Recent progress and future prospects of high-entropy materials for battery applications

Due to the energy crisis caused by limited fossil fuel reserves,extensive use of the renewable energy sources such as wind or solar energy is deemed to replace the use of traditional fossil fuels in the future^([1−3]).However,most renewable energy sources face the same problem,which is the intermittency of energy.For example,solar energy cannot be utilized at night.That means the continuous energy demand required for large-scale power grids can’t be satisfied by a single solar panel model.

Recent progress and future prospect of novel multi-ion storage devices

Rechargeable batteries,especially lithium-ion batteries(LIBs),have made rapid development since the 21st century,greatly facilitating people's lives[1−6].Based on considerations of cost and existing problems(such as safety issues due to LIBs stacking strategy and unsatisfactory performance for various applications),researchers have explored alternative technologies to LIBs to meet the needs for wide application scenarios[5].Among them,multi-ion storage devices such as dual-ion batteries(DIBs)and metal-ion hybrid capacitors(MIHCs)are considered promising alternative energy storage devices of LIBs due to their unique multi-ion storage mechanism.In a multi-ion storage device,cations and anions carry charges back and forth between the electrolyte and the electrodes at the same time,unlike the rocking chair mechanism of LIBs[7].Generally,the anodes of DIBs and MIHCs work in a similar mechanism to LIBs,storing charge through redox reactions.The main difference among them is the mechanism of the cathodes during charging and discharging[8].In DIBs,the battery-type cathode stores anions through the Faraday reaction.

Porous heterostructure of graphene/hexagonal boron nitride as an efficient electrocatalyst for hydrogen peroxide generation

Compared with the traditional heteroatom doping,employing heterostructure is a new modulating approach for carbon-based electrocatalysts.Herein,a facile ball milling-assisted route is proposed to synthesize porous carbon materials composed of abundant graphene/hexagonal boron nitride(G/h-BN)heterostructures.Metal Ni powder and nanoscale h-BN sheets are used as a catalytic substrate/hard template and“nucleation seed”for the formation of the heterostructure,respectively.As-prepared G/h-BN heterostructures exhibit enhanced electrocatalytic activity toward H_(2)O_(2) generation with 86%-95%selectivity at the range of 0.45-0.75 V versus reversible hydrogen electrode(RHE)and a positive onset potential of 0.79 versus RHE(defined at a ring current density of 0.3 mA cm^(-2))in the alkaline solution.In a flow cell,G/h-BN heterostructured electrocatalyst has a H_(2)O_(2) production rate of up to 762 mmol g_(catalyst)^(-1) h^(-1) and Faradaic efficiency of over 75%during 12 h testing,superior to the reported carbon-based electrocatalysts.The density functional theory simulation suggests that the B atoms at the interface of the G/h-BN heterostructure are the key active sites.This research provides a new route to activate carbon catalysts toward highly active and selective O_(2)-to-H_(2)O_(2) conversion.

Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

Carbon-and silica-based nanomaterials possess a set of merits including large surface area,good structural stability,diversified morphology,adjustable structure,and biocompatibility.These outstanding features make them widely applied in different fields.However,limited by the surface free energy effect,the current studies mainly focus on the symmetric structures,such as nanospheres,nanoflowers,nanowires,nanosheets,and core-shell structured composites.By comparison,the asymmetric structure with ingenious adjustability not only exhibits a larger effective surface area accompanied with more active sites,but also enables each component to work independently or corporately to harness their own merits,thus showing the unusual performances in some specific applications.The current review mainly focuses on the recent progress of design principles and synthesis methods of asymmetric carbon-and silica-based nanomaterials,and their applications in energy storage,catalysis,and biomedicine.Particularly,we provide some deep insights into their unique advantages in related fields from the perspective of materials’structure-performance relationship.Furthermore,the challenges and development prospects on the synthesis and applications of asymmetric carbon-and silica-based nanomaterials are also presented and highlighted.

