High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)m...High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)membranes doped with barium titanate(BTO)nanoparticles and multi-walled carbon nanotubes(MWCNTs).The piezoelectric BTO nanoparticles were incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity and MWCNTs were incorporated to provide a microcapacitor structure for enhancing the performance of TENGs.When the mass fraction of the BTO nanoparticle was 10%and the mass fraction of the MWCNT was 0.1%,the corresponding TENG achieved optimum electric outputs(an open-circuit voltage of around 65 V,a short-circuit current of about 20.0μA and a transferred charge of about 25.0 nC),much higher than those of the TENG with a single PI membrane.The TENG is potentially used to supply energy for commercial light-emitting diodes and as self-powered sensors to monitor human physical training conditions.This research provides a guideline for developing TENGs with high performance,which is crucial for their long-term use.展开更多
The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and ...The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.展开更多
Designing and preparing a compatible electromagnetic interference(EMI)shielding,radar and infrared stealth material exhibits significant prospect in the military field.Hence,a novel conductive/magnetic polyimide-based...Designing and preparing a compatible electromagnetic interference(EMI)shielding,radar and infrared stealth material exhibits significant prospect in the military field.Hence,a novel conductive/magnetic polyimide-based nonwoven fabric(PFN_y)is prepared by alkali treatment,Fe~(3+)ion exchange,thermal reduction,and electroless nickel(Ni)plating process.Its impedance/insulation characteristics can be easily adjusted by controlling the in situ growth of Fe_(3)O_(4) and electroless nickel plating.Subsequently,a new strategy of constructing hierarchical dual-gradient impedance/insulation structure is implemented to achieve EMI shielding,radar and infrared stealth via stacking PFN_y with gradually decreased impedance/insulation characteristics from top to bottom.The formation of impedance matching gradient structure promotes effective introduction and dissipation of electromagnetic waves,endowing the composite with outstanding EMI shielding and radar stealth performance.Meanwhile,the construction of thermal insulation gradient structure can effectively inhibit thermal radiation from target,bringing an excellent infrared stealth performance.Importantly,the strong interfacial interactions between Fe_(3)O_(4),Ni and polyimide fiber accelerate PFNy to resist the stresses originated from high-temperature heat source,achieving a compatible high-temperature resistant radar/infrared stealth performance.Such excellent comprehensive properties endow it with a great potential in high-temperature military camouflage applications against enemy radar and infrared detection.展开更多
The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of...The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of CNTs were systematically investigated.The introduction of CNTs effectively refined the grains,weakened the texture and enhanced the microstructure homogeneity of the weld,which contributed to the enhancement of corrosion resistance.Specifically,the corrosion rates of hydrogen evolution and weight loss of weld decreased by>30%after the addition of CNTs,and the corrosion products were denser due to the formation of Al_(2)O_(3)passive film.The corrosion current density and polarization resistance of weld with addition of CNTs were 1.220μA/cm^(2)and 7155·cm^(2),respectively,in contrast to 2.480μA/cm^(2)and approximately 269.5·cm^(2)for the weld without CNTs.Besides,the content of precipitates in the weld increased from 0.60%to 1.76%after the addition of CNTs,which can release Al^(3+)ions,promoting the formation of a dense Al_(2)O_(3)film that serves to protect the metal matrix from further degradation.展开更多
Magnesium-based anode materials have attracted significant attention in the energy storage domain because of their high theoretical capacities and low electrochemical potentials.However,in conventional electrolyte sys...Magnesium-based anode materials have attracted significant attention in the energy storage domain because of their high theoretical capacities and low electrochemical potentials.However,in conventional electrolyte systems,magnesium metal electrodes dynamically generate an ion-blocking surface layer,resulting in prominent voltage polarization,which severely limits their practical applications.In this study,ZIF-8/carbon nanotubes(CNTs)coatings were used to modify the anodes of magnesium batteries.Compared with the unaltered magnesium battery,the voltage lag time of the ZIF-8/CNTs coating was shortened from 4 s before modification to 0.26 s,and the battery impedance was lowered by two orders of magnitude.The duration of the discharge platform was increased from 4 h before modification to 6-10 h,the anode utilization rate was more than doubled,and the specific energy density was significantly enhanced compared with the battery before modification.The mechanism indicates that the ZIF-8/CNTs coating can limit the infiltration of corrosive substances,extend their transmission path,and offer more effective protection to the magnesium anode.The incorporation of CNTs improves the conductivity of the battery,and it significantly improves the electrochemical performance of the magnesium battery.展开更多
Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling ...Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling and can show abnormal activation under pathological conditions.Our bibliometric analysis indicated a substantial increase in research on tunneling nanotubes over the past two decades,highlighting their important role in cellular communication.This review focuses on the formation of tunneling nanotubes in various types of glial cells,including astrocytes,microglia,glioma cells,and Schwann cells,as well as their roles in cellular communication and cargo transport.We found that glial cells influence the stability of the neural system and play a role in nerve regeneration through tunneling nanotubes.Tunneling nanotubes facilitate the transmission and progression of diseases by transporting pathogens and harmful substances.However,they are also involved in alleviating cellular stress by removing toxins and delivering essential nutrients.Understanding the interactions between glial cells through tunneling nanotubes could provide valuable insights into the complex neural networks that govern brain function and responses to injury.展开更多
Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechan...Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechanical strength,and chemical stability,making them suitable for many uses in energy storage,such as lithium-ion batteries(LIBs).Currently,their use in LIBs mainly focuses on conductive networks,current collectors,and dry electrodes.The review outlines advances in the use of CNTs in the cathodes and anodes of LIBs,especially in the electrode fabrication and mechanical sensors,as well as providing insights into their future development.展开更多
Designing and manufacturing compatible multi-band stealth materials remains a great challenge. In this work, a silver-metalized polyimide photochromic composite foam is successfully fabricated by self-activating elect...Designing and manufacturing compatible multi-band stealth materials remains a great challenge. In this work, a silver-metalized polyimide photochromic composite foam is successfully fabricated by self-activating electroless silver-plating on the surface of the polyimide skeleton and followed by applying a photochromic coating on the upper surface. The effective loading of silver nanoparticles facilitates the rational construction of a conductive network in foam, improving the efficient dissipation of incident electromagnetic waves. In addition, the interconnected conductive network successfully endows it with an excellent Joule heating capability, which can be employed to effectively remove ice and/or mitigate the impact of water vapor on radar stealth performance in cold and wet weather. Besides, the low emissivity silver plating combined with superior thermal insulation of foam enables the material with excellent infrared stealth performance. Moreover, the modulation of self-adaptive photochromic coating brings a prominent visual stealth performance under different sunlight backgrounds. As a result, such excellent radar and infrared stealth performance combined with the adaptive color-switching capability provides the foam with great potential for preparing compatible multi-band materials.展开更多
Carbon nanotubes(CNTs)have many excellent properties that make them ideally suited for use in lithium-ion batteries(LIBs).In this review,the recent research on applications of CNTs in LIBs,including their usage as fre...Carbon nanotubes(CNTs)have many excellent properties that make them ideally suited for use in lithium-ion batteries(LIBs).In this review,the recent research on applications of CNTs in LIBs,including their usage as freestanding anodes,conductive additives,and current collectors,are discussed.Challenges,strategies,and progress are analyzed by selecting typical examples.Particularly,when CNTs are used with relatively large mass fractions,the relevant interfacial electrochemistry in such a CNT-based electrode,which dictates the quality of the resulting solid-electrolyte interface,becomes a concern.Hence,in this review the different lithium-ion adsorption and insertion mechanisms inside and outside of CNTs are compared;the influence of not only CNT structural features(including their length,defect density,diameter,and wall thickness)but also the electrolyte composition on the solid-electrolyte interfacial reactions is analyzed in detail.Strategies to optimize the solid-solid interface between CNTs and the other solid components in various composite electrodes are also covered.By emphasizing the importance of such a structure-performance relationship,the merits and weaknesses of various applications of CNTs in various advanced LIBs are clarified.展开更多
