Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte ...Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte engineering currently relies on conventional evaluation criteria of reducing coulombic consumption,which implicitly presume its equivalence to irreversible capacity loss and complicates battery development.We introduce the detrimental ratioρto quantify the fraction of parasitic species that permanently degrades active material.This metric is independent and crucially complements total coulombic consumption for accurate performance evaluation.We systematically investigate multiple electrolyte formulations using high-precision leakage current measurements,open-circuit-voltage experiments,and post-mortem characterizations.Although some electrolytes exhibit similarly low coulombic consumption,they diverge significantly in capacity retention andρ.Especially,dimethyl-carbonate-based localized-high concentration electrolyte can synergically achieve low coulombic consumption and detrimental ratioρduring calendar aging,owing to its chemically inert and structurally resilient solidelectrolyte interface with minimal isolated Si material.By contrast,increasing fluoroethylene carbonate(FEC)additive content suppresses electrolyte breakdown but suffers aggravated chemical degradation of more LixSi isolation for irreversible capacity loss with a risingρ.This study critically reveals that the chemistry-characteristic detrimental ratioρestablishes physically informed performance evaluation to pave the way for accelerating battery development.展开更多
Premature ovarian insufficiency(POI)is characterized by irreversible loss of ovarian function before 40 years of age and affects 3.7%of women worldwide(Golezar et al.,2019;Huang et al.,2021).Raised serum follicle-stim...Premature ovarian insufficiency(POI)is characterized by irreversible loss of ovarian function before 40 years of age and affects 3.7%of women worldwide(Golezar et al.,2019;Huang et al.,2021).Raised serum follicle-stimulating hormone(FSH)levels,menstrual disturbance,and estrogen deficiency are the main symptoms of POl(European Society for Human Reproduction et al.,2016).Besides infertility,patients have an increased risk of long-term complications due to the early deficiency of ovarian steroids,such as osteoporosis,cardiovascular disease,and metabolic disorders(lshizuka,2021).Due to the lack of biomarkers for prediction or early diagnosis,most patients are not diagnosed until the failure stage(serum levels of FSH above 25 IU/L and amenorrhea),missing opportunities for intervention.Therefore,developing sensitive biomarkers for diminished ovarian reserves is paramount for timely treatment to improve reproductive outcomes and prevent long-term complications.展开更多
On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze th...On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.展开更多
Based on the first and second laws of thermodynamics,the heat transfer and flow(thermohydraulic)characteristics of horizontal supercritical pressure CO_(2)(S-CO_(2))in a circular pipe under heating conditions were inv...Based on the first and second laws of thermodynamics,the heat transfer and flow(thermohydraulic)characteristics of horizontal supercritical pressure CO_(2)(S-CO_(2))in a circular pipe under heating conditions were investigated numerically.Heating flows in two different diameters(d)of 4 and 6 mm were simulated in pipes with pressures of 8 MPa,mass fluxes(G)of 300 and 400 kg/(m^(2)·s),and heat fluxes(q)of 50,75 and 100 kW/m^(2).In the d=4 mm pipe,the peak heat transfer coefficient(hb)was about 3 times higher than in the d=6 mm pipe,while the entropy production due to fluid friction in the 4 mm pipe was on average 1.1 times higher,and the entropy production due to heat transfer was on average about 67%lower.A 4 mm tube was employed to further evaluate the influence of the applied wall heat flux,the results demonstrated that the irreversibility due to heat transfer was on average more than 4 times higher when heat flux density was 100 kW/m^(2)than when the heat flux density was 50 kW/m^(2),while the peak of heat transfer coefficient increased by 1.4 times as q was decreased from 100 to 50 kW/m^(2).The effect of thermal acceleration was ignored,while the buoyancy effect resulted in secondary flow and significantly affected the flow and heat transfer features.The jet flows were found in the vicinity of the lower wall of the pipe,which made the two fields of velocity and temperature gradient more synergistic,leading to an enhancement in heat transfer in the vicinity of the upper wall.The aggravation of heat transfer resulted in high irreversibility of heat transfer in the cross-sectional area near the wall,while the local friction irreversibility was less affected by the buoyancy effect,and the distribution was uniform.The uneven distribution of thermophysical properties also confirmed that the enhanced heat transfer occurred near the wall area at the bottom of the pipe.展开更多
