Thermal stability of perovskite materials is an issue impairing the long-term operation of inverted perovskite solar cells(PSCs). Herein, the thermal attenuation mechanism of the MAPb I3films that deposited on two dif...Thermal stability of perovskite materials is an issue impairing the long-term operation of inverted perovskite solar cells(PSCs). Herein, the thermal attenuation mechanism of the MAPb I3films that deposited on two different hole transport layers(HTL), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS) and poly(3,4-ethylenedioxythiophene)(PEDOT), is comprehensively studied by applying a heat treatment at 85℃. The thermal stress causes the mutual ions migration of I, Pb and Ag through the device, which leads to the thermal decomposition of perovskite to form Pb I2. Interestingly, we find that I ions tend to migrate more towards electron transport layer(ETL) during heating, which is different with the observation of I ions migration towards HTL when bias pressure is applied. Moreover, the use of electrochemical deposited PEDOT as HTL significantly decreases the defect density of MAPb I3films as compared to PEDOT:PSS supported one. The electrochemical deposition PEDOT has good carrier mobility and low acidity, which avoids the drawbacks of aqueous PEDOT:PSS. Accordingly, the inverted PSCs based on PEDOT show superior durability than that with PEDOT:PSS. Our results reveal detailed degradation routes of a new kind of inverted PSCs which can contribute to the understanding of the failure of thermal-aged inverted PSCs.展开更多
A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr(wt.%) alloy is processed by solution treatment and high pressure torsion(HPT) at room temperature to produce a nanostructured light material with high hardness. The stability of this alloy ...A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr(wt.%) alloy is processed by solution treatment and high pressure torsion(HPT) at room temperature to produce a nanostructured light material with high hardness. The stability of this alloy is subsequently tested through isochronal annealing for 0.5 h at 373 K to 673 K. The results reveal a thermal stability that is vastly superior to that of conventional Mg-based alloys processed by severe plastic deformation: the grain size remains at around 50 nm on heating to 573 K, and as the temperature is increased to 673 K,grain growth is restricted to within 500 nm. The stability of grain refinement of the present alloy/processing combination allowing grain size to be limited to 55 nm after exposure at 573 K, appears to be nearly one order of magnitude better than for the other SPD processed Mg-RE type alloys, and 2 orders of magnitude better than those of SPD processed RE-free Mg alloys. This superior thermal stability is attributed to formation of co-clusters near and segregation at grain boundaries, which cause a thermodynamic stabilization of grain size, as well as formation of β-Mg_(5)RE equilibrium phase at grain boundaries, which impede grain growth by the Zener pinning effect. The hardness of the nanostructured Mg-Gd-Y-Zn-Zr alloy increases with increasing annealing temperature up to 573 K, which is quite different from the other SPD-processed Mg-based alloys. The high hardness of 136 HV after annealing at 573 K is mainly due to solute segregation and solute clustering at or near grain boundaries.展开更多
Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential dep...Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1. The film morphology can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer. Detailed morphology investigations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends. Consequently, the optimized all-PSCs delivered an enhanced power conversion efficiency(PCE) of 15.21%along with improved carrier extraction and suppressed charge recombination. More importantly, the optimized all-PSCs remain over 90% of their initial PCEs under continuous thermal stress at 65 °C for over 500 h. This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.展开更多
The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy bala...The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy balance and the energy-water transfer within soils. To clarify the thermal-moisture dynamics and thermal stability of the active layer in permafrost regions under wet/dry conditions, the verified water-vapour-heat coupling model was used. Changes in the surface energy balance, energy-water transfer within the soil, and thickness of the active layer were quantitatively analyzed. The results demonstrate that rainfall changes significantly affect the Bowen ratio, which in turn affects surface energy exchange. Under wet/dry conditions, there is a positive correlation between rainfall and liquid water flux under the hydraulic gradient;water vapour migration is the main form under the temperature gradient, which indicates that the influence of water vapour migration on thermalmoisture dynamics of the active layer cannot be neglected. Concurrently, regardless of wet or dry conditions,disturbance of the heat transport by conduction caused by rainfall is stronger than that of convection by liquid water. In addition, when rainfall decreases by 1.5 times(212 mm) and increases by 1.5 times(477 mm), the thickness of the active layer increases by 0.12 m and decreases by 0.21 m, respectively. The results show that dry conditions are not conducive to the preservation of frozen soil;however, wet conditions are conducive to the preservation of frozen soil, although there is a threshold value. When this threshold value is exceeded, rainfall is unfavourable for the development of frozen soil.展开更多
Macao Science Satellite-1(known as MSS-1)is a low-inclination mission that will be launched at the beginning of 2023.An optical bench is used for accessing high-precision strength and direction measurements of the mag...Macao Science Satellite-1(known as MSS-1)is a low-inclination mission that will be launched at the beginning of 2023.An optical bench is used for accessing high-precision strength and direction measurements of the magnetic field.In this paper,we present a thermal stability design for the optical bench based on quasi-kinematic support by kinematic hinges on the MSS-1.The change in angles with the finite element method(FEM)model modified by thermal deformation test data is analyzed.The robustness of the structure is also investigated via the Monte Carlo method.Two main results are obtained.First,the peak-to-peak value(Vp-p)of the inter-boresight angle is at most 1.24″,and the Vp-p of the inter-boresight angle modification and analysis is no more than 3.13″,both of which are better than those on the Swarm satellites in orbit.Second,the 90°fibers of the carbon-reinforced arm need to be strictly controlled during the technological process.展开更多