In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electrom...In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.展开更多
Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,...Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,a hierarchical polyimide(PI)nonwoven fabric is fabricated by alkali treatment,in-situ growth of magnetic particles and"self-activated"electroless Ag plating process.Especially,the hierarchical impedance matching can be constructed by systematically assembling Fe_(3)O_(4)/Ag-loaded PI nonwoven fabric(PFA)and pure Ag-coated PI nonwoven fabric(PA),endowing it with an ultralowreflectivity EMI shielding performance.In addition,thermal insulation of fluffy three-dimensional(3D)space structure in PFA and low infrared emissivity of PA originated from Ag plating bring an excellent infrared stealth performance.More importantly,the strong bonding interaction between Fe_(3)O_(4),Ag,and PI fiber improves thermal stability in EMI shielding and high-temperature resistant infrared stealth performance.Such excellent comprehensive performance makes it promising for military tents to protect internal equipment from electromagnetic interference stemmed from adjacent equipment and/or enemy,and inhibit external infrared detection.展开更多
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was propo...The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.展开更多
The features of additive manufacturing(AM)have made commercially pure titanium(CP-Ti)an attractive candidate material for biomedical implants.However,achieving high strength and ductility is challenging because of the...The features of additive manufacturing(AM)have made commercially pure titanium(CP-Ti)an attractive candidate material for biomedical implants.However,achieving high strength and ductility is challenging because of the columnar structures and fine martensite formation.This study investigated the effect of carbon nanotubes(CNTs)addition on the microstructure and mechanical properties of grade 1 CP-Ti(Gr-1)during the laser powder bed fusion(L-PBF)process.A minute amount of 0.2%mass fraction(wt%)CNTs addition resulted in a high yield strength of approximately 700 MPa and exceptional ductility of 25.7%.Therein,a portion of the CNTs dissolved in the matrix as solute atoms,contributing to solution strengthening,while others were transformed into Ti C_(x)through an in situ reaction with the Ti matrix.Furthermore,the addition of CNTs resulted in the formation of a larger fraction of equiaxed grains and increased the activity of basal and prismatic slip systems.Hence,Gr-1 with CNTs exhibited significantly increased ductility while maintaining a high strength comparable to that of Gr-1 without CNTs.The insights gained from this study provide a novel approach for designing strong and ductile Ti alloys for AM.展开更多
Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid ...Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid boron.In this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system.This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems.These growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains.These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.展开更多
A series of polyimide（PI）/multi-walled carbon nanotube（MWCNT） composite fibers were prepared by copolymerizing a mixture of monomers and carboxylic-functionalized MWCNTs, followed by dry-jet wet spinning, thermal ...A series of polyimide（PI）/multi-walled carbon nanotube（MWCNT） composite fibers were prepared by copolymerizing a mixture of monomers and carboxylic-functionalized MWCNTs, followed by dry-jet wet spinning, thermal imidization, and hot-drawing process. The content of the carboxylic groups of MWCNTs significantly increased when treated with mixed acid, whereas their length decreased with treatment time. Both the carboxylic content and length of MWCNTs influenced the mechanical properties of the composite fibers. Fiber added with 0.1 wt% MWCNTs treated for 4 h exhibited the best mechanical properties, i.e., 1.4 GPa tensile strength and 14.30% elongation at break, which were 51% and 32% higher than those of pure PI fibers, respectively. These results indicated that a suitable MWCNT content strengthened and toughened the resultant PI composite fibers, simultaneously. Moreover, raising draw ratio resulted in the increase of tensile strength and tensile modulus of the composite fibers.展开更多