Elastic Buffering Layer on CuS Enabling High-Rate and Long-Life Sodium-Ion Storage

The latest view suggests the inactive core,surface pulverization,and poly sulfide shuttling effect of metal sulfides are responsible for their low capacity and poor cycling performance in sodium-ion batteries(SIBs).Whereas overcoming the above problems based on conventional nanoengineering is not efficient enough.In this work,erythrocyte-like CuS microspheres with an elastic buffering layer of ultrathin poly aniline(PANI) were synthesized through one-step selfassembly growth,followed by in situ polymerization of aniline.When CuS@PANI is used as anode electrode in SIBs,it delivers high capacity,ultrahigh rate capability(500 mAh gat 0.1 A g,and 214.5 mAh gat 40 A g),and superior cycling life of over 7500 cycles at 20 A g.A series of in/ex situ characterization techniques were applied to investigate the structural evolution and sodium-ion storage mechanism.The PANI swollen with electrolyte can stabilize solid electrolyte interface layer,benefit the ion transport/charge transfer at the PANI/electrolyte interface,and restrain the size growth of Cu particles in confined space.Moreover,finite element analyses and density functional simulations confirm that the PANI film effectively buffers the volume expansion,suppresses the surface pulverization,and traps the poly sulfide.

Graphene quantum dots assisted photovoltage and efficiency enhancement in CdSe quantum dot sensitized solar cells

CdSe quantum dot sensitized solar cells （QDSCs） modified with graphene quantum dots （GQDs） have been successfully achieved in this work for the first time. Satisfactorily, the optimized photovoltage （Voc） of the modified QDSCs was approximately 0.04 V higher than that of plain CdSe QDSCs, consequently improving the photovoltaic performance of the resulting QDSCs. Served as a novel coating on the CdSe QD sensitized photoanode, GQDs played a vital role in improving Voc due to the suppressed charge recombination which has been confirmed by electron impedance spectroscopy as well as transient photovoltage decay measure- ments. Moreover, different adsorption sequences, concentration and deposition time of GQDs have also been systematically investigated to boost the power conversion efficiency （PCE） of CdSe QDSCs. After the coating of CdSe with GQDs, the resulting champion CdSe QDSCs exhibited an improved PCE of 6.59% under AM 1.5G full one sun illumination.

Coating Multi-walled Carbon Nanotubes with Uniform Silica Shells:Independent of Surface Chemistry

A facile and general method was described to coat six types of multi-walled carbon nanotubes, functionalized by either noncovalent or covalent way, with smooth silica shells. 3-Aminopropyltriethoxysilane（APTES） and pH value play important roles in the coating process and the thickness of silica shell could be controlled by the added amount of silicon alkoxides. After the removal of multi-walled carbon nanotubes by calcination, the silica nanotubes were successfully prepared.

Graphene Quantum Dot‑Mediated Atom‑Layer Semiconductor Electrocatalyst for Hydrogen Evolution

The hydrogen evolution reaction performance of semiconducting 2H-phase molybdenum disulfide(2H-MoS_(2))presents a significant hurdle in realizing its full potential applications.Here,we utilize theoretical calculations to predict possible functionalized graphene quantum dots(GQDs),which can enhance HER activity of bulk MoS_(2).Subsequently,we design a functionalized GQD-induced in-situ bottom-up strategy to fabricate near atom-layer 2H-MoS_(2) nanosheets mediated with GQDs(ALQD)by modulating the concentration of electron withdrawing/donating functional groups.Experimental results reveal that the introduction of a series of functionalized GQDs during the synthesis of ALQD plays a crucial role.Notably,the higher the concentration and strength of electron-withdrawing functional groups on GQDs,the thinner and more active the resulting ALQD are.Remarkably,the synthesized near atom-layer ALQD-SO_(3)demonstrate significantly improved HER performance.Our GQD-induced strategy provides a simple and efficient approach for expanding the catalytic application of MoS_(2).Furthermore,it holds substantial potential for developing nanosheets in other transition-metal dichalcogenide materials.

