Two-dimensional(2D)materials offer countless possibilities for next-generation(opto)electronic devices because of their diverse and tailorable physicochemical characteristics.To bridge the gap between fundamental science and practical applications,simple-to-use universal approaches are essential for the mass production of 2D materials with specific target properties.Electrochemical intercalation/exfoliation stands out from many up-scalable synthetic strategies,thanks to its great time efficiency,mild working conditions,and simple instrumentation.Besides the use for direct exfoliation of 2D materials,device-level controllable intercalation of guest species often results in rich phase diagrams with competing orders and ground states in 2D systems,giving rise to new exotic quantum phenomena.Therefore,making use of electrochemistry in ion intercalation and host–guest interaction is crucial to expand the library,as well as the function of 2D materials.Here,we present a focused review of the exciting advances of electrochemical exfoliation and engineering of 2D materials,including intercalation strategies,intercalation chemistry,exfoliation mechanisms,material properties,and potential applications.An outlook on the major challenges and perspectives is also presented at the end of the discussion.
The electrochemical properties of 2D materials,particularly transition metal dichalcogenides(TMDs),hinge ontheir structural and chemical characteristics.To be practicallyviable,achieving large-scale,high-yield production is crucial,ensuring both quality and electrochemical suitability forapplications in energy storage,electrocatalysis,and potentialbasedionic sieving membranes.A prerequisite for success is a deepunderstanding of the synthesis process,forming a critical linkbetween materials synthesis and electrochemical performance.Thisreview extensively examines the liquid-phase exfoliation technique,providing insights into potential advancements and strategies tooptimize the TMDs nanosheet yield while preserving theirelectrochemical attributes.The primary goal is to compiletechniques for enhancing TMDs nanosheet yield through direct liquid-phase exfoliation,considering parameters like solvents,surfactants,centrifugation,and sonication dynamics.Beyond addressing the exfoliation yield,the review emphasizes the potentialimpact of these parameters on the structural and chemical properties of TMD nanosheets,highlighting their pivotal role inelectrochemical applications.Acknowledging evolving research methodologies,the review explores integrating machine learning anddata science as tools for understanding relationships and key characteristics.Envisioned to advance 2D material research,includingthe optimization of graphene,MXenes,and TMDs synthesis for electrochemical applications,this compilation charts a coursetoward data-driven techniques.By bridging experimental and machine learning approaches,it promises to reshape the landscape ofknowledge in electrochemistry,offering a transformative resource for the academic community.
The weak van der Waals gap endows two dimensional transition metal dichalcogenides(2D TMDs)with the potential to realize guest intercalation and host exfoliation.Intriguingly,the liquid intercalation and exfoliation is a facile,low-cost,versatile and scalable strategy to modulate the structure and physiochemical property of TMDs via introducing foreign species into interlayer.In this review,firstly,we briefly introduce the resultant hybrid superlattice and disperse nanosheets with tailored properties fabricated via liquid intercalation and exfoliation.Subsequently,we systematically analyze the intercalation phenomenon and limitations of various intercalants in chemical or electrochemical methods.Afterwards,we intensely discuss diverse functionalities of resultant materials,focusing on their potential applications in energy conversion,energy storage,water purification,electronics,thermoelectrics and superconductor.Finally,we highlight the challenges and outlooks for precise and mass production of 2D TMDs-based materials via liquid intercalation and exfoliation.This review enriches the overview of liquid intercalation and exfoliation strategy,and paves the path for relevant high-performance devices.
Yan TuLingbin XieMengyang ZhangShujuan LiuZhongzhong LuoLonglu WangQiang Zhao
The impact of cooling rate after solution heat treatment on exfoliation corrosion resistance of a Li-containing 7xxx aluminum alloy was investigated by accelerated immersion and electrochemical impedance spectroscopy test,optical microscope,electron backscatter diffraction and scanning transmission electron microscope.With the decrease of cooling rate from 1700℃/s to 4℃/s,exfoliation corrosion resistance of the aged specimens decreases with rating changing from EA to EC and the maximum corrosion depth increasing from about 169.4μm to 632.1μm.Exfoliation corrosion tends to develop along grain boundaries in the specimens with cooling rates higher than about 31℃/s and along both grain boundaries and sub-grain boundaries in the specimens with lower cooling rates.The reason has been discussed based on the changes of the microstructure and microchemistry at grain boundaries and sub-grain boundaries due to slow cooling.