The sensitive and selective monitoring of nitrogen dioxide(NO_(2))can have a significant impact on environmental monitoring and health protection.Unfortunately,commercial NO_(2)sensors largely suffer from poor detecti...The sensitive and selective monitoring of nitrogen dioxide(NO_(2))can have a significant impact on environmental monitoring and health protection.Unfortunately,commercial NO_(2)sensors largely suffer from poor detection sensitivity and high operating temperatures.In this study,we developed a sensitive roomtemperature NO_(2)sensor based on an n-n heterojunction comprised of a Cs_(2)AgInCl_(6)perovskite with chlorine vacancies(VCl)and TiO_(2)nanotube arrays(VCl-Cs_(2)AgInCl_(6)/TiO_(2)NTs).In this design,the large number of chlorine vacancies in the Cs_(2)AgInCl_(6)perovskite act as active sites for oxygen adsorption and the subsequent sensing reaction.Benefitting from the formation of the n-n type heterojunction and the onedimensional structure of the TiO_(2)nanotubes,the Fermi levels are aligned,thereby facilitating the efficient transport of charge carriers between the target gas and the sensing interface.The resulting VClCs_(2)Ag In Cl_(6)/TiO_(2)NTs demonstrate a high response of 7.26 toward 1 ppm of NO_(2)at room temperature,possess a detection limit as low as 20 ppb,and have outstanding performance stability.This work widens the application of perovskite materials and indicates their potential application in medical diagnostics,environmental monitoring,and smart sensing systems.展开更多
The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compressio...The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.展开更多
Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discu...Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.展开更多
In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a que...In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a quencher to construct a chiral sensor for detecting histidine(His)enantiomers.Competitive interactions between Fc and His induce partial Fc desorption from the sensor surface,leading to ECL signal recovery.Differential Fc release due to the distinct binding affinities of Zn-Dcam-dabco for His enantiomers enabled precise chiral discrimination.Notably,the sensor achieved the quantitative detection of His enantiomers with an limits of detection(LOD)of 8μmol/L.Furthermore,the sensor demonstrated excellent recovery rates of 98.0%–104%for l-histidine(L-His)and 92.0%–95.9%for D-His in spiked milk samples,validating its reliability for real-sample analysis.This study provides a promising platform for ECL-based chiral recognition,bioanalysis,and the rapid assessment of amino acids in food products.展开更多
Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friend...Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friendliness,and cost effectiveness.However,the inherent shortcomings of organic electrodes,such as low conductivity,high solubility in electrolyte,narrow material utilization,etc.,limit their further development.In this work,we successfully prepared a novel porous polyimide PPD containing multicarbonyl active centers via the polycondensation of pyromellitic dianhydride(PMDA)and2,6-diaminoanthraquinone(DAAQ).The stable conjugated structure and multiple redox centers give the polymer high reversible specific capacity(244.6 m Ah/g after 100 cycles at 100 m A/g),ultra-long cycle stability(100.7 m Ah/g after 2000 cycles at 1.0 A/g),and predominant rate capability.Meanwhile,the sodium storage mechanism of the electrode materials during the charging and discharging process is investigated by ex-situ XPS/FTIR analysis.Due to the exceptional electrochemical properties and simple synthesis method,this work may shed light on the preparation of polyimide-based anodes for high specific capacity and rate capability secondary batteries.展开更多
基金National Natural Science Foundation of China(No.52103267)。
文摘High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)membranes doped with barium titanate(BTO)nanoparticles and multi-walled carbon nanotubes(MWCNTs).The piezoelectric BTO nanoparticles were incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity and MWCNTs were incorporated to provide a microcapacitor structure for enhancing the performance of TENGs.When the mass fraction of the BTO nanoparticle was 10%and the mass fraction of the MWCNT was 0.1%,the corresponding TENG achieved optimum electric outputs(an open-circuit voltage of around 65 V,a short-circuit current of about 20.0μA and a transferred charge of about 25.0 nC),much higher than those of the TENG with a single PI membrane.The TENG is potentially used to supply energy for commercial light-emitting diodes and as self-powered sensors to monitor human physical training conditions.This research provides a guideline for developing TENGs with high performance,which is crucial for their long-term use.
基金financially supported by the National Key R&D Program of China(No.2023YFB3812400)the National Natural Science Foundation of China(No.51890871)the GJYC Program of Guangzhou(No.2024D02J0004)。
文摘The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.