A set of hydrodynamic similarity laws is applied to the scale-up of ethylene polymerization fluidized bed reactors(FBRs)under the condensed mode operation.The thermal stability of open-loop controlled FBRs is investig...A set of hydrodynamic similarity laws is applied to the scale-up of ethylene polymerization fluidized bed reactors(FBRs)under the condensed mode operation.The thermal stability of open-loop controlled FBRs is investigated by the homotopy continuation method.And the Hopf bifurcation point is selected as an index of the thermal stability similarity.The simulation results show the similarity in state variables,operation parameters,the space-time yield(STY),and the thermal stability of FBRs with different scales.Furthermore,the thermal stability behaviors and similarity of the closed-loop controlled FBRs with different scales are analyzed.The observed similar trend of Hopf bifurcation curves reveals the similarity in the thermal stability of closed-loop controlled FBRs with different scaling ratios.In general,the results of the thermal stability similarity confirm that the hydrodynamics scaling laws proposed in the work are applicable to the scale-up of FBRs under the condensed mode operation.展开更多
This paper studies the effect of Ce on the thermal stability of the Ω phase in an Al-Cu-Mg-Ag alloy by TEM and tensile testing. It has been shown that Ce substantially increases the nucleation density of the Ω phase...This paper studies the effect of Ce on the thermal stability of the Ω phase in an Al-Cu-Mg-Ag alloy by TEM and tensile testing. It has been shown that Ce substantially increases the nucleation density of the Ω phase by acting as the heterogeneous nucleation center. Most impor-tantly,Ce improves the thermal stability of the Ω phase by decreasing the diffusion velocity of Cu atoms and increasing the energy barrier of the thickening ledge nucleation,thus improving the strength of the Al-Cu-Mg-Ag alloy at both room-and elevated-temperatures.展开更多
To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy_(80)Ga_(20)(at.%) powder.The ...To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy_(80)Ga_(20)(at.%) powder.The coercivity of the magnets increased from the undoped value of 12.72 kOe to a doped value of 21.44 kOe.A micro-structural analysis indicates that a well-developed core-shell structure forms in the magnets doped with Dy_(80)Ga_(20) powder.The improvement in magnetic properties is believed to be related to the refined and uniform matrix grains,continuous grain boundaries,and a hardened(Nd,Dy)_2Fe_(14)B shell surrounding the matrix grains.Additionally,the doped magnets exhibit an obvious improvement in thermal stability.For the magnets with added Dy_(80)Ga_(20) powder,the temperature coefficients of remanence(α) and coercivity(β) increased to-0.106%℃^(-1) and-0.60%℃^(-1) over the range 20-100 ℃,compared to temperature coefficients of-0.117%℃^(-1)(α) and-0.74%℃^(-1)(β) in the regular magnets without Dy_(80)Ga_(20) powder.The irreversible loss of magnetic flux(Hirr) was investigated at different temperatures.After being exposed to 150 ℃ for 2 h,the Hirr of magnets with 4 wt.%Dy_(80)Ga_(20) decreased by ~95%compared to that of the undoped magnets.The enhanced temperature coefficients and Hirr indicate improved thermal stability in the doped Nd-Fe-B magnets.The intergranular addition of Dy_(80)Ga_(20) also improved the corrosion resistance of the magnets because of the enhanced intergranular phase.In a corrosive atmosphere for 96 h,the mass loss of the sintered magnets with 4 wt.%Dy_(80)Ga_(20) was 2.68 mg/cm^2,less than 10%of that suffered by the undoped magnets(28.1 mg/cm^2).展开更多
A one-dimensional chain cobalt(II) coordination polymer with 2,4,6-trimethyl- benzoic acid, 4,4-bipyridine and cobalt perchlorate anhydrous has been synthesized and charac- terized in the mixture solvent of water and ...A one-dimensional chain cobalt(II) coordination polymer with 2,4,6-trimethyl- benzoic acid, 4,4-bipyridine and cobalt perchlorate anhydrous has been synthesized and charac- terized in the mixture solvent of water and alcohol. Crystal data for this complex: monoclinic, space group C2/c, a = 2.3805(8), b = 1.1464(4), c = 1.5807(5) nm, γ = 128.435(4)o, V = 3.3791(18) nm3, Dc = 1.246 g/cm3, Z = 4, F(000) = 1340, final GooF = 1.009, R = 0.0504 and wR = 0.1287. Structural analysis shows that the cobalt ion is coordinated with two nitrogen atoms of one 4,4- bipyridine molecule and four oxygen atoms from two 2,4,6-trimethylbenzoic acid molecules and two alcohol molecules, giving a distorted octahedral coordination geometry. The result of TG analysis indicates that the title complex is stable till 200 ℃.展开更多
Grain growth can modify the texture orientation and the fraction of different texture component.The thermal stability of two texture component in an extruded magnesium AZ31 alloy was investigated.Three types samples w...Grain growth can modify the texture orientation and the fraction of different texture component.The thermal stability of two texture component in an extruded magnesium AZ31 alloy was investigated.Three types samples with different texture distribution were prepared.The results show that normal grain growth takes place in the magnesium AZ31 alloy during annealing at 300℃ and 450℃.But the grain growth does not lead to the strengthening of either texture component.Both the<0002>⊥ED texture and<0002>//ED texture components show good thermal stability,without influence of the texture volume fraction.The two different texture component possess comparable boundary migration ability,so grains of the two texture component consume indifferently the other grains,or are equally consumed during annealing.展开更多
The effects of tempering holding time at 700℃on the morphology,mechanical properties,and behavior of nanoparticles in Ti-Mo ferritic steel with different Mo contents were analyzed using scanning electron microscopy a...The effects of tempering holding time at 700℃on the morphology,mechanical properties,and behavior of nanoparticles in Ti-Mo ferritic steel with different Mo contents were analyzed using scanning electron microscopy and transmission electron microscopy.The equilibrium solid solution amounts of Mo,Ti,and C in ferritic steel at various temperatures were calculated,and changes in the sizes of nanoparticles over time at different Mo contents were analyzed.The experimental results and theoretical calculations were in good agreement with each other and showed that the size of nanoparticles in middle Mo content nano-ferrite(MNF)steel changed the least during aging.High Mo contents inhibited the maturation and growth of nanoparticles,but no obvious inhibitory effect was observed when the Mo content exceeded 0.37wt%.The tensile strength and yield strength continuously decreased with the tempering time.Analysis of the strengthening and toughening mechanisms showed that the different mechanical properties among the three different Mo content experiment steels were mainly determined by grain refinement strengthening(the difference range was 30-40 MPa)and precipitation strengthening(the difference range was 78-127 MPa).MNF steel displayed an ideal chemical ratio and the highest thermodynamic stability,whereas low Mo content nano-ferrite(LNF)steel and high Mo content nano-ferrite(HNF)steel displayed relatively similar thermodynamic stabilities.展开更多