With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium ...With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.展开更多
Though oxygen defects are associated with deteriorated structures and aggravated cycling performance in traditional layered cathodes,the role of oxygen defects is still ambiguous in Li-rich layered oxides due to the i...Though oxygen defects are associated with deteriorated structures and aggravated cycling performance in traditional layered cathodes,the role of oxygen defects is still ambiguous in Li-rich layered oxides due to the involvement of oxygen redox.Herein,a Co-free Li-rich layered oxide Li_(1.286)Ni_(0.071)Mn_(0.643)O_(2)has been prepared by a co-precipitation method to systematically investigate the undefined effects of the oxygen defects.A significant O_(2)release and the propagation of oxygen vacancies were detected by operando differential electrochemical mass spectroscopy(DEMS)and electron energy loss spectroscopy(EELS),respectively.Scanning transmission electron microscopy-high angle annular dark field(STEMHAADF)reveals the oxygen vacancies fusing to nanovoids and monitors a stepwise electrochemical activation process of the large Li_(2)MnO_(3)domain upon cycling.Combined with the quantitative analysis conducted by the energy dispersive spectrometer(EDS),existed nano-scale oxygen defects actually expose more surface to the electrolyte for facilitating the electrochemical activation and subsequently increasing available capacity.Overall,this work persuasively elucidates the function of oxygen defects on oxygen redox in Co-free Li-rich layered oxides.展开更多
This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of...This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.展开更多
The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origi...The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process.In this study,focusing on Ah-level pouch cells for reliability,an ultrahigh initial Coulombic efficiency(96.1%)is achieved in an archetypical Li-rich layered oxide material.Combining the structure and electrochemistry analysis,we demonstrate that the achievement of high-capacity reversibility is a kinetic effect,primarily related to the sluggish Li mobility during oxygen reduction.Activating oxygen reduction through small density would induce the oxygen framework contraction,which,according to Pauli repulsion,imposes a great repulsive force to hinder the transport of tetrahedral Li.The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and,more importantly,contributes to 6%Coulombic efficiency enhancement as well as 10%energy density improvement for pouch cells,which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry.展开更多
Irreversible glacier mass loss has profound impacts on water resource regulation,climate change adaptation,ecosystem sustainability,and socioeconomic development,aligning closely with the 17 Sustainable Development Go...Irreversible glacier mass loss has profound impacts on water resource regulation,climate change adaptation,ecosystem sustainability,and socioeconomic development,aligning closely with the 17 Sustainable Development Goals set by the UN for2030.Moreover,the question“What would happen if all the ice on the planet melted?”展开更多
The supercritical carbon dioxide(sCO_(2))cycle can be powered by traditional as well as clean energy.To help users obtain more accurate results than the literatures with pre-set compressor efficiency,we proposed a com...The supercritical carbon dioxide(sCO_(2))cycle can be powered by traditional as well as clean energy.To help users obtain more accurate results than the literatures with pre-set compressor efficiency,we proposed a complete model to establish a link between the performance,sizes of compressors and parameters such as power W_(C),inlet temperature T_(in),inlet pressure P_(in)and pressure ratioε.Characteristic sizes of compressors l_(c),profile loss Y_(p)and clearance loss Ycl are all proportional to powers of W_(C)with powers of 0.5,-0.075 and-0.5 to 0 respectively;the scaling laws are constant in the range of capacities from 20 MW to 200 MW.The compressor isentropic efficiencyη_(tt)grows as the W_(C)increases,and the curves become gentle.Compressor efficiency improves over the full power range when the speed is changed from standard speed to the optimal speed;theη_(tt)curves turn soft as the n increase.As the P_(in)and T_(in)approach the critical point,theη_(tt)increase.Compressor efficiency follows a parabolic curve as theεincreases,this parabolic distribution results from the tradeoff between the change in losses and the pressure distribution of blades.Theη_(tt)versus P_(in),T_(in)andεrelations are similar at various capacities because of insignificant changes in the distribution of losses.Compressor efficiency maps facilitate the estimation of system performance,while scaling law for irreversible losses and characteristic lengths,along with constant criterion analyses,aid in comprehending the characteristics of compressors across various capacities.展开更多