基金the financial support from China Postdoctoral Science Foundation(2024M760348)National Natural Science Foundation of China(52373077)。
文摘Designing and preparing a compatible electromagnetic interference(EMI)shielding,radar and infrared stealth material exhibits significant prospect in the military field.Hence,a novel conductive/magnetic polyimide-based nonwoven fabric(PFN_y)is prepared by alkali treatment,Fe~(3+)ion exchange,thermal reduction,and electroless nickel(Ni)plating process.Its impedance/insulation characteristics can be easily adjusted by controlling the in situ growth of Fe_(3)O_(4) and electroless nickel plating.Subsequently,a new strategy of constructing hierarchical dual-gradient impedance/insulation structure is implemented to achieve EMI shielding,radar and infrared stealth via stacking PFN_y with gradually decreased impedance/insulation characteristics from top to bottom.The formation of impedance matching gradient structure promotes effective introduction and dissipation of electromagnetic waves,endowing the composite with outstanding EMI shielding and radar stealth performance.Meanwhile,the construction of thermal insulation gradient structure can effectively inhibit thermal radiation from target,bringing an excellent infrared stealth performance.Importantly,the strong interfacial interactions between Fe_(3)O_(4),Ni and polyimide fiber accelerate PFNy to resist the stresses originated from high-temperature heat source,achieving a compatible high-temperature resistant radar/infrared stealth performance.Such excellent comprehensive properties endow it with a great potential in high-temperature military camouflage applications against enemy radar and infrared detection.
基金supported by the National Natural Science Foundation of China(grant nos.52275364 and 52025052)。
文摘The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of CNTs were systematically investigated.The introduction of CNTs effectively refined the grains,weakened the texture and enhanced the microstructure homogeneity of the weld,which contributed to the enhancement of corrosion resistance.Specifically,the corrosion rates of hydrogen evolution and weight loss of weld decreased by>30%after the addition of CNTs,and the corrosion products were denser due to the formation of Al_(2)O_(3)passive film.The corrosion current density and polarization resistance of weld with addition of CNTs were 1.220μA/cm^(2)and 7155·cm^(2),respectively,in contrast to 2.480μA/cm^(2)and approximately 269.5·cm^(2)for the weld without CNTs.Besides,the content of precipitates in the weld increased from 0.60%to 1.76%after the addition of CNTs,which can release Al^(3+)ions,promoting the formation of a dense Al_(2)O_(3)film that serves to protect the metal matrix from further degradation.
基金supported by the Guangxi Natural Science Foundation,China(No.2020GXNSFAA 159011)the National Natural Science Foundation of China(No.51664011).
文摘Magnesium-based anode materials have attracted significant attention in the energy storage domain because of their high theoretical capacities and low electrochemical potentials.However,in conventional electrolyte systems,magnesium metal electrodes dynamically generate an ion-blocking surface layer,resulting in prominent voltage polarization,which severely limits their practical applications.In this study,ZIF-8/carbon nanotubes(CNTs)coatings were used to modify the anodes of magnesium batteries.Compared with the unaltered magnesium battery,the voltage lag time of the ZIF-8/CNTs coating was shortened from 4 s before modification to 0.26 s,and the battery impedance was lowered by two orders of magnitude.The duration of the discharge platform was increased from 4 h before modification to 6-10 h,the anode utilization rate was more than doubled,and the specific energy density was significantly enhanced compared with the battery before modification.The mechanism indicates that the ZIF-8/CNTs coating can limit the infiltration of corrosive substances,extend their transmission path,and offer more effective protection to the magnesium anode.The incorporation of CNTs improves the conductivity of the battery,and it significantly improves the electrochemical performance of the magnesium battery.
基金supported by the National Natural Science Foundation of China,No.82101115(to JY)the Wuhan University Independent Innovation Fund Youth Project,No.2042021kf0094(to JY).
