All-solid-state batteries(ASSBs)have garnered significant interest as the next-generation in battery technology,praised for their superior safety and high energy density.However,a conductive agent accelerates the unde...All-solid-state batteries(ASSBs)have garnered significant interest as the next-generation in battery technology,praised for their superior safety and high energy density.However,a conductive agent accelerates the undesirable side reactions of sulfide-based solid electrolytes(SEs),resulting in poor electrochemical properties with increased interfacial resistance.Here,we propose a wet chemical method rationally designed to achieve a conformal coating of lithium-indium chloride(Li_(3)InCl_(6))onto vapor-grown carbon fibers(VGCFs)as conductive agents.First,with the advantage of the Li_(3)InCl_(6) protective layer,use of VGCF@Li_(3)InCl_(6) leads to enhanced interfacial stability and improved electrochemical properties,including stable cycle performance.These results indicate that the Li_(3)InCl_(6) protective layer suppresses the unwanted reaction between Li_(6)PS_(5)Cl(LPSCl)and VGCF.Second,VGCF@Li_(3)InCl_(6) effectively promotes polytetrafluoroethylene(PTFE)fibrillization,leading to a homogeneous electrode microstructure.The uniform distribution of the cathode active material(CAM)in the electrode results in reduced charge-transfer resistance(R_(ct))and enhanced Li-ion kinetics.As a result,a full cell with the LiNi_(x)Mn_(y)Co_(z)O_(2)(NCM)/VGCF@Li_(3)InCl_(6) electrode shows an areal capacity of 7.7mAhcm^(−2) at 0.05 C and long-term cycle stability of 77.9%over 400 cycles at 0.2 C.This study offers a strategy for utilizing stable carbon-based conductive agents in sulfide-based ASSBs to enhance their electrochemical performance.展开更多
In this study,the impact of morphology of conductive agent and anode material(Fe3O4)on lithium storage properties was throughly investigated.Granular and belt-like Fe3O4active materials were separately blended with tw...In this study,the impact of morphology of conductive agent and anode material(Fe3O4)on lithium storage properties was throughly investigated.Granular and belt-like Fe3O4active materials were separately blended with two kinds of conductive agents(i.e.,granular acetylene black and multi-walled carbon nanotube)as anodes in lithium-ion batteries(LIBs),respectively.It was found that the morphology of conductive agent is of utmost importance in determining LIBs storage properties.In contrast,not as the way we anticipated,the morphology of anode material merely plays a subordinate role in their electrochemical performances.Further,the morphology-matching principle of electrode materials was discussed so as to render their utilization more rational and effective in LIBs.展开更多
Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated us...Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.展开更多
We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β ...We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β = 1.33, which is independent of initial condition and mass rate. The present model can be viewed as the model composed by independent quasi-particles, the centre of energy. In this way, heat current can be calculated. Based on the theory of dynamic billiard, the divergent exponent of heat conductivity is estimated to be α = 0.33, which is confirmed by a simple numerical calculation.展开更多
Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines gi...Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges,such as prolonged lithium extraction periods,diminished lithium extraction efficiency,and considerable environmental pollution.In this work,Li FePO4(LFP)served as the electrode material for electrochemical lithium extraction.The conductive network in the LFP electrode was optimized by adjusting the type of conductive agent.This approach resulted in high lithium extraction efficiency and extended cycle life.When the single conductive agent of acetylene black(AB)or multiwalled carbon nanotubes(MWCNTs)was replaced with the mixed conductive agent of AB/MWCNTs,the average diffusion coefficient of Li+in the electrode increased from 2.35×10^(-9)or 1.77×10^(-9)to 4.21×10^(-9)cm^(2)·s^(-1).At the current density of 20 mA·g^(-1),the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent(AB)to 35.62 mg with the mixed conductive agent(AB/MWCNTs).When the mixed conductive agent was used,the capacity retention of the electrode after 30 cycles reached 82.9%,which was considerably higher than the capacity retention of 65.8%obtained when the single AB was utilized.Meanwhile,the electrode with mixed conductive agent of AB/MWCNTs provided good cycling performance.When the conductive agent content decreased or the loading capacity increased,the electrode containing the mixed conductive agent continued to show excellent electrochemical performance.Furthermore,a self-designed,highly efficient,continuous lithium extraction device was constructed.The electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this device.This work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes.展开更多
