Silicon monoxide(SiO)is an attractive anode material for next-generation lithium-ion batteries for its ultra-high theoretical capacity of 2680 mAh g−1.The studies to date have been limited to electrodes with a rela-ti...Silicon monoxide(SiO)is an attractive anode material for next-generation lithium-ion batteries for its ultra-high theoretical capacity of 2680 mAh g−1.The studies to date have been limited to electrodes with a rela-tively low mass loading(<3.5 mg cm^(−2)),which has seriously restricted the areal capacity and its potential in practical devices.Maximizing areal capacity with such high-capacity materials is critical for capitalizing their potential in practi-cal technologies.Herein,we report a monolithic three-dimensional(3D)large-sheet holey gra-phene framework/SiO(LHGF/SiO)composite for high-mass-loading electrode.By specifically using large-sheet holey graphene building blocks,we construct LHGF with super-elasticity and exceptional mechanical robustness,which is essential for accommodating the large volume change of SiO and ensuring the structure integrity even at ultrahigh mass loading.Additionally,the 3D porous graphene network structure in LHGF ensures excellent electron and ion transport.By systematically tailoring microstructure design,we show the LHGF/SiO anode with a mass loading of 44 mg cm^(−2)delivers a high areal capacity of 35.4 mAh cm^(−2)at a current of 8.8 mA cm^(−2)and retains a capacity of 10.6 mAh cm^(−2)at 17.6 mA cm^(−2),greatly exceeding those of the state-of-the-art commercial or research devices.Furthermore,we show an LHGF/SiO anode with an ultra-high mass loading of 94 mg cm^(−2)delivers an unprecedented areal capacity up to 140.8 mAh cm^(−2).The achievement of such high areal capacities marks a critical step toward realizing the full potential of high-capacity alloy-type electrode materials in practical lithium-ion batteries.展开更多
The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to s...The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.展开更多
The growing demand for advanced electrochemical energy storage systems(EESSs)with high energy densities for electric vehicles and portable electronics is driving the electrode revolution,in which the development of hi...The growing demand for advanced electrochemical energy storage systems(EESSs)with high energy densities for electric vehicles and portable electronics is driving the electrode revolution,in which the development of high-mass-loading electrodes(HMLEs)is a promising route to improve the energy density of batteries packed in limited spaces through the optimal enlargement of active material loading ratios and reduction of inactive component ratios in overall cell devices.However,HMLEs face significant challenges including inferior charge kinetics,poor electrode structural stability,and complex and expensive production processes.Based on this,this review will provide a comprehensive summary of HMLEs,beginning with a basic presentation of factors influencing HMLE electrochemical properties,the understanding of which can guide optimal HMLE designs.Rational strategies to improve the electrochemical performance of HMLEs accompanied by corresponding advantages and bottlenecks are subsequently discussed in terms of various factors ranging from inactive component modification to active material design to structural engineering at the electrode scale.This review will also present the recent progress and approaches of HMLEs applied in various EESSs,including advanced secondary batteries(lithium-/sodium-/potassium-/aluminum-/calcium-ion batteries,lithium metal anodes,lithium-sulfur batteries,lithium-air batteries,zinc batteries,magnesium batteries)and supercapacitors.Finally,this review will examine the challenges and prospects of HMLE commercialization with a focus on thermal safety,performance evaluation,advanced characterization,and production cost assessment to guide future development.展开更多
As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most c...As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most cases,constructing three-dimensional(3D)graphene networks is widely utilized to promote the permeation of electrolyte and enhance the utilization of active materials.In this work,conventional freeze-drying process is utilized in the fabrication of G-MSCs to constitute 3D interconnected networks micro-electrodes,and further by regulating the composition of inks,carbon spheres(CSs)at different mass loadings are introduced into the graphene scaffolds to further increase the active sites of the micro-electrodes.The fabricated all carbon-based MSC with the optimal mass loading of CSs(0.406 mg cm^(-2))exhibits a high specific areal capacitance of 17.01mF cm^(-2)at the scan rate of 10mV s^(-1)and a capacitance retention of 93.14%after 10000 cycles at the scan rate of 500 mV s^(-1).The proposed microfabrication process is facile and fully compatible with modern microtechnologies and will be highly suitable for large-scale production and integration.展开更多
