Synergetic Contributions from the Components of Flexible 3D Structured C/Ag/ZnO/CC Anode Materials for Lithium-Ion Batteries

Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g^(-1)at a current density of 200 mA g^(-1).It also shows good rate performance with reversible capacity of 517 mAh g^(-1)under a high-current density of 5000 mA g^(-1).In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.

Cobalt-Free BaFe_(0.6)Zr_(0.1)Y_(0.3)O_(3−δ)Oxygen Electrode for Reversible Protonic Ceramic Electrochemical Cells

Reversible protonic ceramic electrochemical cells(R-PCECs)are ideal,high-effi ciency devices that are environmentally friendly and have a modular design.This paper studies BaFe_(0.6)Zr_(0.1)Y_(0.3)O_(3−δ)(BFZY3)as a cobalt-free perovskite oxygen electrode for high-performance R-PCECs where Y ions doping can increase the concentration of oxygen vacancies with a remarkable increase in catalytic performance.The cell with confi guration of Ni-BZCYYb/BZCYYb/BFZY3 demonstrated promising performance in dual modes of fuel cells(FCs)and electrolysis cells(ECs)at 650℃with low polarization resistance of 0.13Ωcm^(2),peak power density of 546.59 mW/cm^(2)in FC mode,and current density of−1.03 A/cm^(2)at 1.3 V in EC mode.The alternative operation between FC and EC modes for up to eight cycles with a total of 80 h suggests that the cell with BFZY3 is exceptionally stable and reversible over the long term.The results indicated that BFZY3 has considerable potential as an air electrode material for R-PCECs,permitting effi cient oxygen reduction and water splitting.

1D/2D TiO_(2)/ZnIn_(2)S_(4) S-scheme heterojunction photocatalyst for efficient hydrogen evolution

TiO_(2)is a promising photocatalyst with limited use in practical applications owing to its wide bandgap,narrow light response range,and rapid recombination of photoexcited carriers.To address these limitations,a novel 1D/2D TiO_(2)/ZnIn_(2)S_(4)heterostructure was designed according to the principles of the S-scheme heterojunction.The TiO_(2)/ZnIn_(2)S_(4)(TZISx)hybrids prepared via a hydrothermal method afforded significant improvement in photocatalytic hydrogen evolution(PHE)in comparison to pristine TiO_(2)and ZnIn_(2)S_(4).In particular,the optimal TZIS2 sample(mass ratio of ZnIn_(2)S_(4)to TiO_(2)was 0.4)exhibited the highest PHE activity(6.03 mmol/h/g),which was approximately 3.7 and 2.0 times higher than those of pristine TiO_(2)and ZnIn_(2)S_(4),respectively.This improvement in the PHE of the TZIS2 sample could be attributed to the formation of an intimate heterojunction interface,high-efficiency separation of charge carriers,abundant reactive sites,and enhanced light absorption capacity.Notably,theoretical and experimental results demonstrated that the S-scheme mechanism of interfacial electron transfer in the TZISx composites facilitated the transfer and separation of photoexcited charge carriers,resulting in more isolated photoexcited electrons for the PHE reaction.

Carbon-Based Flexible and All-Solid-State Micro-supercapacitors Fabricated by Inkjet Printing with Enhanced Performance

By means of inkjet printing technique, flexible and all-solid-state micro-supercapacitors(MSCs) were fabricated with carbon-based hybrid ink composed of graphene oxide(GO,98.0vol.%) ink and commercial pen ink(2.0vol.%). A small amount of commercial pen ink was added to effectively reduce the agglomeration of theGO sheets during solvent evaporation and the following reduction processes in which the presence of graphite carbon nanoparticles served as nano-spacer to separate GO sheets. The printed device fabricated using the hybrid ink,combined with the binder-free microelectrodes and interdigital microelectrode configuration, exhibits nearly 780%enhancement in areal capacitance compared with that of pure GO ink. It also shows excellent flexibility and cycling stability with nearly 100% retention of the areal capacitance after 10,000 cycles. The all-solid-state device can be optionally connected in series or in parallel to meet the voltage and capacity requirements for a given application.This work demonstrates a promising future of the carbonbased hybrid ink for directly large-scale inkjet printing MSCs for disposable energy storage devices.