Micro-nano structural electrode architecture for high power energy storage

The necessity and superiorities of micro-nano structural electrodes toward high power:Electrochemical energy storage(EES)technologies have achieved great success in portable electronics and electric vehicles owing to their environmental friendliness and cost effectiveness.With the promotional concepts such as the Internet of Things and ultra-high efficiency self-powered systems in recent years,there are substantial demand for superior EES systems,including but not limited to high-performance,miniaturization and multifunction[1−4].In a particular EES cell,active materials are carried by electrodes as the basic building blocks of energy storage or release.Material innovation(includes composition,structure,size and morphology)has revealed remarkable energy density,power density and lifespan for associated devices in the lab setting of low mass loading slurry-coating electrodes[5].

Interfacial growth of N,S-codoped mesoporous carbon onto biomass-derived carbon for superior potassium-ion storage

Carbonaceous materials have been recognized as one of the most promising anode materials for potassium-ion batteries(PIBs)due to their abundant raw materials,controllable structure,superior conductivity,and good chemical inertness.However,the large radius of K ions and the low potassium content of intercalation compounds result in the sluggish storage kinetics and low reversible capacity of carbon anodes.In this work,we present a unique heteroatom-doped carbon composite(denoted as NS-MC/SC)through a facile interfacial assembly route and simple heat-treatment process,where NS-MC is well grafted onto the biomass-derived spore carbon(SC).This unique structural design endows it with abundant mesoporous channels,expanded layer spacing,and highly doped N and S.With these merits,the NS-MC/SC anode in PIBs exhibits a high reversible capacity of 350.4 mAh·g^(-1) at 100 mA·g^(-1) after 300 cycles,and an outstanding cycling stability.Besides,in-situ Raman spectra further verify the high reversibility of K ions insertion/extraction.Importantly,theoretical simulations also reveal that the N,S dual-doping is an efficient approach for improving the potassium-ion storage performance of NS-MC/SC.

Yolk-shell Si/C composites with multiple Si nanoparticles encapsulated into double carbon shells as lithium-ion battery anodes

The conceptual design of yolk-shell structured Si/C composites is considered to be an effective way to improve the recyclability and conductivity of Si-based anode materials. Herein, a new type of yolk-shell structured Si/C composite (denoted as TSC-PDA-B) has been intelligently designed by rational engineering and precise control. In the novel structure, the multiple Si nanoparticles with small size are successfully encapsulated into the porous carbon shells with double layers benefiting from the strong etching effect of HF. The TSC-PDA-B product prepared is evaluated as anode materials for lithium-ion batteries (LIBs). The TSC-PDA-B product exhibits an excellent lithium storage performance with a high initial capacity of 2108 mAh g^-1 at a current density of 100 mA g^-1 and superior cycling performance of 1113 mAh g^-1 over 200 cycles. The enhancement of lithium storage performance may be attributed to the construction of hybrid structure including small Si nanoparticles, high surface area, and double carbon shells, which can not only increase electrical conductiv让y and intimate electrical contact with Si nanoparticles, but also provide built-in buffer voids for Si nanoparticles to expand freely without damaging the carbon layer. The present findings can provide some scientific insights into the design and the application of advanced Si-based anode materials in energy storage fields.

Facile synthesis of Er^(3+)/Tm^(3+)co-doped magnetic/luminescent nanosystems for possible bioimaging and therapy applications