文摘Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling and can show abnormal activation under pathological conditions.Our bibliometric analysis indicated a substantial increase in research on tunneling nanotubes over the past two decades,highlighting their important role in cellular communication.This review focuses on the formation of tunneling nanotubes in various types of glial cells,including astrocytes,microglia,glioma cells,and Schwann cells,as well as their roles in cellular communication and cargo transport.We found that glial cells influence the stability of the neural system and play a role in nerve regeneration through tunneling nanotubes.Tunneling nanotubes facilitate the transmission and progression of diseases by transporting pathogens and harmful substances.However,they are also involved in alleviating cellular stress by removing toxins and delivering essential nutrients.Understanding the interactions between glial cells through tunneling nanotubes could provide valuable insights into the complex neural networks that govern brain function and responses to injury.
文摘Energy storage is a key factor in the drive for carbon neutrality and carbon nanotubes(CNTs)may have an important role in this.Their intrinsic sp2 covalent structure gives them excellent electrical conductivity,mechanical strength,and chemical stability,making them suitable for many uses in energy storage,such as lithium-ion batteries(LIBs).Currently,their use in LIBs mainly focuses on conductive networks,current collectors,and dry electrodes.The review outlines advances in the use of CNTs in the cathodes and anodes of LIBs,especially in the electrode fabrication and mechanical sensors,as well as providing insights into their future development.
基金supported by the National Natural Science Foundation of China(Nos.52373077,52003106,52233006,and 52161135302)the Research Foundation Flanders(No.G0F2322N)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1236)the Innovation Program of Shanghai Municipal Education Commission(No.2021-01-07-00-03-E00108).
文摘Designing and manufacturing compatible multi-band stealth materials remains a great challenge. In this work, a silver-metalized polyimide photochromic composite foam is successfully fabricated by self-activating electroless silver-plating on the surface of the polyimide skeleton and followed by applying a photochromic coating on the upper surface. The effective loading of silver nanoparticles facilitates the rational construction of a conductive network in foam, improving the efficient dissipation of incident electromagnetic waves. In addition, the interconnected conductive network successfully endows it with an excellent Joule heating capability, which can be employed to effectively remove ice and/or mitigate the impact of water vapor on radar stealth performance in cold and wet weather. Besides, the low emissivity silver plating combined with superior thermal insulation of foam enables the material with excellent infrared stealth performance. Moreover, the modulation of self-adaptive photochromic coating brings a prominent visual stealth performance under different sunlight backgrounds. As a result, such excellent radar and infrared stealth performance combined with the adaptive color-switching capability provides the foam with great potential for preparing compatible multi-band materials.
基金Xiamen Science and Technology Project,Grant/Award Number:3502Z20231057National Key Research and Development Program of China,Grant/Award Number:3502Z20231057National Natural Science Foundation of China,Grant/Award Numbers:22279107,22288102。
文摘Carbon nanotubes(CNTs)have many excellent properties that make them ideally suited for use in lithium-ion batteries(LIBs).In this review,the recent research on applications of CNTs in LIBs,including their usage as freestanding anodes,conductive additives,and current collectors,are discussed.Challenges,strategies,and progress are analyzed by selecting typical examples.Particularly,when CNTs are used with relatively large mass fractions,the relevant interfacial electrochemistry in such a CNT-based electrode,which dictates the quality of the resulting solid-electrolyte interface,becomes a concern.Hence,in this review the different lithium-ion adsorption and insertion mechanisms inside and outside of CNTs are compared;the influence of not only CNT structural features(including their length,defect density,diameter,and wall thickness)but also the electrolyte composition on the solid-electrolyte interfacial reactions is analyzed in detail.Strategies to optimize the solid-solid interface between CNTs and the other solid components in various composite electrodes are also covered.By emphasizing the importance of such a structure-performance relationship,the merits and weaknesses of various applications of CNTs in various advanced LIBs are clarified.
基金supported by the Natural Science Foundation of Shanxi Province(Nos.20210302123015 and 20210302123035)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-06)the Open Foundation of China-Belarus Belt and Road Joint Laboratory on Electromagnetic Environment Effect(No.ZBKF2022030301).
文摘In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.
基金support from the National Natural Science Foundation of China(52373077,52003106,52103074,52233006,52161135302)the Research Foundation Flanders(G0F2322N)Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-03-E00108).