Fabrication and Thermal Insulating Properties of ITO/PVB Nanocomposites for Energy Saving Glass

Chemical co-precipitation method was used to synthesize tin-doped indium oxide（ITO）nanoparticles,and the subsequent solution co-blend was employed to fabricate ITO/PVB nanocomposites.UV（Ultra-violet）-Vis（Visible）-NIR（Near Infrared） spectra show that the addition of ITO nano particles can significantly enhance the thermal insulating efficiency of ITO/PVB nanocomposites.With increasing ITO content,the thermal insulating efficiency is increased.UV is almost fully absorbed by all ITO/PVB nanocomposites.Vis transmittance-haze spectra reveal that ITO/PVB nanocomposites exhibit higher Vis transmittance over 71.3%and lower haze below 2%when ITO content is in the range of 0.1 wt%-0.7 wt%.The UV-Vis-NIR spectroscopy shows that,under the premise of over 70%transmittance to the visible light,the screening effect of the NIR can be enhanced by 80%with 0.7%ITO/PVB nanocomposite membrane compared with the undoped PVB.The thermal insulating tests indicate that,in comparison with the pure PVB film,nanocomposite films with 0.1 wt%-0.9 wt%ITO can reduce temperature by 3-8 ℃.The results show that this novel nanocomposite can be used for energy-saving glass.

Construction of all-organic low dielectric polyimide hybrids via synergistic effect between covalent organic framework and cross-linking structure

Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.

Quasi-solid-state polymer plastic crystal electrolyte for subzero lithium-ion batteries

Succinonitrile(SN)-based polymer plastic crystal electrolytes(PPCEs)have attracted considerable attention as solid-state electrolytes owing to their high ionic conductivities similar to those of liquid electrolytes,excellent contacts with the electrodes,and good mechanic properties.As a crucial property of a solid-state electrolyte,the ionic conductivity of the PPCE directly depends on the interactions between the constituent parts including the polymer,lithium salt,and SN.A few studies have focused on the effects of polymer–lithium–salt and polymer–SN interactions on the PPCE ionic conductivity.Nevertheless,the impact of the lithium–salt–SN combination on the PPCE ionic conductivity has not been analyzed.In particular,tuning of the lithium-salt–SN interaction to fabricate a subzero PPCE with a high low-temperature ionic conductivity has not been reported.In this study,we design and fabricate five PPCE membranes with different weight ratios of Li N(SO2 CF3)2(Li TFSI)and SN to investigate the effect of the Li TFSI–SN interaction on the PPCE ionic conductivity.The ionic conductivities of the five PPCEs are investigated in the temperature range of–20 to 60°C by electro-chemical impedance spectroscopy.The interaction is analyzed by Fourier-transform infrared spectroscopy,Raman spectroscopy,and differential scanning calorimetry.The Li TFSI–SN interaction significantly influences the melting point of the PPCE,dissociation of the Li TFSI salt,and thus the PPCE ionic conductivity.By tuning the Li TFSI–SN interaction,a subzero workable PPCE membrane having an excellent low-temperature ionic conductivity(6×10-4 S cm–1 at 0°C)is obtained.The electro-chemical performance of the optimal PPCE is evaluated by using a Li Co O2/PPCE/Li4 Ti5 O12 cell,which confirms the application feasibility of the proposed quasisolid-state electrolyte in subzero workable lithium-ion batteries.

Synergistic effect of lithiophilic Zn nanoparticles and N-doping for stable Li metal anodes

Li metal is the most ideal anode material for next-generation high energy lithium-ion batteries.The uncontrollable growth of Li dendrites,however,hinders its practical application.Herein,we propose the adoption of Zn nanoparticles uniformly embedded in N-doped carbon polyhedra homogeneously built on carbon cloth(Zn@NC@CC)to prevent the formation of Li dendrites.Based on theoretical calculation and experimental observation,lithiophilic Zn nanoparticles and N-doping inside of the assynthesized Zn@NC play a synergistic role in enhancing the adsorption capacity with Li,thus resulting in uniform Li deposition and complete suppression of Li dendrites.Moreover,the porous N-doped carbon polyhedras uniformly distributed on carbon cloth effectively relieves the volume change of Li upon repeated Li stripping/plating process,which contributes to preserving the structural integrity of the whole electrode and hence enhancing its long-term cycling stability.Benefiting from these synergistic effects,the Li-Zn@NC@CC electrode delivers a prolonged lifespan of over 1200 h at 1 mA cm^(-2) with an areal capacity of 1 mA h cm^(-2) in symmetric cells and high Coulombic efficiencies of 95.4%under an ultrahigh capacity of 12 mA h cm^(-2).Remarkably,Li-Zn@NC@CC//LiFePO_(4) full cells deliver a high reversible capacity of 110.2 mA h g^(-1) at 1 C over 200 cycles.

