked by EA,forming a 3D network that stabilized the SnO_(2)nanoparticle dispersion.An organic–inorganic hybrid ETL is developed by introducing the cross-linked PAA-EA into SnO_(2)ETL,which prevents nano particle agglomeration and facilitates uniform SnO_(2)film formation with fewer defects.Additionally,the PAA-EA-modified SnO_(2)facilitated a uniform and compact perovskite film,enhancing the interface contact and carrier transport.Consequently,the PAA-EA-modified PSCs exhibited excellent PCE of 24.34%and 22.88%with high reproducibility for areas of 0.045 and 1.00 cm~2,respectively.Notably,owing to structure reinforce effect of PAA-EA in SnO_(2)ETL,flexible device demonstrated an impressive PCE of 23.34%while maintaining 90.1%of the initial PCE after 10,000 bending cycles with a bending radius of 5 mm.This successful approach of polyelectrolyte reinforced hybrid organic–inorganic ETL displays great potential for flexible,large-area PSCs application.

Affinity-Engineered Flexible Scaffold toward Energy-Dense, Highly Reversible Na Metal Batteries

The practical deployment of metallic anodes in the energy-dense batteries is impeded by the thermodynamically unstable interphase in contact with the aprotic electrolyte,structural collapse of the substrates as well as their insufficient affinity toward the metallic deposits.Herein,the mechanical flexible,lightweight(1.2 mg cm^(−2))carbon nanofiber scaffold with the monodispersed,ultrafine Sn_(4)P_(3) nanoparticles encapsulation(Sn_(4)P_(3)NPs@CNF)is proposed as the deposition substrate toward the high-areal-capacity sodium loadings up to 4 mAh cm^(−2).First-principles calculations manifest that the alloy intermediates,namely the Na_(15)Sn_(4) and Na_(3)P matrix,exhibit the intimate Na affinity as the“sodiophilic”sites.Meanwhile,the porous CNF regulates the heterogeneous alloying process and confines the deposit propagation along the nanofiber orientation.With the precise control of pairing mode with the NaVPO4F cathode(8.7 mg cm^(−2)),the practical feasibility of the Sn_(4)P_(3) NPs@CNF anode(1^(*)Na excess)is demonstrated in 2 mAh single-layer pouch cell prototype,which achieves the 95.7%capacity retention for 150 cycles at various mechanical flexing states as well as balanced energy/power densities.

Multifunctional interfacial and structural anode for dendrite-free lithium metal-based batteries

Lithium(Li)metal is considered as the candidate for the next generation of Li metal battery(LMB)anodes due to its high capacity and the lowest potential,which is expected to meet the requirements of energy storage devices.Unfortunately,the uncontrollable growth of Li dendrites during the charge/discharge process,as well as the resulting problems of poor cycling stability,low coulomb efficiency and safety risk,has restricted the commercialization of Li anode.Herein,an in-situ interfacial film containing three-dimensional(3D)rod-like micron-structure silver(Ag)is constructed on the surface of the Li metal.Due to the 3D rod-like micron-structure used to homogenize the distribution of current density,achieving uniform nucleation and growth of electrodeposited Li,the produced Li-Ag alloy was employed to restrain the formation of“dead”Li and the in-situ formed LiNO_(3) was utilized to facilitate the stability of solid-electrolyte interface(SEI)film,so the growth of dendritic Li is suppressed via the synergistic effect of structure and surface chemistry regulation.The obtained Li anode can achieve cycling stability at a high current density of 10 mA/cm^(2).This work considers multiaspect factors inducing uniform Li electrodeposition,and provides new insights for the commercialization of LMB.

A self-healing liquid metal anode for lithium-ion batteries

The gallium-based liquid metal as one of the self-healing materials has gained wide attention, especially in the energy storage system. However, volume expansion with the ‘‘liquid-solid-liquid”transformation process still leads to un-controlled electrode failure, which stimulates the irreversibility of liquid metal and hinders their self-healing effect as the anode for lithium-ion batteries. Herein, the polypyrrole(PPy) with highly conductive and adhesive features is first introduced to fasten the liquid metal nanoparticles(gallium-tin alloy, EGaSn) in the integrated electrode and applied as the anode for lithium-ion batteries. A tightly PPy wrapped EGaSn nanoparticles structure is formed during the in-situ polymerization synthesis process, which effectively avoids the detachment of solid alloyed products. Based on the features of PPy, polyacrylic acid is added to facilitate strengthening the integrity of the electrode by constructing the hydrogen bond. The ‘‘dual-insurance” design endows the EGaSn to exhibit superior electrochemical kinetics and an astonishing self-healing effect. As a result, the customized anode displays superior cycling stability(499.8 mAh g^(-1) after 500 cycles at 1.0 A g^(-1))and rate capability(350 mAh g^(-1) at 2.0 A g^(-1)).This work enriches the electrode engineering technology of liquid metal nanoparticles and opens up a new way to customize the self-healing anode for lithium-ion batteries.