Although research interest in aqueous metal-sulfur batteries(AMSs)has surged due to their intrinsic low cost and high capacity,the practical application of AMSs remains a considerable challenge because of the restrict...Although research interest in aqueous metal-sulfur batteries(AMSs)has surged due to their intrinsic low cost and high capacity,the practical application of AMSs remains a considerable challenge because of the restrictive cycling stability.To circumvent this issue,we propose an innovative and simple pre-copper strategy to realize a high-durability aqueous Cu-S battery.The precopper strategy can effectively promote a stable metal dissolution/deposition,compensate for charge carriers,and facilitate reaction kinetics during the subsequent process.As a result,the aqueous Cu-S battery when coupled with S-decorated porous Ti_(3)C_(2)(S-d-Ti_(3)C_(2))exhibits excellent electrochemical performance,delivering a highly reversible capacity of 1805.4 mAh·g^(-1)in the initial cycle at 0.8 A·g^(-1),impressive cycling stability with 90.2%capacity retention over 800 cycles,and ultralow polarization~0.08 V even at a high current density of 3.1 A·g^(-1).The findings obtained in this work could pave the way for the design of highperformance sulfur-based aqueous batteries,which fill the vacancy of the necessary metal anode,delivering merits in both cost and cycle life.展开更多
基金supported by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy(EERE),Vehicle Technologies Office(VTO)under the Silicon Consortium Seedling project received by Z.H.Coperated for the DOE Office of Science by UChicago Argonne,LLC,under Contract DE-AC02-06CH11357+2 种基金Pacific Northwest National Laboratory(PNNL)was supported by the U.S.DOE,Office of Advanced Research Projects Agency-Energy(ARPA-E)under the EVs4ALL Program with the contract number DE-AC05-76RL01830operated by Battelle for the DOE under Contract DE-AC0576RL01830performed at the Oak Ridge National Laboratory(GMV)and supported by U.S.DOE’s VTO under the Silicon Consortium Program received by G.M.V.and directed by Carine Steinway,Nicolas Eidson Thomas,Thomas Do。
文摘Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte engineering currently relies on conventional evaluation criteria of reducing coulombic consumption,which implicitly presume its equivalence to irreversible capacity loss and complicates battery development.We introduce the detrimental ratioρto quantify the fraction of parasitic species that permanently degrades active material.This metric is independent and crucially complements total coulombic consumption for accurate performance evaluation.We systematically investigate multiple electrolyte formulations using high-precision leakage current measurements,open-circuit-voltage experiments,and post-mortem characterizations.Although some electrolytes exhibit similarly low coulombic consumption,they diverge significantly in capacity retention andρ.Especially,dimethyl-carbonate-based localized-high concentration electrolyte can synergically achieve low coulombic consumption and detrimental ratioρduring calendar aging,owing to its chemically inert and structurally resilient solidelectrolyte interface with minimal isolated Si material.By contrast,increasing fluoroethylene carbonate(FEC)additive content suppresses electrolyte breakdown but suffers aggravated chemical degradation of more LixSi isolation for irreversible capacity loss with a risingρ.This study critically reveals that the chemistry-characteristic detrimental ratioρestablishes physically informed performance evaluation to pave the way for accelerating battery development.
基金supported by the National Key Research&Developmental Program of China(2022YFC2703800,2022YFC2703000)the National Natural Science Foundation of China(82125014,82371646,32070847)+1 种基金Basic Science Center Program of NSFC(31988101)the Natural Science Foundation of Shandong Province(ZR202105250005,ZR2022YQ69,tsqn202211371).
文摘Premature ovarian insufficiency(POI)is characterized by irreversible loss of ovarian function before 40 years of age and affects 3.7%of women worldwide(Golezar et al.,2019;Huang et al.,2021).Raised serum follicle-stimulating hormone(FSH)levels,menstrual disturbance,and estrogen deficiency are the main symptoms of POl(European Society for Human Reproduction et al.,2016).Besides infertility,patients have an increased risk of long-term complications due to the early deficiency of ovarian steroids,such as osteoporosis,cardiovascular disease,and metabolic disorders(lshizuka,2021).Due to the lack of biomarkers for prediction or early diagnosis,most patients are not diagnosed until the failure stage(serum levels of FSH above 25 IU/L and amenorrhea),missing opportunities for intervention.Therefore,developing sensitive biomarkers for diminished ovarian reserves is paramount for timely treatment to improve reproductive outcomes and prevent long-term complications.