Nickel nitrate was introduced into carbon blocks by using ECA aggregates as catalyst-carrier.The Ni-containing anthracite aggregates were firstly prepared by mixing anthracite aggregates in nickel nitrate ethanol solu...Nickel nitrate was introduced into carbon blocks by using ECA aggregates as catalyst-carrier.The Ni-containing anthracite aggregates were firstly prepared by mixing anthracite aggregates in nickel nitrate ethanol solution and then incorporated into carbon blocks after pre-treating.The phase composition,microstructure and properties of all carbon blocks fired at 1 000℃or 1 400℃in a coke bed were studied with the aid of an X-ray diffractomer,a field emission scanning electron microscope,a mercury porosimetry and a laser thermal conductivity meter.The results showed that the addition of Ni-containing anthracite aggregates promoted the formation of one-dimensional nanocarbon andβ-SiC whiskers at 1 000℃and the growth ofβ-Sialon at 1 400℃,respectively.Moreover,the cold compressive strength and microporosity characteristics of the carbon blocks with the addition of Ni-containing anthracite aggregates were enhanced and the thermal conductivity was remarkably improved attributing to the high heat conductive network formed by the ceramic phases.展开更多
In order to solve the problem of poor conductivity of traditional LiFePO_(4)cathode binders,we developed sodium alginate-Congo red copolymers(SA-CR)as water-soluble electrically conductive and mechanically robust comp...In order to solve the problem of poor conductivity of traditional LiFePO_(4)cathode binders,we developed sodium alginate-Congo red copolymers(SA-CR)as water-soluble electrically conductive and mechanically robust composite binder.Unlike most other electrically conductive polymer binders,the procedure is straightforward and low-cost to prepare SA-CR binder.Various SA-CR copolymers were prepared with different degree of compounding of CR to investigate the effect of CR on the electrochemical and physical properties of the prepared electrodes.The copolymer whose composition was filled with a mixture of SA and CR at a 3:1 mass ratio showed the best cell performance,due to the well-balanced electrical conductivity and mechanical properties.It exhibited a specific capacity of 118.8 m Ah/g at the 100th cycle with 92.1%capacity retention,significantly better than the 108.5 m Ah/g of conventional acetylene black electrodes.CR as a conduction-promoting agent in water-soluble composite binder favors the formation of continuous and homogenous conducting bridges throughout the electrode and increases the compaction density of electrode by reducing the conducting agent content of acetylene black and thus the improvement of electrode performance is realized.展开更多
Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical pr...Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.展开更多
The hydration behaviors and expansive properties of MgO-type expansive agent curing at different temperatures and environment were investigated.When the curing temperatures changed from 25℃ to 50℃,the conductivities...The hydration behaviors and expansive properties of MgO-type expansive agent curing at different temperatures and environment were investigated.When the curing temperatures changed from 25℃ to 50℃,the conductivities of MgO samples increased from 40 to 80 μs/cm,and the hydrations of MgO were quickened up obviously.Through SEM observation,the hydration product of MgO cured at 50℃ for 28 day was about 2-3μm in length.The expansion of pastes with 5% of the MgO-type expansive agent was from 0.36% to 1.01% when the curing temperature changed from 25oC to 50℃.When 8% of the MgO-type expansive agent was added,the early shrinkage of concrete was reduced.The expansion ratio increased with the curing temperature,and the expansive cracking of concrete with MgO-type expansive agent might be decreased by blending fly ash.展开更多
This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different...This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different amounts of composite conductive agent which are com1=0.25%,com2=0.5%,com3=0.75%and com4=1%are selected as the conductive materials for LIB slurries.Meanwhile,to discriminate the individual impacts of CB and Gr,two distinct mass ratios of CB to Gr,namely,m'cB:m'cr=1:2 and m'c:m'Gr=2:1,are additionally chosen.Moreover,the influence of single conductive additive agent CB or Gr with the same amount as composite conductive agent on the network structure of the LIB slurry is also investigated.Furthermore,Electrochemical Impedance Spectroscopy(EIS),Scanning Electron Microscopy(SEM)and Raman experiments are performed to obtain the electrochemical,morphological and Raman characterizations of LIB slurry,respectively.After analyzing the experimental results,the main conclusion shows that the synergistic interaction between CB and Gr ensures a high-level conductive effciency because of minimizing the amount of the conductive agent and increasing the amount of LiCoO_(2) particles to the utmost degree,which has the potential to substantially elevating the energy density of LIB.展开更多