New Carbon Nitride C_(3)N_(3) Additive for Improving Cationic Defects of Perovskite Solar Cells

Due to the loss of organic amine cations and lead ions in the structure of the iodine-lead methylamine perovskite solar cell,there are a large number of defects within the film and the recombination loss caused by grain boundaries,which seriously hinder the further improvement of power conversion efficiency and stability.Herein,a novel carbon nitride C_(3)N_(3) incorporated into the perovskite precursor solution is a multifunctional strategy,which not only increases the light absorption strength,grain size,and hydrophobicity of the perovskite film,but also effectively passivates the bulk and interfacial defects of perovskite and verified by the first-principles density functional theory calculations.As a result,the efficiency and stability of perovskite solar cells are improved.The device with 0.075 mg mL^(-1) C_(3)N_(3) additive delivers a champion power conversion efficiency of 19.91%with suppressed hysteresis,which is significantly higher than the 18.16% of the control device.In addition,the open-circuit voltage of the modified device with the maximum addition as high as 1.137 V is 90.96% of the Shockley–Queisser limit(1.25 V).Moreover,the power conversion efficiency of the modified device without encapsulation can maintain nearly 90% of its initial value after being stored at 25℃ and 60% relative humidity for 500 h.This work provides a new idea for developing additives to improve the power conversion efficiency and stability of perovskite solar cells.

Fundamental Basis for Distinctive Sensing of H_(2) in Humid Environment

Accurate sensing of trace amount of hydrogen without interference from environment is highly desirable in timely detection of possible leakage when using hydrogen as a clean energy source.Humidity in air is usually considered as the main challenge to the performance of room temperature hydrogen sensors.

Effectively Inhibit Phase Separation to Improve Efficiency and Stability of All-Inorganic Planar CsPbIBr2 Perovskite Solar Cells

The advancement in a power conversion efficiency(PCE)to reach 25%,the inorganic perovskites are being explored intensively as promising optoelectronic materials due to their excellent photovoltaic performance,i.e.,thermal stability and efficiency.Lately,the inorganic cesium lead halide perovskite is studied to show enhanced light absorption,however,it suffers from the phase separate into I-rich and Br-rich phase which leads to poor film quality due to difference of electronegativity.Herein,we propose a unique solution of controlling the rate of solvent volatilization followed by gel method to inhibit phase separation effectively to obtain the homogenous and pinhole-free CsPbIBr2 films with high crystalline quality.In this study,an inverted planar device based on a light absorber of CsPbIBr2 is prepared to achieve a power conversion efficiency of 8.8%(maintain a stabilized value of 8%in ambient air conditions).Surprisingly,the optimized cell without encapsulation shows excellent long-term stability,as it maintained 90%initial efficiency over 500 h and controlled storage at around 45%relative humidity and 25℃.

Electric-Field-Assisted Growth of Ga-Doped ZnO Nanorods Arrays for Dye-Sensitized Solar Cells

A photoanode with Ga-doped ZnO nanorods has been prepared on F-doped SnO2 (FTO) coated glass substrate and its application in dye-sensitized solar cells (DSSCs) has been investigated. Ga-doped ZnO nanorods have been synthesized by an electric-field-assisted wet chemical approach at 80?C. Under a direct current electric field, the nanorods predominantly grow on cathodes. The results of the X-ray photoelectron spectroscopy and photoluminescence verify that Ga dopant is successfully incorporated into the ZnO wurtzite lattice structure. Finally, employing Ga-doped ZnO nanorods with the length of ~5 μm as the photoanode of DSSCs, an overall energy conversion efficiency of 2.56% is achieved. The dramatically improved performance of Ga-doped ZnO based DSSCs compared with that of pure ZnO is due to the higher electron conductivity.