文摘On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.
基金supported by the European Union’s Horizon 2020 Research and Innovation Programme Project(No.882628)(Guo,https://cinea.ec.europa.eu/programmes/horizon-europe_en)(acceseed on 08 October 2024),and the Fundamental Research Funds for the Central Universities(buctrc202406)(Guo,https://english.buct.edu.cn/)(accessed on 08 October 2024).
文摘Based on the first and second laws of thermodynamics,the heat transfer and flow(thermohydraulic)characteristics of horizontal supercritical pressure CO_(2)(S-CO_(2))in a circular pipe under heating conditions were investigated numerically.Heating flows in two different diameters(d)of 4 and 6 mm were simulated in pipes with pressures of 8 MPa,mass fluxes(G)of 300 and 400 kg/(m^(2)·s),and heat fluxes(q)of 50,75 and 100 kW/m^(2).In the d=4 mm pipe,the peak heat transfer coefficient(hb)was about 3 times higher than in the d=6 mm pipe,while the entropy production due to fluid friction in the 4 mm pipe was on average 1.1 times higher,and the entropy production due to heat transfer was on average about 67%lower.A 4 mm tube was employed to further evaluate the influence of the applied wall heat flux,the results demonstrated that the irreversibility due to heat transfer was on average more than 4 times higher when heat flux density was 100 kW/m^(2)than when the heat flux density was 50 kW/m^(2),while the peak of heat transfer coefficient increased by 1.4 times as q was decreased from 100 to 50 kW/m^(2).The effect of thermal acceleration was ignored,while the buoyancy effect resulted in secondary flow and significantly affected the flow and heat transfer features.The jet flows were found in the vicinity of the lower wall of the pipe,which made the two fields of velocity and temperature gradient more synergistic,leading to an enhancement in heat transfer in the vicinity of the upper wall.The aggravation of heat transfer resulted in high irreversibility of heat transfer in the cross-sectional area near the wall,while the local friction irreversibility was less affected by the buoyancy effect,and the distribution was uniform.The uneven distribution of thermophysical properties also confirmed that the enhanced heat transfer occurred near the wall area at the bottom of the pipe.
基金Soft Science Research Project of Guangdong Province,Grant/Award Number:2017B030301013Shenzhen Science and Technology Research Grant,Grant/Award Number:JCYJ20200109140416788。
文摘With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.
基金supported by the National Natural Science Foundation of China(52272253)the"Lingyan"Research and Development Plan of Zhejiang Province(2022C01071)+2 种基金the S&T Innovation 2025 Major Special Programme of Ningbo(2018B10081)the Natural Science Foundation of Ningbo(202003N4030)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022299)。
文摘Though oxygen defects are associated with deteriorated structures and aggravated cycling performance in traditional layered cathodes,the role of oxygen defects is still ambiguous in Li-rich layered oxides due to the involvement of oxygen redox.Herein,a Co-free Li-rich layered oxide Li_(1.286)Ni_(0.071)Mn_(0.643)O_(2)has been prepared by a co-precipitation method to systematically investigate the undefined effects of the oxygen defects.A significant O_(2)release and the propagation of oxygen vacancies were detected by operando differential electrochemical mass spectroscopy(DEMS)and electron energy loss spectroscopy(EELS),respectively.Scanning transmission electron microscopy-high angle annular dark field(STEMHAADF)reveals the oxygen vacancies fusing to nanovoids and monitors a stepwise electrochemical activation process of the large Li_(2)MnO_(3)domain upon cycling.Combined with the quantitative analysis conducted by the energy dispersive spectrometer(EDS),existed nano-scale oxygen defects actually expose more surface to the electrolyte for facilitating the electrochemical activation and subsequently increasing available capacity.Overall,this work persuasively elucidates the function of oxygen defects on oxygen redox in Co-free Li-rich layered oxides.
基金Project supported by the National Natural Science Foundation of China(51401028)
文摘This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.