High areal capacity is one of the critically important points for potassium-ion batteries(PIBs)for practical applications,which relies on high areal-massloading electrodes operating at high reversible capacity.However...High areal capacity is one of the critically important points for potassium-ion batteries(PIBs)for practical applications,which relies on high areal-massloading electrodes operating at high reversible capacity.However,it is remarkably restricted by the mechanical instability and sluggish charge transfer induced by the increased mass loading.To overcome such challenge,we report the rationally designed bimetallic selenides CoSe2/SnSe2 heterostructures confined in hierarchical carbon nanofibers(CSSe@CNFs),which enables the electrodes robust mechanical stability,enhanced electron transport,and reduced ion-diffusion energy barrier for facilitating reaction kinetics.Accordingly,an impressive areal mass loading up to 25.3 mg cm^(−2)was achieved,which endowed a high areal capacity of 7.58 mAh cm^(−2)for such a free-standing electrode.This is stateof-the-art among the PIBs,exceeding that of today’s industry standard(∼3 mAh cm^(−2)for LIBs).Furthermore,it delivered long-term stability over 3700 cycles at high current density(∼2 mA cm^(−2),vs 1 mA cm^(−2)in LIBs).Moreover,the as-constructed full battery achieved a high energy density of 172.8 Wh kg-1 at 0.05 A g^(−1)with a satisfied cycle stability over 2000 cycles at 2 A g^(−1)and high reversibility with Coulombic efficiency of 100%;thus,signifying its bright future toward commercial application for advanced PIBs.展开更多
The Li-ion capacitors(LICs)develop rapidly due to their double-high features of high-energy density and high-power density.However,the relative low capacity of cathode and sluggish kinetics of anode seriously impede t...The Li-ion capacitors(LICs)develop rapidly due to their double-high features of high-energy density and high-power density.However,the relative low capacity of cathode and sluggish kinetics of anode seriously impede the development of LICs.Herein,the precisely pore-engineered and heteroatomtailored defective hierarchical porous carbons(DHPCs)as large-capacity cathode and high-rate anode to construct high-performance dual-carbon LICs have been developed.The DHPCs are prepared based on triple-activation mechanisms by direct pyrolysis of sustainable lignin with urea to generate the interconnected hierarchical porous structure and plentiful heteroatominduced defects.Benefiting from these advanced merits,DHPCs show the well-matched high capacity and fast kinetics of both cathode and anode,exhibiting large capacities,superior rate capability and long-term lifespan.Both experimental and computational results demonstrate the strong synergistic effect of pore and dopants for Li storage.Consequently,the assembled dual-carbon LIC exhibits high voltage of 4.5 V,high-energy density of 208 Wh kg^(−1),ultrahigh power density of 53.4 kW kg^(−1)and almost zerodecrement cycling lifetime.Impressively,the full device with high mass loading of 9.4 mg cm^(−2)on cathode still outputs high-energy density of 187 Wh kg^(−1),demonstrative of their potential as electrode materials for high-performance electrochemical devices.展开更多
Flexible zinc-ion batteries(ZIBs)are promising power sources for portable devices due to their high safety and low production cost.However,the low mass-loading and limited areal capacity of cathode materials are the m...Flexible zinc-ion batteries(ZIBs)are promising power sources for portable devices due to their high safety and low production cost.However,the low mass-loading and limited areal capacity of cathode materials are the major problems blocking the practicability of ZIBs.Herein,a high mass-loading and binder-free flexible vanadium oxide(MCV@CC)cathode with a large areal capacity was fabricated via the bridge effect of MXene.The functional MXene bridge induces the growth of the vanadium oxide active layer on the carbon cloth(CC)flexible substrate.The binder-free cathode can reduce the electrochemically inactive weight of the whole electrode,which enhances the energy density of ZIBs.Consequently,the MCV@CC cathode(mass-loading of∼7 mg cm^(−2))delivers a desirable areal capacity(2.36 mAh cm^(−2))and good cycling stability(capacity retention of 86.1%after 1200 cycles at 10 mA cm^(−2)).Moreover,several ex-situ characterization results indicate that the reaction mechanism upon battery cycling is based on the reversible Zn^(2+)/H^(+)(de)intercalation in the vanadium oxide interlayer.Furthermore,the assembled quasi-solid-state MCV@CC//Zn flexible battery exhibits decent performance at different bending states.Such a bridge effect strategy sheds light on the construction of high mass-loading flexible electrodes for ZIBs applications.展开更多
基金support by the National Natural Science Foundation of China(Nos.52074113,22005091)the Fundamental Research Funds of the Central Universities(No.531107051048)+6 种基金the Changsha Municipal Natural Science Foundantion(Grant No.43184)the CITIC Metals Ningbo Energy Co.Ltd.(No.H202191380246)Xidong Duan acknowledges support by the National Natural Science Foundation of China(Nos.51991343,51991340,61804050 and 51872086)the Hunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010)Junfei Liang acknowledges support by the National Natural Science Foundation of China(No.U1910208)the National Natural Science Foundation of Shanxi Province(No.201901D111137)Tao Wang acknowledges support by the National Natural Science Foundation of China(No.22005092).