A multifunctional electrolyte with highly-coordinated solvation structure-in-nonsolvent for rechargeable lithium batteries

Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery systems.However, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of high-voltage intercalation-type cathodes largely prevent their practical deployment.Herein, to fully conquer the three challenges via one strategy, a novel electrolyte with highlycoordinated solvation structure-in-nonsolvent is designed. On account of the particular electrolyte structure, the shuttle effect is completely suppressed by quasi-solid conversion of S species in Li-S batteries,with a stable cycle performance even at lean electrolyte(5μL mg^(-1)). Simultaneously, in-situ-formed highly-fluorinated interphases can not only lower Li+diffusion barrier to ensure uniform nucleation of Li but also improve stability of NCM cathodes, which enable excellent capacity retention of Lik LiNi(0.5)Co(0.2)Mn(0.3)O2 batteries under conditions toward practical applications(high loading of 2.7 m Ah cm^(-2) and lean electrolyte of 5 m L Ah^(-1)). Besides, the electrolyte is also nonflammable. This electrolyte structure offers useful guidelines for the design of novel organic electrolytes for practical lithium-based batteries.

Growing curly graphene layer boosts hard carbon with superior sodium-ion storage

Benefiting from the distinctive ordering degree and local microstructure characteristics,hard carbon(HC)is considered as the most promising anode for sodium-ion batteries(SIBs).Unfortunately,the low initial Coulombic efficiency(ICE)and limited reversible capacity severely impede its extensive application.Here,a homogeneous curly graphene(CG)layer with a micropore structure on HC is designed and executed by a simple chemical vapor deposition method(without catalysts).CG not only improves the electronic/ionic conductivity of the hard carbon but also effectively shields its surface defects,enhancing its ICE.In particular,due to the spontaneous curling structural characteristics of CG sheets(CGs),the micropores(≤2 nm)formed provide additional active sites,increasing its capacity.When used as a sodium-ion battery anode,the HC-CG composite anode displayed an outstanding reversible capacity of 358 mAh·g^(-1),superior ICE of 88.6%,remarkable rate performance of 145.8 mAh·g^(-1)at 5 A·g^(-1),and long cycling life after 1000 cycles with 88.6%at 1 A·g^(-1).This work provides a simple defect/microstructure turning strategy for hard carbon anodes and deepens the understanding of Na+storage behavior in the plateau region,especially on the pore-filling mechanism by forming quasi-metallic clusters.

Kinetically regulated one-pot synthesis of cationic gold nanoparticles and their size-dependent antibacterial mechanism

Cationic gold nanoparticles(cAuNPs)have been regarded as promising candidates for antibacterial applications due to their high surface charge density,favorable biocompatibility,and controllable surface chemistry.Nevertheless,the complicated fabrication process and unclear antibacterial mechanism have greatly hindered the further biomedical application of cAuNPs.Herein,we have developed a simple and controllable strategy for synthesizing cAuNPs with tailored size and antibacterial behavior by kinetically modulating the reaction process.Specifically,a functional ligand,(11-mercaptoundecyl)-N,N,Ntrimethylammonium bromide(MUTAB),was chosen to chemically manipulate the positive surface charge of cAuNPs via a one-step strategy.The size of cAuNPs could be flexibly adjusted from 1.1 to 14.8 nm by simply elevating the stirring speed of the reaction from 0 to 1500 rpm.Further studies revealed that the antibacterial effect of cAuNPs was strongly correlated with the particle size.MUTAB-protected ultrasmall gold nanoclusters(MUTAB-AuNCs)were able to eradicate E.coli at a concentration as low as 1.25μg mL^(-1),while the minimum inhibitory concentration of MUTAB-AuNPs with a large size for E.coli was 5μg mL^(-1).Mechanistic investigation revealed that MUTAB-AuNPs were able to damage the bacterial membrane and stimulate the production of reactive oxygen species more effectively than MUTAB-AuNCs.Conversely,MUTAB-AuNCs were more active in inducing membrane depolarization in contrast to MUTAB-AuNPs,suggesting the unique size-dependent antibacterial manner of cAuNPs.This study presents a new strategy for the controlled preparation of cAuNPs with distinct sizes and antibacterial behavior,laying a valuable foundation for developing efficient cationic NP-based bactericidal agents.