Thin films of ternary compounds CuxInyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N,a material that decomposes below 300℃,and thus promises many interesting applications in...Thin films of ternary compounds CuxInyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N,a material that decomposes below 300℃,and thus promises many interesting applications in directwriting.The effect of In or Ti incorporation in altering the structure and physical properties of copper nitride was evaluated by characterizing the film structure,surface morphology,and temperature dependence of electrical resistivity.More Ti than In can be accommodated by copper nitride without completely deteriorating the Cu3N lattice.A small amount of In or Ti can improve the crystallinity,and consequently the surface morphology.While the decomposition temperature is rarely influenced by In,the Ti-doped sample,Cu59.31Ti2.64N38.05,shows an X-ray diffraction pattern dominated by characteristic Cu3N peaks,even after annealing at 500℃.Both In and Ti reduce the bandgap of the original Cu3N phase,resulting in a smaller electrical resistivity at room temperature.The samples with more Ti content manifest metal-semiconductor transition when cooled from room temperature down to 50 K.These results can be useful in improving the applicability of copper-nitride-based thin films.展开更多
Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal conductivity.Thin-layer hBNNSs were obtained...Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal conductivity.Thin-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).HBNNSs and ethylene-vinyl acetate copolymer(EVA)were introduced to HMX by a solvent-slurry process.For comparison,the HMX/EVA and HMX/EVA/graphene(HMX/EVA/G)composites were also prepared by a similar process.The morphology,crystal form,surface element distribution,thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively investigated.Results showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA,and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites,suggesting superior performance of desensitization of hBNNSs in explosives.展开更多
Based on the synchrotron soft X-ray absorption spectroscopy experiments,the fundamental electronic structures of layered Li NixCoyMnzO_(2)(NCM)are investigated systematically and the data of transitionmetal(TM)L-and O...Based on the synchrotron soft X-ray absorption spectroscopy experiments,the fundamental electronic structures of layered Li NixCoyMnzO_(2)(NCM)are investigated systematically and the data of transitionmetal(TM)L-and O K-edges spectra are collected.Distribution of Ni ions under different oxidation states is evaluated according to linear combination fit.It is found that the ratio of Ni^(4+)expands with the increase of Ni since it dominates in charge compensation during charging,and that the existence of Ni^(3+)is nearly negligible in delithiated NCM.The valence state of Co also strongly depends on Ni content,the perceptible position shift of Co L_(3)-edge absorption peak towards higher energy in Ni-rich material agrees well with the small voltage plateau at around 4.2 V.The stability of Mn is verified as no obvious spectral change with the Mn L-edge is observed.Moreover,as Ni content rises,the O 2p holes near the Femi level increases with higher oxidation state of Ni,indicating the enhanced hybridization of O 2p-TM 3 d.Delithiated NCMs with higher Ni content are prior to lose electron existing in highly hybridized Ni3 dO 2 p bands upon heating,which accounts for the pronounced O_(2)release in phase transitions and the deterioration in thermal stability.These detailed observation of the electronic structure evolution is one of the key ingredients to improving the electrochemical and thermal performance of NCM.展开更多
Commercial paper is of great potential as a ready-made substrate to make battery separator due to superior electrolyte affinity of cellulose.Nevertheless,the direct utilization of commercial paper as a separator is im...Commercial paper is of great potential as a ready-made substrate to make battery separator due to superior electrolyte affinity of cellulose.Nevertheless,the direct utilization of commercial paper as a separator is impracticable because of its micro-sized holes between coarse cellulose fibers,which might induce short circuits.Herein,a novel reinforced composite separator is proposed by modifying commercial paper(CP)with highdielectric polymer poly(vinylidene fluoride)(PVDF)via a vacuum filtration method.The paper substrate enables excellent electrolyte wettability and high ionic conductivity of the CP-PVDF composite separator due to the superior electrolyte affinity of cellulose molecule.Meanwhile,the strong hydrogen bonds between F atoms in PVDF and H atoms in the-OH groups of cellulose endow the separator with high thermal stability and mechanical strength.Moreover,the CP-PVDF exhibits outstanding interfacial compatibility toward Li metal anode and guarantees the prominent cycle durability of symmetric Li/Li cells up to 600 h.As a result,the LiFePO_(4)/Li cells assembled with CP-PVDF separator show dramatic rate performance with high discharge capacity of 113.7 m Ah g^(-1),and prolonged cycle life at 5 C.This work indicates that the paper-based composite membranes possess great potential for high-safety and electrochemical performance batteries.展开更多
Functional composite films were successfully prepared from cellulose, graphite(GP), and polyaniline(PANI) using a combination of physical and chemical processes. Cellulosewasdissolved in N-methylmorpholine-N-oxide mon...Functional composite films were successfully prepared from cellulose, graphite(GP), and polyaniline(PANI) using a combination of physical and chemical processes. Cellulosewasdissolved in N-methylmorpholine-N-oxide monohydrate(NMMO) and regenerated in water to form the matrix. GP was dispersed in the NMMO solvent prior to the dissolution of the cellulose, and PANI was deposited on the surfaces of the cellulose/GP films by in situ chemical polymerization. The structures of the PANI/cellusose/GP composite films were investigated using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy(SEM), and SEM/energy-dispersive X-ray spectroscopy. The mechanical strengths, thermal stabilities, conductivities, and antibacterial activities of the films were studied in detail. The results showed that GP formed a multilayered structure in the cellulose matrix and that the PANI nanoparticles were tightly wrapped on the film surface. The film thickness increased from 40 mm to 100 mm after the addition of GP and PANI. The tensile strength of the composite films was 80~107 MPa, with the elongation at break being 3%~10%. The final residual weight of the composite films was as high as 65%, and the conductivity of the composite films reached 14.36 S/m. The cellulose matrix ensured that the films were flexible and exhibited desirable mechanical properties, while the GP filler significantly improved the thermal stability of the films. The PANI coating acted as a protective layer during burning and provided good electrical conductivity and antibacterial activity against Escherichia coli; both of these characteristics were slightly enhanced by the incorporation of GP. These PANI/cellulose/GP composite films should be suitable for use in electronics, antistatic packing, and numerous other applications.展开更多