Sulfide-based all-solid-state batteries(ASSBs)exhibit unparalleled application value due to the high ionic conductivity and good processability of sulfide solid electrolytes(SSEs).Carbon-based conductive agents(CAs)are ...Sulfide-based all-solid-state batteries(ASSBs)exhibit unparalleled application value due to the high ionic conductivity and good processability of sulfide solid electrolytes(SSEs).Carbon-based conductive agents(CAs)are often used in the construction of electronic conductive networks to achieve rapid electron transfer.However,CAs accelerate the formation of decomposition products of SSEs,and their effects on sulfide-based ASSBs are not fully understood.Herein,the effect of CAs(super P,vaper-grown carbonfibers,and carbon nanotubes)on the performance of sulfide-based ASSBs is investigated under different cathode active materials mass loading(8 and 25 mg⋅cm^(-2)).The results show that under low mass loading,the side reaction between the CAs and the SSEs deteriorates the performance of the cell,while the charge transfer promotion caused by the addition of CAs is only manifested under high mass loading.Furthermore,the gradient design strategy(enrichment of CAs near the current collector side and depletion of CAs near the electrolyte side)is applied to maximize the benefits of CAs in electron transport and reduce the adverse effects of CAs.The charge carrier transport barrier inside the high mass loading electrode is significantly reduced through the regulation of electronic conductivity.Consequently,the optimized electrode achieves a high areal capacity of 5.6 mAh⋅cm^(-2)at high current density(1.25 mA⋅cm2,0.2℃)at 25℃with a capacity retention of 87.85%after 100 cycles.This work provides a promising way for the design of high-mass loading electrodes with practical application value.展开更多
Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional（1D） and twodimensional（2D） lattices where atoms are regularly connected and temperatures of atoms are homogeneous...Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional（1D） and twodimensional（2D） lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.展开更多
As one of the traditional curations of traditional chinese medicine,heat moxi-bustion is that to conduct the heat on the points,free and warm the channels and in-vigorate the circulation of blood.A variety of heat mox...As one of the traditional curations of traditional chinese medicine,heat moxi-bustion is that to conduct the heat on the points,free and warm the channels and in-vigorate the circulation of blood.A variety of heat moxibustion have been used formedical and health care,for example,burning mugwort,electric heating and in-farred ray heating.Some inconveniences such as safety and energy limit appear展开更多
基金supported by the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korean Government(MOTIE)(RS-2024-00417730,HRD Program for Industrial Innovation)supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program-Materials&Components Technology Development Program)(20024261),Development of thick film electrodes and cell manufacturing technology for a high-performance lithium iron phosphate battery with energy density of over 200 Wh/kg was funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘All-solid-state batteries(ASSBs)have garnered significant interest as the next-generation in battery technology,praised for their superior safety and high energy density.However,a conductive agent accelerates the undesirable side reactions of sulfide-based solid electrolytes(SEs),resulting in poor electrochemical properties with increased interfacial resistance.Here,we propose a wet chemical method rationally designed to achieve a conformal coating of lithium-indium chloride(Li_(3)InCl_(6))onto vapor-grown carbon fibers(VGCFs)as conductive agents.First,with the advantage of the Li_(3)InCl_(6) protective layer,use of VGCF@Li_(3)InCl_(6) leads to enhanced interfacial stability and improved electrochemical properties,including stable cycle performance.These results indicate that the Li_(3)InCl_(6) protective layer suppresses the unwanted reaction between Li_(6)PS_(5)Cl(LPSCl)and VGCF.Second,VGCF@Li_(3)InCl_(6) effectively promotes polytetrafluoroethylene(PTFE)fibrillization,leading to a homogeneous electrode microstructure.The uniform distribution of the cathode active material(CAM)in the electrode results in reduced charge-transfer resistance(R_(ct))and enhanced Li-ion kinetics.As a result,a full cell with the LiNi_(x)Mn_(y)Co_(z)O_(2)(NCM)/VGCF@Li_(3)InCl_(6) electrode shows an areal capacity of 7.7mAhcm^(−2) at 0.05 C and long-term cycle stability of 77.9%over 400 cycles at 0.2 C.This study offers a strategy for utilizing stable carbon-based conductive agents in sulfide-based ASSBs to enhance their electrochemical performance.
基金financial aid from the National Natural Science Foundation of China(NSFC No.51472133)
文摘In this study,the impact of morphology of conductive agent and anode material(Fe3O4)on lithium storage properties was throughly investigated.Granular and belt-like Fe3O4active materials were separately blended with two kinds of conductive agents(i.e.,granular acetylene black and multi-walled carbon nanotube)as anodes in lithium-ion batteries(LIBs),respectively.It was found that the morphology of conductive agent is of utmost importance in determining LIBs storage properties.In contrast,not as the way we anticipated,the morphology of anode material merely plays a subordinate role in their electrochemical performances.Further,the morphology-matching principle of electrode materials was discussed so as to render their utilization more rational and effective in LIBs.