Tetraphenylethylene-doped covalent organic frameworks as a highly efficient aggregation-induced electrochemiluminescence emitter for ultrasensitive miRNA-21 analysis

MicroRNAs(miRNAs)as a well-known kind of cancer marker are closely associated with the formation and metastasis of tumors.Here,a novel tetraphenylethylene(TPE)-doped covalent organic frameworks(TPE-COFs)with strong aggregation-induced electrochemiluminescence(AIECL)response was synthesized and introduced to construct an ultrasensitive biosensor for the detection of miRNA-21.The strong aggregation-induced emission(AIE)response was obtained because the molecular motion of TPE was restricted by COFs which had the porosity and highly ordered topological structure.Meanwhile,the porous structure of COFs allowed TPE to react with electrochemiluminescence(ECL)coreactants more effectively.Furthermore,COFs significantly improved the electron transport efficiency of the entire ECL system.All of these endowed the TPE-COFs with superior AIECL performance.Then,a TPE-COFs based ECL resonance energy transfer(ECL-RET)system was constructed for ultrasensitive miRNA-21 biosensing with differential signal readout.The proposed assays exhibited excellent sensitivity with a wide dynamic range from 10 aM to 1 pM and a low detection limit of 2.18 aM.Therefore,these indicated that doping TPE in COFs was a creative way to develop functional COFs and provided an effective way for enhancing AIECL.Furthermore,this work boarded the application of AIECL in analytical chemistry.

Recent advances in carbonized non-noble metal–organic frameworks for electrochemical catalyst of oxygen reduction reaction

The non-noble metal oxygen reduction reaction(ORR) catalysts prepared by carbonization of metal–organic framework(MOF) have attracted more and more attentions in the fields of fuel cells and metal-air batteries due to their unique intrinsic advantages such as high catalytic activity, low price, simple synthesis and good adaptability. Different from the study of traditional high active noble metal catalysts, this review systematically summarizes recent developments on non-noble metal(Fe,Co, Cu, Ni, Mn and Mo) ORR catalysts prepared by various MOFs carbonization in different metal centers. The effects of synthesis strategies and pyrolysis conditions on the catalyst properties are discussed. Meanwhile, the key parameters of catalytic performances(including active sites, dispersed state and specific surface area) are discussed and the prospect is presented. It is expected that this review will provide effective guidance for future studies on carbonized non-noble MOFs for ORR electrochemical catalyst.

Bio-soft matter derived from traditional Chinese medicine:Characterizations of hierarchical structure,assembly mechanism,and beyond

Structural and functional explorations on bio-soft matter such as micelles,vesicles,nanoparticles,aggregates or polymers derived from traditional Chinese medicine(TCM)has emerged as a new topic in the field of TCM.The discovery of such cross-scaled bio-soft matter may provide a unique perspective for unraveling the new effective material basis of TCM as well as developing innovative medicine and biomaterials.Despite the rapid rise of TCM-derived bio-soft matter,their hierarchical structure and assembly mechanism must be unambiguously probed for a further in-depth understanding of their pharmacological activity.In this review,the current emerged TCM-derived bio-soft matter assembled from either small molecules or macromolecules is introduced,and particularly the unambiguous elucidation of their hierarchical structure and assembly mechanism with combined electron microscopic and spectroscopic techniques is depicted.The pros and cons of each technique are also discussed.The future challenges and perspective of TCM-derived bio-soft matter are outlined,particularly the requirement for their precise in situ structural determination is highlighted.

Combination of solution-phase process and halide exchange for all-inorganic, highly stable CsPbBr_3 perovskite nanowire photodetector

The synthesis of high quality all-inorganic perovskite nanowires needs the harsh conditions,complex process and precision instruments,which are not beneficial to their extensive application.Here,all-inorganic perovskite ce- sium lead bromine (CsPbBr3)nanowires (NWs)are demonstrated with the combination of solution-phase process and halide exchange technology.A metal-semiconductor-metal structure CsPbBr3 nanowire photodetector was prepared, which showed a detectivity as high as 1.7×10^11 cm Hz^1/2W^-1 (Jones)with rapid response time (The rise and decay time are 10ms and 22 ms,respectively).Moreover,our photodetectors have high stability under ultraviolet (UV)light,high temperature and humidity.

Photothermy-strengthened photocatalytic activity of polydopamine-modified metal-organic frameworks for rapid therapy of bacteria-infected wounds

Herein,a metal-organic framework(MOF)was modified using polydopamine(PDA)to develop the MOFPDA as a photoresponsive bacteria-killing agent under 660 nm light irradiation.The modification using PDA led to the production of not only more heat,but also much more~1O_(2).This is because the PDA could interact with the porphyrin ring of the MOF throughπ-πinteraction and the charge transfer between PDA and the MOFs decreases the ene rgy of the band of hybrid nanoparticles.In addition,greater levels of hyperthermia induced by PDA modification accelerated the charge trans fe r,which significantly strengthened the photocatalytic perfo rmance of MO F-PDA.Furthermore,after modification,the light abso rbance and water dispersibility of nanoparticles were both enhanced;both are important for the improvement of photocatalytic and photothermal properties.Consequently,MOF-PDA exhibited the highly effective antibacterial efficacy of 99.62%and 99.97%against Staphylococcus aureus and Escherichia coli,respectively,under 20 min 660 nm light irradiation.