文摘Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,a hierarchical polyimide(PI)nonwoven fabric is fabricated by alkali treatment,in-situ growth of magnetic particles and"self-activated"electroless Ag plating process.Especially,the hierarchical impedance matching can be constructed by systematically assembling Fe_(3)O_(4)/Ag-loaded PI nonwoven fabric(PFA)and pure Ag-coated PI nonwoven fabric(PA),endowing it with an ultralowreflectivity EMI shielding performance.In addition,thermal insulation of fluffy three-dimensional(3D)space structure in PFA and low infrared emissivity of PA originated from Ag plating bring an excellent infrared stealth performance.More importantly,the strong bonding interaction between Fe_(3)O_(4),Ag,and PI fiber improves thermal stability in EMI shielding and high-temperature resistant infrared stealth performance.Such excellent comprehensive performance makes it promising for military tents to protect internal equipment from electromagnetic interference stemmed from adjacent equipment and/or enemy,and inhibit external infrared detection.
基金support from the Postgraduate Innovation Foundation of Xi'an Polytechnic University(No.chx2024034)the Natural Science Foundation of Shaanxi Province(No.2022JQ-362,2021JQ-677)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.21JK20180911).
文摘The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.
基金financially supported by the National Key Research and Development Project of the Ministry of Science and Technology of China(No.2022YFB4601000)the Fundamental Research Funds for the Central Universities(No.2042023kf0103)the Ministry of Trade,Industry and Energy,Korea(No.20013095)。
文摘The features of additive manufacturing(AM)have made commercially pure titanium(CP-Ti)an attractive candidate material for biomedical implants.However,achieving high strength and ductility is challenging because of the columnar structures and fine martensite formation.This study investigated the effect of carbon nanotubes(CNTs)addition on the microstructure and mechanical properties of grade 1 CP-Ti(Gr-1)during the laser powder bed fusion(L-PBF)process.A minute amount of 0.2%mass fraction(wt%)CNTs addition resulted in a high yield strength of approximately 700 MPa and exceptional ductility of 25.7%.Therein,a portion of the CNTs dissolved in the matrix as solute atoms,contributing to solution strengthening,while others were transformed into Ti C_(x)through an in situ reaction with the Ti matrix.Furthermore,the addition of CNTs resulted in the formation of a larger fraction of equiaxed grains and increased the activity of basal and prismatic slip systems.Hence,Gr-1 with CNTs exhibited significantly increased ductility while maintaining a high strength comparable to that of Gr-1 without CNTs.The insights gained from this study provide a novel approach for designing strong and ductile Ti alloys for AM.
基金supported by the National Natural Science Foundation of China(No.51972162)the Fundamental Research Funds for the Central Universities(No.2024300440).
文摘Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their development.The primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid boron.In this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system.This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems.These growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains.These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.
基金financially supported by the National Basic Research Program of China(No.2014CB643604)the National Natural Science Foundation of China(No.51173178)
文摘A series of polyimide（PI）/multi-walled carbon nanotube（MWCNT） composite fibers were prepared by copolymerizing a mixture of monomers and carboxylic-functionalized MWCNTs, followed by dry-jet wet spinning, thermal imidization, and hot-drawing process. The content of the carboxylic groups of MWCNTs significantly increased when treated with mixed acid, whereas their length decreased with treatment time. Both the carboxylic content and length of MWCNTs influenced the mechanical properties of the composite fibers. Fiber added with 0.1 wt% MWCNTs treated for 4 h exhibited the best mechanical properties, i.e., 1.4 GPa tensile strength and 14.30% elongation at break, which were 51% and 32% higher than those of pure PI fibers, respectively. These results indicated that a suitable MWCNT content strengthened and toughened the resultant PI composite fibers, simultaneously. Moreover, raising draw ratio resulted in the increase of tensile strength and tensile modulus of the composite fibers.