基金supported by the National Key Research and Development Program of China,China(2019YFA0705102)the National Natural Science Foundation of China,China(22179144,22005332)。
文摘Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10605020)the Natural Science Foundation of Zhejiang Province of China (Grant No. Y605376.)
文摘We propose a new concept, the centre of energy, to study energy diffusion and heat conduction in a one-dimensional hard-point model. For the diatom model, we find an anomalous energy diffusion as （x2） - tβ with β = 1.33, which is independent of initial condition and mass rate. The present model can be viewed as the model composed by independent quasi-particles, the centre of energy. In this way, heat current can be calculated. Based on the theory of dynamic billiard, the divergent exponent of heat conductivity is estimated to be α = 0.33, which is confirmed by a simple numerical calculation.
基金financially supported by the National Natural Science Foundation of China(No.52072322)the Department of Science and Technology of Sichuan Province,China(Nos.23GJHZ0147,23ZDYF0262,2022YFG0294,and 2019-GH02-00052-HZ)。
文摘Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges,such as prolonged lithium extraction periods,diminished lithium extraction efficiency,and considerable environmental pollution.In this work,Li FePO4(LFP)served as the electrode material for electrochemical lithium extraction.The conductive network in the LFP electrode was optimized by adjusting the type of conductive agent.This approach resulted in high lithium extraction efficiency and extended cycle life.When the single conductive agent of acetylene black(AB)or multiwalled carbon nanotubes(MWCNTs)was replaced with the mixed conductive agent of AB/MWCNTs,the average diffusion coefficient of Li+in the electrode increased from 2.35×10^(-9)or 1.77×10^(-9)to 4.21×10^(-9)cm^(2)·s^(-1).At the current density of 20 mA·g^(-1),the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent(AB)to 35.62 mg with the mixed conductive agent(AB/MWCNTs).When the mixed conductive agent was used,the capacity retention of the electrode after 30 cycles reached 82.9%,which was considerably higher than the capacity retention of 65.8%obtained when the single AB was utilized.Meanwhile,the electrode with mixed conductive agent of AB/MWCNTs provided good cycling performance.When the conductive agent content decreased or the loading capacity increased,the electrode containing the mixed conductive agent continued to show excellent electrochemical performance.Furthermore,a self-designed,highly efficient,continuous lithium extraction device was constructed.The electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this device.This work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes.
基金financial support from the National Natural Science Foundation of China (51574186)
文摘Nickel nitrate was introduced into carbon blocks by using ECA aggregates as catalyst-carrier.The Ni-containing anthracite aggregates were firstly prepared by mixing anthracite aggregates in nickel nitrate ethanol solution and then incorporated into carbon blocks after pre-treating.The phase composition,microstructure and properties of all carbon blocks fired at 1 000℃or 1 400℃in a coke bed were studied with the aid of an X-ray diffractomer,a field emission scanning electron microscope,a mercury porosimetry and a laser thermal conductivity meter.The results showed that the addition of Ni-containing anthracite aggregates promoted the formation of one-dimensional nanocarbon andβ-SiC whiskers at 1 000℃and the growth ofβ-Sialon at 1 400℃,respectively.Moreover,the cold compressive strength and microporosity characteristics of the carbon blocks with the addition of Ni-containing anthracite aggregates were enhanced and the thermal conductivity was remarkably improved attributing to the high heat conductive network formed by the ceramic phases.
基金financial support by the National Key R&D Program of China(No.2022YFB2502000)National Natural Science Foundation of China(Nos.52225208,52002352,U21A20174 and 52071295)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2020R01002)。
文摘In order to solve the problem of poor conductivity of traditional LiFePO_(4)cathode binders,we developed sodium alginate-Congo red copolymers(SA-CR)as water-soluble electrically conductive and mechanically robust composite binder.Unlike most other electrically conductive polymer binders,the procedure is straightforward and low-cost to prepare SA-CR binder.Various SA-CR copolymers were prepared with different degree of compounding of CR to investigate the effect of CR on the electrochemical and physical properties of the prepared electrodes.The copolymer whose composition was filled with a mixture of SA and CR at a 3:1 mass ratio showed the best cell performance,due to the well-balanced electrical conductivity and mechanical properties.It exhibited a specific capacity of 118.8 m Ah/g at the 100th cycle with 92.1%capacity retention,significantly better than the 108.5 m Ah/g of conventional acetylene black electrodes.CR as a conduction-promoting agent in water-soluble composite binder favors the formation of continuous and homogenous conducting bridges throughout the electrode and increases the compaction density of electrode by reducing the conducting agent content of acetylene black and thus the improvement of electrode performance is realized.