Manganese-zinc ferrite is a kind of very important magnetic ferrite material.The properties of wide absorption band,sensitivity to ultraviolet(UV)light and tumor H_(2)O_(2) promise it to be possibly used as a photothermal therapy(PTT),photodynamic therapy(PDT)and chemodynamic therapy(CDT)agent.Based on the unique advantages of rare-earth doped nanoparticles,an Er^(3+),Tm^(3+)co-doped upconversion-mediated nanosystem with manganese-zinc ferrite shell(named as UCNPS@M)was developed through a facile thermal co-decomposition method.The final nanosystems were surface-modified by using dopamine hydrochloride(DA)in order to warrant good biocompatibility(named as UCNPS@M@DA).Under irradiation of near-infrared(NIR)light,UCNPS emit both ultraviolet and visible light.The UV light is mostly abso rbed by manga nese-zinc ferrite shell to produce reactive oxygen species(ROS),which is essential to the potential PDT and CDT effect of nanosystems,and at the same time,Mn_(0.5)Zn_(0.5)Fe2O_(4) can further react with H_(2)O_(2) to promote the efficiency of OH-generation.It is expected that UCNPS@M@DA can act as upconversion luminescence imaging guidance due to the visible emission from UCNPS.In addition,the energy absorbed by the nanosystems can be transferred to heat to realize photothermal effect.Moreover,UCNPS@M@DA was successfully applied as a T_(1)/T_(2)-weighted magnetic resonance imaging(MRI)contrast agent due to the existence of Gd,Mn,and Fe elements.In light of the upconversion luminescence(UCL)imaging from the UCNPS as well as potential PTT,PDT,CDT effect mentioned above,this work provides a possibility to realize cancer multi-model bioimaging guided treatment by using an all-in-one diagnosis and therapy nanosystem through a simple yet powerful strategy.

Pumpkin-like MoP-MoS_(2)@Aspergillus niger spore-derived N-doped carbon heterostructure for enhanced potassium storage

Biomass-derived carbon materials are widely applied in the energy storage and conversion fields due to their rich sources,low price and environmental friendliness.Herein,a unique pumpkin-like MoPMoS_(2)@Aspergillus niger spore-derived N-doped carbon(SNC)composite has been prepared via a simple hydrothermal and subsequent phosphorization process.Interestingly,the resulting MoP-MoS_(2)@SNC well inherits the pristine morphology of spore carbon,similar to the natural pumpkin,with hollow interiors and uneven protrusions on the surface.The special structure allows it to have sufficient space to fully contact the electrolyte and greatly reduces the ion transport distance.The theory calculations further demonstrate that the formed MoP-MoS_(2)heterostructure can enhance the adsorption of K ions and electronic couplings.With these unique advantages,the MoP-MoS_(2)@SNC anode for potassium storage shows a high reversible capability of 286.2 mAh g&(-1) at 100 mA g^(-1) after 100 cycles and superior rate performance.The enhanced electrochemical performance is mainly related to the unique pumpkin-like morphology of SNC and the construction of MoP-MoS_(2)heterostructure,as well as their perfect coupling.This study provides a feasible design idea for developing green,low-cost,and high-performance electrode materials for next-generation energy storage.

Boron Nanosheet-Supported Rh Catalysts for Hydrogen Evolution:A New Territory for the Strong Metal-Support Interaction Effect

High-efficiency electrochemical hydrogen evolution reaction(HER)offers a promising strategy to address energy and environmental crisis.Platinum is the most effective electrocatalyst for the HER.However,challenging scarcity,valuableness,and poor electrochemical stability still hinder its wide application.Here,we designed an outstanding HER electrocatalyst,highly dispersed rhodium(Rh)nanoparticles with an average diameter of only 3 nm supported on boron(B)nanosheets.The HER catalytic activity is even comparable to that of commercial platinum catalysts,with an overpotential of only 66 mV in 0.5 M H_(2)SO_(4) and 101 mV in 1 M KOH to reach the current density of 10 mA cm−2.Meanwhile,the catalyst exhibited impressive electrochemical durability during long-term electrochemical processes in acidic and alkaline media,even the simu-lated seawater environment.Theoretical calculations unraveled that the structure-activity relationship between B(104)crystal plane and Rh(111)crystal plane is beneficial to the release of hydrogen,and surface O plays a vital role in the catalysis process.Our work may gain insights into the development of supported metal catalysts with robust catalytic performance through precise engineering of the strong metal-supported interaction effect.