A new amorphous Al87.3Fe4.3V0.7Si1.7Mm6.0(Mm: misch metal) was prepared by using melt-spinning technique. Differential scanning calorimetry (DSC), X-ray diffraction (XRD). transmis-sion electron microscopy (TEM) and e...A new amorphous Al87.3Fe4.3V0.7Si1.7Mm6.0(Mm: misch metal) was prepared by using melt-spinning technique. Differential scanning calorimetry (DSC), X-ray diffraction (XRD). transmis-sion electron microscopy (TEM) and energy dispersive X-ray (EDX) have been used to investigatethe crystallization behaviour of thi5 amorphous alloy It is found that the crystallization processcan be concluded as follows: amorphous→ amorphous plus fcc-Al→ fcc-Al plus AI11(La,Ce)3plus i-phase (icosahedral)→ fcc-Al plus Al11(La,Ce)3 plus i-phase plus ic-phase (icosahedralcompounds). The results of microhardness measurement show that HV values are higher thanthose in Al-Fe-V-Si based alloy and the maximum HV value corresponds to the coexisting ofnanoscale Al particles and i-phase.展开更多
The formation and the thermal stability of a connected hard skeleton structure(CHSS) in the matrix of Mg-5Al-2Sn-5Ca(ATX525) alloy were investigated by using X-ray diffractometer, scanning electron microscopy, differe...The formation and the thermal stability of a connected hard skeleton structure(CHSS) in the matrix of Mg-5Al-2Sn-5Ca(ATX525) alloy were investigated by using X-ray diffractometer, scanning electron microscopy, differential scanning calorimeter, creep tester and isothermal treatment method. The results indicated that the CHSS composed of Mg2(Al,Ca) and Al2 Ca intermetallics was formed into a typical eutectic structure and no obvious change occurred when the samples were isothermally treated at 250 °C for 96 h and 350 °C for 72 h, respectively. It became a chained structure when isothermally treated at 450 °C for 48 h. The dissolution and reconstruction processes, however, were observed for the CHSS when the processing temperature was up to 550 °C. The creep life at the stress-temperature condition of 50MPa/200°C for the alloy treated at 450 °C for 48 h was as high as 510 h, and the strain at creep time of 100 h was as low as 0.03%, which indicated that the present alloy has not only a good thermal stability, but also a better heat resistance.展开更多
Ge-Ga-S thin films were deposited by magnetron sputtering with mean coordination number(MCN)ranging from 2.46 to 2.94.The physical properties of the Ge-Ga-S films,including optical band gap,refractive index,and thickn...Ge-Ga-S thin films were deposited by magnetron sputtering with mean coordination number(MCN)ranging from 2.46 to 2.94.The physical properties of the Ge-Ga-S films,including optical band gap,refractive index,and thickness,vary with the time of heat treatment.Based on the analysis of the topology model,it is concluded that the Ge-Ga-S thin films with components close to the stoichiometric ratio can form the most Ga-S bonds and Ga-S bonds,and the physical properties of the Ge27.3Ga6.3S66.3(MCN=2.62)film are the most stable.This is an important reference for thin film photonic devices.展开更多
Acetate-based imidazolium ionic liquids(ILs)are of great importance and widely applied in biomass processing and engineering but under stability issue due to the structure self–rearrangement induced by C2–H deproton...Acetate-based imidazolium ionic liquids(ILs)are of great importance and widely applied in biomass processing and engineering but under stability issue due to the structure self–rearrangement induced by C2–H deprotonation,by which the IL based biomass processing will be challenging.Herein,we demonstrated that the thermal stability of normal acetate-based imidazolim[C8C1Im][OAc]could be significantly improved by changing its cation and anion environment with the presence of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide IL([C4C1Im][NTf2]).When the molar fraction of[C8C1Im][OAc]was 0.3,the thermal stability of[C8C1Im][OAc]could be significantly improved(ΔT5%dec=+43°C).Detailed information obtained from thermal gravimetric analysis(TGA)and nuclear magnetic resonance(NMR)revealed that the addition of[C4C1 Im][NTf2]played a significant role in enhancing the thermal stability of[C8C1Im][OAc].It was proposed that the formation of an anion–π+structure network between[C8C1 Im][OAc]and[C4C1Im][NTf2]via strong hydrogen bond interactions greatly affects the environment of hydrogen atom in the imidazolium ring of each IL.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 61774169)the Natural Science Foundation of Hunan Province (No. 2022JJ30757)the Guangdong Science and Technology Planning Project (No.2018B030323010)。
文摘Thermal stability of perovskite materials is an issue impairing the long-term operation of inverted perovskite solar cells(PSCs). Herein, the thermal attenuation mechanism of the MAPb I3films that deposited on two different hole transport layers(HTL), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS) and poly(3,4-ethylenedioxythiophene)(PEDOT), is comprehensively studied by applying a heat treatment at 85℃. The thermal stress causes the mutual ions migration of I, Pb and Ag through the device, which leads to the thermal decomposition of perovskite to form Pb I2. Interestingly, we find that I ions tend to migrate more towards electron transport layer(ETL) during heating, which is different with the observation of I ions migration towards HTL when bias pressure is applied. Moreover, the use of electrochemical deposited PEDOT as HTL significantly decreases the defect density of MAPb I3films as compared to PEDOT:PSS supported one. The electrochemical deposition PEDOT has good carrier mobility and low acidity, which avoids the drawbacks of aqueous PEDOT:PSS. Accordingly, the inverted PSCs based on PEDOT show superior durability than that with PEDOT:PSS. Our results reveal detailed degradation routes of a new kind of inverted PSCs which can contribute to the understanding of the failure of thermal-aged inverted PSCs.