基金Funded by Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022KJ100)National Natural Science Foundation of China(No.52172019)。
文摘Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.
基金Funded by the National Project of "863" (2009AA03Z508)XiBu Traffic Program (2009ZB01)
文摘The hydration behaviors and expansive properties of MgO-type expansive agent curing at different temperatures and environment were investigated.When the curing temperatures changed from 25℃ to 50℃,the conductivities of MgO samples increased from 40 to 80 μs/cm,and the hydrations of MgO were quickened up obviously.Through SEM observation,the hydration product of MgO cured at 50℃ for 28 day was about 2-3μm in length.The expansion of pastes with 5% of the MgO-type expansive agent was from 0.36% to 1.01% when the curing temperature changed from 25oC to 50℃.When 8% of the MgO-type expansive agent was added,the early shrinkage of concrete was reduced.The expansion ratio increased with the curing temperature,and the expansive cracking of concrete with MgO-type expansive agent might be decreased by blending fly ash.
基金support from National Natural Science Foundation of China(grant No.52006176)the Ministry of Education's“Chunhui Plan"Collaborative Research project(grant No.202200491)the Key Research and Development Project of Shaanxi Province(grant No.2022kw-18).
文摘This paper clarified the network structure of the lithium-ion battery(LIB)slurry under effects of composite conductive agent amount and carbon black(CB)to graphene(Gr)mass ratio(m'_(CB):m'_(Gr)).Four different amounts of composite conductive agent which are com1=0.25%,com2=0.5%,com3=0.75%and com4=1%are selected as the conductive materials for LIB slurries.Meanwhile,to discriminate the individual impacts of CB and Gr,two distinct mass ratios of CB to Gr,namely,m'cB:m'cr=1:2 and m'c:m'Gr=2:1,are additionally chosen.Moreover,the influence of single conductive additive agent CB or Gr with the same amount as composite conductive agent on the network structure of the LIB slurry is also investigated.Furthermore,Electrochemical Impedance Spectroscopy(EIS),Scanning Electron Microscopy(SEM)and Raman experiments are performed to obtain the electrochemical,morphological and Raman characterizations of LIB slurry,respectively.After analyzing the experimental results,the main conclusion shows that the synergistic interaction between CB and Gr ensures a high-level conductive effciency because of minimizing the amount of the conductive agent and increasing the amount of LiCoO_(2) particles to the utmost degree,which has the potential to substantially elevating the energy density of LIB.
基金supported by Hunan Provincial Science and Technology Department(No.2021JJ10058).
文摘Sulfide-based all-solid-state batteries(ASSBs)exhibit unparalleled application value due to the high ionic conductivity and good processability of sulfide solid electrolytes(SSEs).Carbon-based conductive agents(CAs)are often used in the construction of electronic conductive networks to achieve rapid electron transfer.However,CAs accelerate the formation of decomposition products of SSEs,and their effects on sulfide-based ASSBs are not fully understood.Herein,the effect of CAs(super P,vaper-grown carbonfibers,and carbon nanotubes)on the performance of sulfide-based ASSBs is investigated under different cathode active materials mass loading(8 and 25 mg⋅cm^(-2)).The results show that under low mass loading,the side reaction between the CAs and the SSEs deteriorates the performance of the cell,while the charge transfer promotion caused by the addition of CAs is only manifested under high mass loading.Furthermore,the gradient design strategy(enrichment of CAs near the current collector side and depletion of CAs near the electrolyte side)is applied to maximize the benefits of CAs in electron transport and reduce the adverse effects of CAs.The charge carrier transport barrier inside the high mass loading electrode is significantly reduced through the regulation of electronic conductivity.Consequently,the optimized electrode achieves a high areal capacity of 5.6 mAh⋅cm^(-2)at high current density(1.25 mA⋅cm2,0.2℃)at 25℃with a capacity retention of 87.85%after 100 cycles.This work provides a promising way for the design of high-mass loading electrodes with practical application value.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11135001 and 11375066)the National Basic Research Program of China(Grant No.2013CB834100)
文摘Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional（1D） and twodimensional（2D） lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.
文摘As one of the traditional curations of traditional chinese medicine,heat moxi-bustion is that to conduct the heat on the points,free and warm the channels and in-vigorate the circulation of blood.A variety of heat moxibustion have been used formedical and health care,for example,burning mugwort,electric heating and in-farred ray heating.Some inconveniences such as safety and energy limit appear