Interaction of multi-walled carbon nanotubes and zinc ions enhances cytotoxicity of zinc ions

More and more nanomaterials enter the environment along with their production, application and deposal. They may alter the biological effect of pollutants already existing in the real environment by different interactions. Therefore efforts should also be paid to investigate the combined toxicity of nanomaterials and pollutants. Herein, we studied the combined toxicity of oxi- dized multi-walled carbon nanotubes （O-MWCNTs） and zinc ions on ceils. It is found that cytotoxicity of the combined O-MWCNTs and zinc ions elevates significantly, compared with O-MWCNTs or zinc ions alone. This result comes from the assays of cell morphology, cell viability and proliferation, cell membrane integrity, mitochondrial membrane potential and cell apoptosis. Mechanism studies indicate that O-MWCNTs absorb zinc ions and form slight aggregation. These enhance remark- ably the cellular uptake of O-MWCNTs, and thus induce the death of cells by bringing in more zinc ions into cells. Our study indicates that the existence of nanomaterials could change the bioconsequence of other pollutants and emphasizes the im- portance of the combined toxicity research in the presence of nanomaterials.

Stable isotope labeling of nanomaterials for biosafety evaluation and drug development

Quantitative information,such as environmental migration,absorption,biodistribution,biotransformation,and elimination,is fundamental and essential for the nanosafety evaluations of nanomaterials.Due to the complexity of biological and environmental systems,it is challenging to develop quantitative approaches and tools that could characterize intrinsic behaviors of nanomaterials in the organisms.The isotopic tracers are ideal candidates to tune the physical properties of nanomaterials while preserving their chemical properties.In this review article,we summarized the stable isotope labeling methods of nanomaterials for evaluating their environmental and biological effects.The skeleton labeling protocols of carbon nanomaterials and metal/metal oxide nanoparticles were introduced.The advantages and disadvantages of stable isotope labeling were discussed in comparison with other quantitative methods for nanomaterials.The quantitative information of nanomaterials in environmental and biological systems was summarized along with the biosafety data.The benefits for drug development of nanomedicine were analyzed based on the targeting effects,persistent accumulation,and safety.Finally,the challenges and future perspectives of stable isotope labeling in nanoscience and nanotechnology were discussed.

Synthesis of Star Polymeric Ionic Liquids and Use as the Stabilizers for High Internal Phase Emulsions

A series of well-defined core cross-linked star （CCS） polymeric ionic liquids （PILs） were synthesized via a three- step approach. First, the styrenic imidazole-based CCS polymer （S-PVBnIm） was prepared by the RAFT-mediated heterogeneous polymerization in a water/ethanol solution, followed by the quaternization of S-PVBnIm with bromoalkanes and anion exchange. The CCS polymers were characterized by gel permeation chromatography （GPC）, nuclear magnetic resonance （NMR） spectroscopy, Fourier transform infrared spectroscopy （FTIR）, thermal gravimetric analysis （TGA）, and differential scanning calorimetry （DSC）. The obtained CCS polymers were used as the effective emulsifiers for oil-in-water high internal phase emulsions （HIPEs）. Multiple oils with different polarity including n-dodecane, undecanol, toluene and octanol were emulsified using 0.5 wt% S-PVBnIm aqueous solution under the acidic condition to form HIPEs with long-term stabilities. The excellent emulsification properties of CCS PILs were demonstrated by HIPE formation for a variety of oils. The properties of HIPEs in terms of emulsion type and oil droplet size were characterized by the confocal laser scanning microscopy （CLSM）. The intriguing capability of CCS PILs to stabilize HIPEs of various oils holds great potentials for the practical applications.