基金supported by National Natural Science Foundation of China (No.U21A2047 and 51971076)China Postdoctoral Science Foundation (Grant No.2019M653599)Guangdong Basic and Applied Basic Research Foundation (No.2019A1515110289)。
文摘A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr(wt.%) alloy is processed by solution treatment and high pressure torsion(HPT) at room temperature to produce a nanostructured light material with high hardness. The stability of this alloy is subsequently tested through isochronal annealing for 0.5 h at 373 K to 673 K. The results reveal a thermal stability that is vastly superior to that of conventional Mg-based alloys processed by severe plastic deformation: the grain size remains at around 50 nm on heating to 573 K, and as the temperature is increased to 673 K,grain growth is restricted to within 500 nm. The stability of grain refinement of the present alloy/processing combination allowing grain size to be limited to 55 nm after exposure at 573 K, appears to be nearly one order of magnitude better than for the other SPD processed Mg-RE type alloys, and 2 orders of magnitude better than those of SPD processed RE-free Mg alloys. This superior thermal stability is attributed to formation of co-clusters near and segregation at grain boundaries, which cause a thermodynamic stabilization of grain size, as well as formation of β-Mg_(5)RE equilibrium phase at grain boundaries, which impede grain growth by the Zener pinning effect. The hardness of the nanostructured Mg-Gd-Y-Zn-Zr alloy increases with increasing annealing temperature up to 573 K, which is quite different from the other SPD-processed Mg-based alloys. The high hardness of 136 HV after annealing at 573 K is mainly due to solute segregation and solute clustering at or near grain boundaries.
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research (No.2019B030302007)National Key Research and Development Program of China (No. 2019YFA0705900) funded by MOSTthe financial support by State Key Lab of Luminescent Materials and Devices,South China University of Technology (Skllmd-2022-03)。
文摘Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells(all-PSCs). To overcome this obstacle, the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1. The film morphology can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer. Detailed morphology investigations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends. Consequently, the optimized all-PSCs delivered an enhanced power conversion efficiency(PCE) of 15.21%along with improved carrier extraction and suppressed charge recombination. More importantly, the optimized all-PSCs remain over 90% of their initial PCEs under continuous thermal stress at 65 °C for over 500 h. This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.
基金funded by the National Natural Science Foundation of China (No.42261028,No.41961010,No.41801033)the "Light of West China" Program for the Organization Department of the Central Committee of the CPC, etc. (Zhang Mingli)+2 种基金the Chinese Academy of Sciences "Light of West China" Program for Western Young ScholarsIndustrial support program of higher education of Gansu province (2020C-40)Basic Research Innovation Group of Gansu province (20JR5RA478)
文摘The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy balance and the energy-water transfer within soils. To clarify the thermal-moisture dynamics and thermal stability of the active layer in permafrost regions under wet/dry conditions, the verified water-vapour-heat coupling model was used. Changes in the surface energy balance, energy-water transfer within the soil, and thickness of the active layer were quantitatively analyzed. The results demonstrate that rainfall changes significantly affect the Bowen ratio, which in turn affects surface energy exchange. Under wet/dry conditions, there is a positive correlation between rainfall and liquid water flux under the hydraulic gradient;water vapour migration is the main form under the temperature gradient, which indicates that the influence of water vapour migration on thermalmoisture dynamics of the active layer cannot be neglected. Concurrently, regardless of wet or dry conditions,disturbance of the heat transport by conduction caused by rainfall is stronger than that of convection by liquid water. In addition, when rainfall decreases by 1.5 times(212 mm) and increases by 1.5 times(477 mm), the thickness of the active layer increases by 0.12 m and decreases by 0.21 m, respectively. The results show that dry conditions are not conducive to the preservation of frozen soil;however, wet conditions are conducive to the preservation of frozen soil, although there is a threshold value. When this threshold value is exceeded, rainfall is unfavourable for the development of frozen soil.
基金funded by the Macao Foundation,the pre-research project of Civil Aerospace Technologies(Nos.D020308 and D020303)which is funded by the China National Space Administrationthe opening fund of the State Key Laboratory of Lunar and Planetary Sciences(Macao University of Science and Technology,Macao FDCT[Science and Technology Development Fund]No.119/2017/A3)。
文摘Macao Science Satellite-1(known as MSS-1)is a low-inclination mission that will be launched at the beginning of 2023.An optical bench is used for accessing high-precision strength and direction measurements of the magnetic field.In this paper,we present a thermal stability design for the optical bench based on quasi-kinematic support by kinematic hinges on the MSS-1.The change in angles with the finite element method(FEM)model modified by thermal deformation test data is analyzed.The robustness of the structure is also investigated via the Monte Carlo method.Two main results are obtained.First,the peak-to-peak value(Vp-p)of the inter-boresight angle is at most 1.24″,and the Vp-p of the inter-boresight angle modification and analysis is no more than 3.13″,both of which are better than those on the Swarm satellites in orbit.Second,the 90°fibers of the carbon-reinforced arm need to be strictly controlled during the technological process.