基金supported by the National Natural Science Foundation of China(No.22374015)the Fundamental Research Funds for the Central Universities(N2424020)+1 种基金Liaoning Province Foundation for Distinguished Young Scholars(No.1727146584490,to Y.-Y.Song)Liaoning Binhai laboratory(No.LBLG-2024-02)。
文摘The sensitive and selective monitoring of nitrogen dioxide(NO_(2))can have a significant impact on environmental monitoring and health protection.Unfortunately,commercial NO_(2)sensors largely suffer from poor detection sensitivity and high operating temperatures.In this study,we developed a sensitive roomtemperature NO_(2)sensor based on an n-n heterojunction comprised of a Cs_(2)AgInCl_(6)perovskite with chlorine vacancies(VCl)and TiO_(2)nanotube arrays(VCl-Cs_(2)AgInCl_(6)/TiO_(2)NTs).In this design,the large number of chlorine vacancies in the Cs_(2)AgInCl_(6)perovskite act as active sites for oxygen adsorption and the subsequent sensing reaction.Benefitting from the formation of the n-n type heterojunction and the onedimensional structure of the TiO_(2)nanotubes,the Fermi levels are aligned,thereby facilitating the efficient transport of charge carriers between the target gas and the sensing interface.The resulting VClCs_(2)Ag In Cl_(6)/TiO_(2)NTs demonstrate a high response of 7.26 toward 1 ppm of NO_(2)at room temperature,possess a detection limit as low as 20 ppb,and have outstanding performance stability.This work widens the application of perovskite materials and indicates their potential application in medical diagnostics,environmental monitoring,and smart sensing systems.
基金financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147)the Natural Science Foundation of Jiangsu Province,China(No.BK20220157)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202)the National Key Research and Development Program of China(No.2023YFC3804204)the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。
文摘The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.
基金supported by National Natural Science Foundation of China(22276144).
文摘Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.
基金financially supported by the Natural Science Foundation of Shandong Province,China(Nos.ZR2020QB065 and ZR2021MB121)。
文摘In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a quencher to construct a chiral sensor for detecting histidine(His)enantiomers.Competitive interactions between Fc and His induce partial Fc desorption from the sensor surface,leading to ECL signal recovery.Differential Fc release due to the distinct binding affinities of Zn-Dcam-dabco for His enantiomers enabled precise chiral discrimination.Notably,the sensor achieved the quantitative detection of His enantiomers with an limits of detection(LOD)of 8μmol/L.Furthermore,the sensor demonstrated excellent recovery rates of 98.0%–104%for l-histidine(L-His)and 92.0%–95.9%for D-His in spiked milk samples,validating its reliability for real-sample analysis.This study provides a promising platform for ECL-based chiral recognition,bioanalysis,and the rapid assessment of amino acids in food products.
基金supported by National Natural Science Foundation,China(Nos.52071132,U21A20284 and 52261135632)Natural Science Foundation of Henan,China(Nos.232300421080,242300421035)+2 种基金Program for Innovative Team(in Science and Technology)in University of Henan Province,China(No.24IRTSTHN006)Key Scientific Research Programs in Universities of Henan Province,China–Special Projects for Basic Research(No.23ZX008)the Natural Science Foundation of Hunan Province,China(No.2023JJ50287)。
文摘Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friendliness,and cost effectiveness.However,the inherent shortcomings of organic electrodes,such as low conductivity,high solubility in electrolyte,narrow material utilization,etc.,limit their further development.In this work,we successfully prepared a novel porous polyimide PPD containing multicarbonyl active centers via the polycondensation of pyromellitic dianhydride(PMDA)and2,6-diaminoanthraquinone(DAAQ).The stable conjugated structure and multiple redox centers give the polymer high reversible specific capacity(244.6 m Ah/g after 100 cycles at 100 m A/g),ultra-long cycle stability(100.7 m Ah/g after 2000 cycles at 1.0 A/g),and predominant rate capability.Meanwhile,the sodium storage mechanism of the electrode materials during the charging and discharging process is investigated by ex-situ XPS/FTIR analysis.Due to the exceptional electrochemical properties and simple synthesis method,this work may shed light on the preparation of polyimide-based anodes for high specific capacity and rate capability secondary batteries.