Controllable assembly of nitrogen-doped mesoporous carbon with different pore structures onto CNTs for excellent lithium storage

Mesoporous carbon nanomaterials have shown a great application potential in energy storage and conversion fields due to their outstanding conductivity,tunable pore structure,and good chemical stability.Nevertheless,how to accurately control the pore structure,especially directly assembling the mesoporous carbon onto different substrates remains a big challenge.Herein,we have successfully assembled two kinds of highly nitrogen-doped mesoporous carbon onto carbon nanotubes(NMC/CNTs)based on a facile cooperative assembly process assisted by triblock PEO_(20)PPO_(70)PEO_(20)(P123)and PEO_(106)PPO_(70)PEO_(106)(F127)copolymers.The experimental results indicate that the P_(123)/F_(127)mass ratio has a profound effect on the pore structure,leading to the formation of NMC/CNTs composites with spherical pore structure(S-NMC/CNTs)and cylindrical pore structure(CNMC/CNTs).In virtue of fast electron/ion transfer kinetics,the as-prepared S-NMC/CNTs anode demonstrates an excellent electrochemical performance for lithium-ion batteries,and it delivers a high reversible capacity of 588.1 mAh∙g^(−1)at the current of 0.1 A∙g^(−1)after 100 cycles,along with a superior cycling stability.Specifically noted,the controlled assembly route developed in our work can also be applied to other support materials with different structures and compositions.

Single-particle detection of cholesterol based on the host-guest recognition induced plasmon resonance energy transfer

Plasmon resonance energy transfer(PRET) occurs between the plasmonic nanoparticles(NPs) and organic dyes forming donor-acceptor pairs, which has great potential in quantitative analytical chemistry because of its excellent sensitivity under dark-field microscopy(DFM). Herein, we introduce supramolecular β-cyclodextrin(β-CD) to design a host-guest recognition plasmonic nano-structure modified gold nanoparticles(GNPs), while GNPs and rhodamine molecule(RB) act as the donor and acceptor, respectively. In the presence of the target cholesterol, due to the stronger binding of cholesterol with β-CD, RB molecules are released, inducing the inhibition of PRET, as well as the increase of the scattering intensity of GNPs.The proposed strategy achieves a linear range from 0.02 μmol/L to 2.0 μmol/L for cholesterol detection,and reaches a limit of detection(LOD) of 6.7 nmol/L. This host-guest recognition strategy can easily integrate receptor-donor pair into one nanoparticle, which simplifies the construction of the PRET platform,and further provides an effective approach for PRET-based analytical applications. Afterwards, the proposed PRET strategy was successfully applied for the detection of cholesterol in serum samples with high sensitivity and specificity. The proposed method provides an effective clinically potential means for the detection of cholesterol and other disease-related biomarkers.

Ti_(3)C_(2)T_(x)MXene wrapped,carbon-coated porous Si sheets for improved lithium storage performance

Si-based materials have shown great potential as lithium-ion batteries(LIBs)anodes due to their natural reserves and high theoretical capacity.However,the large volume changes during cycles and poor conductivity of Si lead to rapid capacity decay and poor cycling stability,ultimately limiting their commercial applications.Herein,we have skillfully utilized the microporous MCM-22 zeolite as the unique silicon source to produce porous Si(pSi)sheets by a simple magnesiothermic reduction,followed by a carbon coating and further Ti_(3)C_(2)T_(x)MXene assembly,obtaining the ternary pSi@NC@TNSs composite.In the design,porous Si sheets provide more active sites and shorten Li-ion transport paths for electrochemical reactions.The N-doped carbon(NC)layer serves as a bonding layer to couple pSi and Ti_(3)C_(2)T_(x).The conductive network formed by 2D Ti_(3)C_(2)T_(x)and medium NC layer effectively enhances the overall charge transport of the electrode material,and helps to stabilize the electrode structure.Therefore,the as-made pSi@NC@TNSs anode delivers an improved lithium storage performance,exhibiting a high reversible capacity of 925 mAh/g at 0.5 A/g after 100 cycles.This present strategy provides an effective way towards high-performance Si-based anodes for LIBs.