基金financial supports from the Project of the National Natural Science Foundation of China(22178304,22108239)the Start-up Funding of Ningbo Research Institute of Zhejiang University(20201207Z0204).
文摘A set of hydrodynamic similarity laws is applied to the scale-up of ethylene polymerization fluidized bed reactors(FBRs)under the condensed mode operation.The thermal stability of open-loop controlled FBRs is investigated by the homotopy continuation method.And the Hopf bifurcation point is selected as an index of the thermal stability similarity.The simulation results show the similarity in state variables,operation parameters,the space-time yield(STY),and the thermal stability of FBRs with different scales.Furthermore,the thermal stability behaviors and similarity of the closed-loop controlled FBRs with different scales are analyzed.The observed similar trend of Hopf bifurcation curves reveals the similarity in the thermal stability of closed-loop controlled FBRs with different scaling ratios.In general,the results of the thermal stability similarity confirm that the hydrodynamics scaling laws proposed in the work are applicable to the scale-up of FBRs under the condensed mode operation.
基金the Natural Science Foundation of Hunan Province (No. 07JJ3117)the Chinese Postdoctoral Science Foundation (No. 20070410303)the High Technology Research and Development Program of Hunan Province, China (No. 06FJ2007).
文摘This paper studies the effect of Ce on the thermal stability of the Ω phase in an Al-Cu-Mg-Ag alloy by TEM and tensile testing. It has been shown that Ce substantially increases the nucleation density of the Ω phase by acting as the heterogeneous nucleation center. Most impor-tantly,Ce improves the thermal stability of the Ω phase by decreasing the diffusion velocity of Cu atoms and increasing the energy barrier of the thickening ledge nucleation,thus improving the strength of the Al-Cu-Mg-Ag alloy at both room-and elevated-temperatures.
基金Project supported by the Ministry of Science and Technology of China(Grant Nos.2014DFB50130 and 2011CB612304)the National Natural Science Foundation of China(Grant Nos.51172168 and 51072139)
文摘To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy_(80)Ga_(20)(at.%) powder.The coercivity of the magnets increased from the undoped value of 12.72 kOe to a doped value of 21.44 kOe.A micro-structural analysis indicates that a well-developed core-shell structure forms in the magnets doped with Dy_(80)Ga_(20) powder.The improvement in magnetic properties is believed to be related to the refined and uniform matrix grains,continuous grain boundaries,and a hardened(Nd,Dy)_2Fe_(14)B shell surrounding the matrix grains.Additionally,the doped magnets exhibit an obvious improvement in thermal stability.For the magnets with added Dy_(80)Ga_(20) powder,the temperature coefficients of remanence(α) and coercivity(β) increased to-0.106%℃^(-1) and-0.60%℃^(-1) over the range 20-100 ℃,compared to temperature coefficients of-0.117%℃^(-1)(α) and-0.74%℃^(-1)(β) in the regular magnets without Dy_(80)Ga_(20) powder.The irreversible loss of magnetic flux(Hirr) was investigated at different temperatures.After being exposed to 150 ℃ for 2 h,the Hirr of magnets with 4 wt.%Dy_(80)Ga_(20) decreased by ~95%compared to that of the undoped magnets.The enhanced temperature coefficients and Hirr indicate improved thermal stability in the doped Nd-Fe-B magnets.The intergranular addition of Dy_(80)Ga_(20) also improved the corrosion resistance of the magnets because of the enhanced intergranular phase.In a corrosive atmosphere for 96 h,the mass loss of the sintered magnets with 4 wt.%Dy_(80)Ga_(20) was 2.68 mg/cm^2,less than 10%of that suffered by the undoped magnets(28.1 mg/cm^2).
基金Project supported by the Natural Science Foundation of Hunan Province (No. 05JJ30016), Foundation of Education Committee of Hunan Province (05C001), Foundation of Hengyang Sci. & Tech. Bureau (2005Cg10-23) and Fund for Distinguished Young Cadreman of Hengyang Normal University(2006)
文摘A one-dimensional chain cobalt(II) coordination polymer with 2,4,6-trimethyl- benzoic acid, 4,4-bipyridine and cobalt perchlorate anhydrous has been synthesized and charac- terized in the mixture solvent of water and alcohol. Crystal data for this complex: monoclinic, space group C2/c, a = 2.3805(8), b = 1.1464(4), c = 1.5807(5) nm, γ = 128.435(4)o, V = 3.3791(18) nm3, Dc = 1.246 g/cm3, Z = 4, F(000) = 1340, final GooF = 1.009, R = 0.0504 and wR = 0.1287. Structural analysis shows that the cobalt ion is coordinated with two nitrogen atoms of one 4,4- bipyridine molecule and four oxygen atoms from two 2,4,6-trimethylbenzoic acid molecules and two alcohol molecules, giving a distorted octahedral coordination geometry. The result of TG analysis indicates that the title complex is stable till 200 ℃.
基金The current study is co-supported by National Natural Science Foundation of China(51871032,51901202)Fundamental Research Funds for the Central Universities(2019CDQYCL032)Chongqing+2 种基金111 Project by the Ministry of Education(B16007)Graduate research and innovation foundation of Chongqing,China(Grant No.CYB17004)Natural Science Foundation of Jiangsu Province(No.BK20160958).
文摘Grain growth can modify the texture orientation and the fraction of different texture component.The thermal stability of two texture component in an extruded magnesium AZ31 alloy was investigated.Three types samples with different texture distribution were prepared.The results show that normal grain growth takes place in the magnesium AZ31 alloy during annealing at 300℃ and 450℃.But the grain growth does not lead to the strengthening of either texture component.Both the<0002>⊥ED texture and<0002>//ED texture components show good thermal stability,without influence of the texture volume fraction.The two different texture component possess comparable boundary migration ability,so grains of the two texture component consume indifferently the other grains,or are equally consumed during annealing.