Core-satellite metal-organic framework@upconversion nanoparticle superstructures via electrostatic self-assembly for efficient photodynamic theranostics

The nanoplatforms based on upconversion nanoparticles(UCNPs)have shown great promise in amplified photodynamic therapy(PDT)triggered by near-infrared(NIR)light.However,their practical in vivo applications are hindered by the overheating effect of 980 nm excitation and low utilization of upconversion luminescence(UCL)by photosensitizers.To solve these defects,core-satellite metal-organic framework@UCNP superstructures,composed of a single metal-organic framework(MOF)NP as the core and Nd3+-sensitized UCNPs as the satellites,are designed and synthesized via a facile electrostatic self-assembly strategy.The superstructures realize a high co-loading capacity of chlorin e6(Ce6)and rose bengal(RB)benefitted from the highly porous nature of MOF NPs,showing a strong spectral overlap between maximum absorption of photosensitizers and emission of UCNPs.The in vitro and in vivo experiments demonstrate that the dual-photosensitizer superstructures have trimodal(magnetic resonance(MR)/UCL/fluorescence(FL))imaging functions and excellent antitumor effectiveness of PDT at 808 nm NIR light excitation,avoiding the laser irradiation-induced overheating issue.This study provides new insights for the development of highly efficient PDT nanodrugs toward precision theranostics.

Synthesis of Bi2S3/carbon nanocomposites as anode materials for lithium-ion batteries

Metal sulfides such as Bismuth sulfide(Bi2 S3) hold immense potential to be promoted as anode materials for lithium-ion batteries(LIBs),owing to their high theoretical gravimetric and volumetric capacities.However,the poor electrical conductivity and volume expansion during cycling hinder the practical applications of Bi2 S3.In this work,we used pyrrole and glucose as carbon source to design the surface carbon coating on the surface of Bi2 S3 particles,to improve the structural stability of Bi2 S3.Two composite materials were synthesized-Bi2 S3 coated with nitrogen doped carbon(Bi2 S3@NC),and Bi2 S3 coated with carbon(Bi2 S3@C).When used as anode active materials,both Bi2 S3@NC and Bi2 S3@C showed improved performance compared to Bi2 S3,which confirms surface carbon coating as an effective and scalable way for the modification of Bi2 S3 material.The electrode based on Bi2 S3@NC materials demonstrated higher performance than that of Bi2 S3@C,with an initial discha rge capacity of 1126.5 mA h/g,good cycling stability(500 mA h/g after 200 cycles at 200 mA/g) and excellent rate capability.Finally,Li storage and migration mechanisms in Bi2 S3 are revealed using first principle density functional theory calculations.

Interaction in Binary Mixtures of Gemini Surfactant G12-6-12 and CTAB by NMR

The interaction between N, N′-bis（dimethyldodecyl）-1,6-hexanediammoniumdibromide （G12-6-12） and cetyltrimethylammonium bromide （CTAB） in D20 aqueous medium has been investigated by NMR at 298 K. The G12-6-12 and CTAB are about 0.773 and measured critical micelle concentration （cmc） of 0.668 mmol/L, respectively. The cmc^＊ （cmc of mixture） values are less than CMC^＊ （cmc of ideally mixed solution） in the mixed system, and the interaction parameter βM〈0 at different molar fractions α of G12-6-12 in the mixed systems, but just when α≤0.3, cmc^＊ values are much smaller than CMC^＊, and βM satisfies the relation of ｜βM｜〉｜ln（cmc1/cmc2）｜ （cmcl： cmc of pure G12-6-12 and cmc2： cmc Of pure CTAB）. The results indicate that there exists synergism between G12-6-12 and CTAB, and they can form mixed micelles, which is further proven by 2D NOESY and self-diffusion coefficient D experiments. There are intermolecular cross peaks between G12-6-12 and CTAB in 2D NOESY, and the radius of micelles in mixed solution is bigger than that in G12-6-12 pure solution in D experiments, indicating there are mixed micelles. However, when α〉0.3, we find that cmc^＊≈CMC^＊, βM≈0, obviously, the two surfactants are almost ideal mixing fitting the pseudo-phase separation model and regular solution theory.