The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive operation.The introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it.Consequently,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/g.Furthermore,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g.This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.
Qian LiHu ZhengBinbin LiuTianzhen JianWenqing MaCaixia XuKai Wang
As one promising carbon-based material,sp^(3)-hybrid carbon nitride has been predicted with various novel physicochemical properties.However,the synthesis of sp^(3)-hybrid carbon nitride is still limited by the nanaoscale,low crystallinity,complex source,and expensive instruments.Herein,we have presented a facile approach to the sp^(3)-hybrid carbon nitride nano/micro-crystals with microwave-assisted confining growth and liquid exfoliation.Actually,the carbon nitride nano/micro-crystals can spontaneously emerge and grow in the microwave-assisted polymerization of citric acid and urea,and the liquid exfoliation can break the bulk disorder polymer to retrieve the highly crystalline carbon nitride nano/micro-crystals.The obtained carbon nitride nano/micro-crystals present superior blue light absorption strength and surprising photoluminescence quantum yields of 57.96% in ethanol and 18.05%in solid state.The experimental characterizations and density functional theory calculations reveal that the interface-trapped localized exciton may contribute to the excellent intrinsic light emission capability of carbon nitride nano/micro-crystals and the interparticle staggered stacking will prevent the aggregation-caused-quenching partially.Finally,the carbon nitride nano/micro-crystals are demonstrated to be potentially useful as the phosphor medium in light-emitting-diode for interrupting blue light-induced eye damage.This work paves new light on the synthesis strategy of sp^(3)-hybrid carbon nitride materials and thus may push forward the development of multiple carbon nitride research.
The exfoliation of bulk 2H-molybdenum disulfide(2H-MoS_(2))into few-layer nanosheets with 1T-phase and controlled layers represents a daunting challenge towards the device applications of MoS_(2).Conventional ion intercalation assisted exfoliation needs the use of hazardous n-butyllithium and/or elaborate control of the intercalation potential to avoid the decomposition of the MoS_(2).This work reports a facile strategy by intercalating Li ions electrochemically with ether-based electrolyte into the van der Waals(vdW)channels of MoS_(2),which successfully avoids the decomposition of MoS_(2)at low potentials.The co-intercalation of Li+and the ether solvent into MoS_(2)makes a first-order phase transformation,forming a superlattice phase,which preserves the layered structure and hence enables the exfoliation of bulk 2H-MoS_(2)into bilayer nanosheets with 1T-phase.Compared with the pristine 2H-MoS_(2),the bilayer 1T-MoS_(2)nanosheets exhibit better electrocatalytic performance for the hydrogen evolution reaction(HER).This facile method should be easily extended to the exfoliation of various transition metal dichalcogenides(TMDs).
Due to the growing resistance of available drugs to bacterial infection and the slow development of antibiotics,there is a continuous need to design and develop new antibacterial agents.The interest to develop transition metal dichalcogenides(TMDs)based antibacterial agents has significantly increased in recent years.This research interest is driven by their interesting properties such as metallic and semiconducting nature of different phases,electronic confinement,large surface to volume ratio,the possibility of surface functionalization,and their potential application as a material in biomedical sciences.Different synthetic strategies have been developed to synthesize monolayered TMDs and their functionalization with different bioactive molecules.Researchers have given a lot of effort to establish the structure-activity correlation between different TMDs and their antibacterial activity.Here,we have reviewed various exfoliation strategies for TMDs,different methods for their functionalization,and the antibacterial activity of different TMDs.