基金the National Natural Science Foundation of China(No.51601174).
文摘The effects of tempering holding time at 700℃on the morphology,mechanical properties,and behavior of nanoparticles in Ti-Mo ferritic steel with different Mo contents were analyzed using scanning electron microscopy and transmission electron microscopy.The equilibrium solid solution amounts of Mo,Ti,and C in ferritic steel at various temperatures were calculated,and changes in the sizes of nanoparticles over time at different Mo contents were analyzed.The experimental results and theoretical calculations were in good agreement with each other and showed that the size of nanoparticles in middle Mo content nano-ferrite(MNF)steel changed the least during aging.High Mo contents inhibited the maturation and growth of nanoparticles,but no obvious inhibitory effect was observed when the Mo content exceeded 0.37wt%.The tensile strength and yield strength continuously decreased with the tempering time.Analysis of the strengthening and toughening mechanisms showed that the different mechanical properties among the three different Mo content experiment steels were mainly determined by grain refinement strengthening(the difference range was 30-40 MPa)and precipitation strengthening(the difference range was 78-127 MPa).MNF steel displayed an ideal chemical ratio and the highest thermodynamic stability,whereas low Mo content nano-ferrite(LNF)steel and high Mo content nano-ferrite(HNF)steel displayed relatively similar thermodynamic stabilities.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51172272,10904165,and 11290161)the National Basic Research Program of China (Grant No. 2012CB933002)
文摘Thin films of ternary compounds CuxInyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N,a material that decomposes below 300℃,and thus promises many interesting applications in directwriting.The effect of In or Ti incorporation in altering the structure and physical properties of copper nitride was evaluated by characterizing the film structure,surface morphology,and temperature dependence of electrical resistivity.More Ti than In can be accommodated by copper nitride without completely deteriorating the Cu3N lattice.A small amount of In or Ti can improve the crystallinity,and consequently the surface morphology.While the decomposition temperature is rarely influenced by In,the Ti-doped sample,Cu59.31Ti2.64N38.05,shows an X-ray diffraction pattern dominated by characteristic Cu3N peaks,even after annealing at 500℃.Both In and Ti reduce the bandgap of the original Cu3N phase,resulting in a smaller electrical resistivity at room temperature.The samples with more Ti content manifest metal-semiconductor transition when cooled from room temperature down to 50 K.These results can be useful in improving the applicability of copper-nitride-based thin films.
基金The project was supported by Equipment Pre-research Key Laboratory Fund(No.6142020305)The authors would like to thank Shiyanjia Lab(www.shiyanjia.com)for the support of XPS test.
文摘Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal conductivity.Thin-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).HBNNSs and ethylene-vinyl acetate copolymer(EVA)were introduced to HMX by a solvent-slurry process.For comparison,the HMX/EVA and HMX/EVA/graphene(HMX/EVA/G)composites were also prepared by a similar process.The morphology,crystal form,surface element distribution,thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively investigated.Results showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA,and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites,suggesting superior performance of desensitization of hBNNSs in explosives.
基金supported by the National Natural Science Foundation of China(No.51976209)the Fundamental Research Funds for the Central Universities(No.WK2320000040)supported by the Youth Innovation Promotion Association CAS(No.Y201768)。
文摘Based on the synchrotron soft X-ray absorption spectroscopy experiments,the fundamental electronic structures of layered Li NixCoyMnzO_(2)(NCM)are investigated systematically and the data of transitionmetal(TM)L-and O K-edges spectra are collected.Distribution of Ni ions under different oxidation states is evaluated according to linear combination fit.It is found that the ratio of Ni^(4+)expands with the increase of Ni since it dominates in charge compensation during charging,and that the existence of Ni^(3+)is nearly negligible in delithiated NCM.The valence state of Co also strongly depends on Ni content,the perceptible position shift of Co L_(3)-edge absorption peak towards higher energy in Ni-rich material agrees well with the small voltage plateau at around 4.2 V.The stability of Mn is verified as no obvious spectral change with the Mn L-edge is observed.Moreover,as Ni content rises,the O 2p holes near the Femi level increases with higher oxidation state of Ni,indicating the enhanced hybridization of O 2p-TM 3 d.Delithiated NCMs with higher Ni content are prior to lose electron existing in highly hybridized Ni3 dO 2 p bands upon heating,which accounts for the pronounced O_(2)release in phase transitions and the deterioration in thermal stability.These detailed observation of the electronic structure evolution is one of the key ingredients to improving the electrochemical and thermal performance of NCM.
基金financially supported by the National Natural Science Foundation of China(21863006,51662029)Key Laboratory of Jiangxi Province for Environment and Energy Catalysis(20181BCD40004)
文摘Commercial paper is of great potential as a ready-made substrate to make battery separator due to superior electrolyte affinity of cellulose.Nevertheless,the direct utilization of commercial paper as a separator is impracticable because of its micro-sized holes between coarse cellulose fibers,which might induce short circuits.Herein,a novel reinforced composite separator is proposed by modifying commercial paper(CP)with highdielectric polymer poly(vinylidene fluoride)(PVDF)via a vacuum filtration method.The paper substrate enables excellent electrolyte wettability and high ionic conductivity of the CP-PVDF composite separator due to the superior electrolyte affinity of cellulose molecule.Meanwhile,the strong hydrogen bonds between F atoms in PVDF and H atoms in the-OH groups of cellulose endow the separator with high thermal stability and mechanical strength.Moreover,the CP-PVDF exhibits outstanding interfacial compatibility toward Li metal anode and guarantees the prominent cycle durability of symmetric Li/Li cells up to 600 h.As a result,the LiFePO_(4)/Li cells assembled with CP-PVDF separator show dramatic rate performance with high discharge capacity of 113.7 m Ah g^(-1),and prolonged cycle life at 5 C.This work indicates that the paper-based composite membranes possess great potential for high-safety and electrochemical performance batteries.