基金financially supported by the National Natural Science Foundation of China(Grant No.52272253)“Lingyan”Research and Development Plan of Zhejiang Province(Grant No.2022C01071)+2 种基金Low Cost Cathode Material(Grant No.TC220H06P)the Natural Science Foundation of Ningbo(Grant No.202003N4030)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2022299)
文摘The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process.In this study,focusing on Ah-level pouch cells for reliability,an ultrahigh initial Coulombic efficiency(96.1%)is achieved in an archetypical Li-rich layered oxide material.Combining the structure and electrochemistry analysis,we demonstrate that the achievement of high-capacity reversibility is a kinetic effect,primarily related to the sluggish Li mobility during oxygen reduction.Activating oxygen reduction through small density would induce the oxygen framework contraction,which,according to Pauli repulsion,imposes a great repulsive force to hinder the transport of tetrahedral Li.The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and,more importantly,contributes to 6%Coulombic efficiency enhancement as well as 10%energy density improvement for pouch cells,which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry.
基金supported by the National Natural Science Foundation of China(42471165 and 42471157)Science Fund for Creative Research Groups of Gansu Province(23JRR567)the West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202306).
文摘Irreversible glacier mass loss has profound impacts on water resource regulation,climate change adaptation,ecosystem sustainability,and socioeconomic development,aligning closely with the 17 Sustainable Development Goals set by the UN for2030.Moreover,the question“What would happen if all the ice on the planet melted?”
基金supported by the Natural Science Foundation of China(52130608,51821004)。
文摘The supercritical carbon dioxide(sCO_(2))cycle can be powered by traditional as well as clean energy.To help users obtain more accurate results than the literatures with pre-set compressor efficiency,we proposed a complete model to establish a link between the performance,sizes of compressors and parameters such as power W_(C),inlet temperature T_(in),inlet pressure P_(in)and pressure ratioε.Characteristic sizes of compressors l_(c),profile loss Y_(p)and clearance loss Ycl are all proportional to powers of W_(C)with powers of 0.5,-0.075 and-0.5 to 0 respectively;the scaling laws are constant in the range of capacities from 20 MW to 200 MW.The compressor isentropic efficiencyη_(tt)grows as the W_(C)increases,and the curves become gentle.Compressor efficiency improves over the full power range when the speed is changed from standard speed to the optimal speed;theη_(tt)curves turn soft as the n increase.As the P_(in)and T_(in)approach the critical point,theη_(tt)increase.Compressor efficiency follows a parabolic curve as theεincreases,this parabolic distribution results from the tradeoff between the change in losses and the pressure distribution of blades.Theη_(tt)versus P_(in),T_(in)andεrelations are similar at various capacities because of insignificant changes in the distribution of losses.Compressor efficiency maps facilitate the estimation of system performance,while scaling law for irreversible losses and characteristic lengths,along with constant criterion analyses,aid in comprehending the characteristics of compressors across various capacities.
基金We appreciate support from the National Natural Science Foundation of China(Nos.22005315 and22179109)Central Universities Fundamental Research Funds(No.SWU-KR22002)Chongqing Natural Science Foundation(No.cstc2020jcyjzdxmX0010).
文摘Although research interest in aqueous metal-sulfur batteries(AMSs)has surged due to their intrinsic low cost and high capacity,the practical application of AMSs remains a considerable challenge because of the restrictive cycling stability.To circumvent this issue,we propose an innovative and simple pre-copper strategy to realize a high-durability aqueous Cu-S battery.The precopper strategy can effectively promote a stable metal dissolution/deposition,compensate for charge carriers,and facilitate reaction kinetics during the subsequent process.As a result,the aqueous Cu-S battery when coupled with S-decorated porous Ti_(3)C_(2)(S-d-Ti_(3)C_(2))exhibits excellent electrochemical performance,delivering a highly reversible capacity of 1805.4 mAh·g^(-1)in the initial cycle at 0.8 A·g^(-1),impressive cycling stability with 90.2%capacity retention over 800 cycles,and ultralow polarization~0.08 V even at a high current density of 3.1 A·g^(-1).The findings obtained in this work could pave the way for the design of highperformance sulfur-based aqueous batteries,which fill the vacancy of the necessary metal anode,delivering merits in both cost and cycle life.