Ratiometric fluorescence and visual sensing of ATP based on gold nanocluster-encapsulated metal-organic framework with a smartphone

Adenosine triphosphate(ATP)plays an important role in various biological processes and the ATP level is closely associated with many diseases.Herein,we designed a novel dual-emissive fluorescence nanoplatform for ATP sensing based on red emissive europium metal-organic framework(Eu-MOF)and blue emissive gold nanoclusters(AuNCs).The presence of ATP causes the decomposition of Eu-MOF owing to strong affinity of Eu3+with ATP.As a result,the red emission of Eu-MOF decreases while the blue emission of AuNCs remains unchanged.The distinct red/blue emission intensity change enables the establishment of a ratiometric fluorescent and visual sensor of ATP.Moreover,a fluorescent paper-based sensor was fabricated with the ratiometric ATP probes,which enabled easy-to-use and visual detection of ATP in serum samples with a smartphone.

Regulating electrodeposition behavior through enhanced mass transfer for stable lithium metal anodes

Electrode process kinetics is a key part that determines the morphology of metal electrodeposition.However,the liquid-phase mass transfer process and its effect on lithium(Li)metal electrodeposition are still poorly understood.Herein,the effect of mass transfer on the electrodeposition behavior of Li metal is explored.Experiments and COMSOL Multiphysics simulations reveal that the enhanced mass transfer,which is induced by ultrasonic wave,can homogenize the ion flow on the surface of electrode to obtain uniform Li nucleation.Meanwhile,the rapid mass transfer of Li^(+)provides sufficient cations around the germinated Li to avoid preferential growth of Li in a specific direction.Based on the simultaneous regulation of nucleation and growth behavior,a smooth and compact Li deposits can be achieved,which exhibit a small polarization voltage during repeated Li plating/striping and a considerably enhanced cyclability.This work enriches the fundamental understanding of Li electrodeposition without dendrite structure and affords fresh guidance to develop dendrite-free metal anodes for metal-based batteries.

Understanding and quantifying capacity loss in storage aging of Ah-level Li metal pouch cells

Promoting industry applications of high-energy Li metal batteries(LMBs)is of vital importance for accelerating the electrification and decarbonization of our society.Unfortunately,the time-dependent storage aging of Ah-level Li metal pouch cells,a ubiquitous but crucial practical indicator,has not yet been revealed.Herein,we first report the storage behaviors and multilateral synergistic aging mechanism of Ah-level NCM811jjLi pouch cells during the 120-day long-term storage under various conditions.Contrary to the conventional belief of Li-ion batteries with graphite intercalation anodes,the significant available capacity loss of 32.8%on average originates from the major electrolyte-sensitive anode corrosion and partial superimposed cathode degradation,and the irreversible capacity loss of 13.3%is essentially attributed to the unrecoverable interface/structure deterioration of NCM with further hindrance of the aged Li.Moreover,principles of alleviating aging have been proposed.This work bridges academia and industry and enriches the fundamental epistemology of storage aging of LMBs,shedding light on realistic applications of high-energy batteries.

Site-specific fabrication of gold nanocluster-based fluorescence photoswitch enabled by the dual roles of albumin proteins

Fluorescence photoswitch is becoming increasingly desirable for many applications,but its controllable fabrication still remains challenging yet.In this paper,a new strategy is proposed to fabricate fluorescence photoswitch by harnessing dual roles of albumin proteins as both photochrome carriers and biotemplates of fluorophore.As an example,we demonstrated the successful fabrication of a fluorescence photoswitch by incorporating both the photochromic diarylethene dye(CMTE)and red-emitting fluorescent gold nanoclusters(AuNCs)into the specific domains of bovine serum albumin(BSA)in a highly controllable manner.Detailed spectral and photophysical characterisation showed that CMTE well-retains the photochromic properties within the CMTE–BSA–AuNC construct,although its photoconversion rate is slightly retarded.Different from previously reported photoswitches,the fluorescence of the present system is mainly modulated via the inner filter effect(IFE)mechanism,which exhibits high switching efficiency with an on-off ratio up to 90%,reversible fluorescence response and good antifatigue performance.This work provides a new,generable albumin protein-assisted strategy of fabricating advanced fluorescence photoswitch,which can find wide applications in biological,optical and information fields.

Emerging applications of near-infrared fluorescent metal nanoclusters for biological imaging

Fluorescent metal nanoclusters（MNCs） have recently emerged as a novel kind of promising fluorescent probes for biological imaging because of their ultrasmall core size（〈2 nm）, strong photoluminescence,facile availability and good biocompatibility. In this review, we provide an update on recent advances in the development of near infrared（NIR）-emitting MNCs in terms of synthesis strategies and bioimaging applications. We mainly focus on the utilization of NIR-emitting MNCs（including Au, Ag, Cu and alloy NCs） either as single modal imaging（fluorescence intensity-based imaging, fluorescence lifetime imaging, two-photon imaging） probes or as multimodal imaging（such as NIR fluorescence/X-ray computed tomography/magnetic resonance imaging, NIR fluorescence/photoacoustic imaging/magnetic resonance imaging, NIR fluorescence/single photon emission computed tomography） probes in biological cells and tissues. Finally, we give a brief outlook on the future challenges and prospects of developing NIR-emitting MNCs for bioimaging.