基金financial support from the International S&T Cooperation Program of China (No.2015DFG31860)the National Science Foundation of China for the Key Projects (Nos.31430092 and 31110103902)
文摘Functional composite films were successfully prepared from cellulose, graphite(GP), and polyaniline(PANI) using a combination of physical and chemical processes. Cellulosewasdissolved in N-methylmorpholine-N-oxide monohydrate(NMMO) and regenerated in water to form the matrix. GP was dispersed in the NMMO solvent prior to the dissolution of the cellulose, and PANI was deposited on the surfaces of the cellulose/GP films by in situ chemical polymerization. The structures of the PANI/cellusose/GP composite films were investigated using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy(SEM), and SEM/energy-dispersive X-ray spectroscopy. The mechanical strengths, thermal stabilities, conductivities, and antibacterial activities of the films were studied in detail. The results showed that GP formed a multilayered structure in the cellulose matrix and that the PANI nanoparticles were tightly wrapped on the film surface. The film thickness increased from 40 mm to 100 mm after the addition of GP and PANI. The tensile strength of the composite films was 80~107 MPa, with the elongation at break being 3%~10%. The final residual weight of the composite films was as high as 65%, and the conductivity of the composite films reached 14.36 S/m. The cellulose matrix ensured that the films were flexible and exhibited desirable mechanical properties, while the GP filler significantly improved the thermal stability of the films. The PANI coating acted as a protective layer during burning and provided good electrical conductivity and antibacterial activity against Escherichia coli; both of these characteristics were slightly enhanced by the incorporation of GP. These PANI/cellulose/GP composite films should be suitable for use in electronics, antistatic packing, and numerous other applications.
文摘A new amorphous Al87.3Fe4.3V0.7Si1.7Mm6.0(Mm: misch metal) was prepared by using melt-spinning technique. Differential scanning calorimetry (DSC), X-ray diffraction (XRD). transmis-sion electron microscopy (TEM) and energy dispersive X-ray (EDX) have been used to investigatethe crystallization behaviour of thi5 amorphous alloy It is found that the crystallization processcan be concluded as follows: amorphous→ amorphous plus fcc-Al→ fcc-Al plus AI11(La,Ce)3plus i-phase (icosahedral)→ fcc-Al plus Al11(La,Ce)3 plus i-phase plus ic-phase (icosahedralcompounds). The results of microhardness measurement show that HV values are higher thanthose in Al-Fe-V-Si based alloy and the maximum HV value corresponds to the coexisting ofnanoscale Al particles and i-phase.
文摘The formation and the thermal stability of a connected hard skeleton structure(CHSS) in the matrix of Mg-5Al-2Sn-5Ca(ATX525) alloy were investigated by using X-ray diffractometer, scanning electron microscopy, differential scanning calorimeter, creep tester and isothermal treatment method. The results indicated that the CHSS composed of Mg2(Al,Ca) and Al2 Ca intermetallics was formed into a typical eutectic structure and no obvious change occurred when the samples were isothermally treated at 250 °C for 96 h and 350 °C for 72 h, respectively. It became a chained structure when isothermally treated at 450 °C for 48 h. The dissolution and reconstruction processes, however, were observed for the CHSS when the processing temperature was up to 550 °C. The creep life at the stress-temperature condition of 50MPa/200°C for the alloy treated at 450 °C for 48 h was as high as 510 h, and the strain at creep time of 100 h was as low as 0.03%, which indicated that the present alloy has not only a good thermal stability, but also a better heat resistance.
基金the National Natural Science Foundation of China(Grant Nos.61675105,61775111,and 61904091)Ningbo Optoelectronic Materials and Devices Laboratory(Grant No.2009B21007)。
文摘Ge-Ga-S thin films were deposited by magnetron sputtering with mean coordination number(MCN)ranging from 2.46 to 2.94.The physical properties of the Ge-Ga-S films,including optical band gap,refractive index,and thickness,vary with the time of heat treatment.Based on the analysis of the topology model,it is concluded that the Ge-Ga-S thin films with components close to the stoichiometric ratio can form the most Ga-S bonds and Ga-S bonds,and the physical properties of the Ge27.3Ga6.3S66.3(MCN=2.62)film are the most stable.This is an important reference for thin film photonic devices.
基金financially supported by the National Natural Science Foundation of China(21776026)the Liaoning Revitalization Talents Program(XLYC1902037)the start-up research funding of Beijing Institute of Technology(3160011181808)。
文摘Acetate-based imidazolium ionic liquids(ILs)are of great importance and widely applied in biomass processing and engineering but under stability issue due to the structure self–rearrangement induced by C2–H deprotonation,by which the IL based biomass processing will be challenging.Herein,we demonstrated that the thermal stability of normal acetate-based imidazolim[C8C1Im][OAc]could be significantly improved by changing its cation and anion environment with the presence of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide IL([C4C1Im][NTf2]).When the molar fraction of[C8C1Im][OAc]was 0.3,the thermal stability of[C8C1Im][OAc]could be significantly improved(ΔT5%dec=+43°C).Detailed information obtained from thermal gravimetric analysis(TGA)and nuclear magnetic resonance(NMR)revealed that the addition of[C4C1 Im][NTf2]played a significant role in enhancing the thermal stability of[C8C1Im][OAc].It was proposed that the formation of an anion–π+structure network between[C8C1 Im][OAc]and[C4C1Im][NTf2]via strong hydrogen bond interactions greatly affects the environment of hydrogen atom in the imidazolium ring of each IL.