文摘Silicon monoxide(SiO)is an attractive anode material for next-generation lithium-ion batteries for its ultra-high theoretical capacity of 2680 mAh g−1.The studies to date have been limited to electrodes with a rela-tively low mass loading(<3.5 mg cm^(−2)),which has seriously restricted the areal capacity and its potential in practical devices.Maximizing areal capacity with such high-capacity materials is critical for capitalizing their potential in practi-cal technologies.Herein,we report a monolithic three-dimensional(3D)large-sheet holey gra-phene framework/SiO(LHGF/SiO)composite for high-mass-loading electrode.By specifically using large-sheet holey graphene building blocks,we construct LHGF with super-elasticity and exceptional mechanical robustness,which is essential for accommodating the large volume change of SiO and ensuring the structure integrity even at ultrahigh mass loading.Additionally,the 3D porous graphene network structure in LHGF ensures excellent electron and ion transport.By systematically tailoring microstructure design,we show the LHGF/SiO anode with a mass loading of 44 mg cm^(−2)delivers a high areal capacity of 35.4 mAh cm^(−2)at a current of 8.8 mA cm^(−2)and retains a capacity of 10.6 mAh cm^(−2)at 17.6 mA cm^(−2),greatly exceeding those of the state-of-the-art commercial or research devices.Furthermore,we show an LHGF/SiO anode with an ultra-high mass loading of 94 mg cm^(−2)delivers an unprecedented areal capacity up to 140.8 mAh cm^(−2).The achievement of such high areal capacities marks a critical step toward realizing the full potential of high-capacity alloy-type electrode materials in practical lithium-ion batteries.
基金sponsored by the National Natural Science Foundation of China(No.51276017)
文摘The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.
基金the National Basic Research Program of China(Grant No.2015CB251100)the National Natural Science Foundation of China(Grant No.21975026)the Beijing Natural Science Foundation(Grant No.L182056).
文摘The growing demand for advanced electrochemical energy storage systems(EESSs)with high energy densities for electric vehicles and portable electronics is driving the electrode revolution,in which the development of high-mass-loading electrodes(HMLEs)is a promising route to improve the energy density of batteries packed in limited spaces through the optimal enlargement of active material loading ratios and reduction of inactive component ratios in overall cell devices.However,HMLEs face significant challenges including inferior charge kinetics,poor electrode structural stability,and complex and expensive production processes.Based on this,this review will provide a comprehensive summary of HMLEs,beginning with a basic presentation of factors influencing HMLE electrochemical properties,the understanding of which can guide optimal HMLE designs.Rational strategies to improve the electrochemical performance of HMLEs accompanied by corresponding advantages and bottlenecks are subsequently discussed in terms of various factors ranging from inactive component modification to active material design to structural engineering at the electrode scale.This review will also present the recent progress and approaches of HMLEs applied in various EESSs,including advanced secondary batteries(lithium-/sodium-/potassium-/aluminum-/calcium-ion batteries,lithium metal anodes,lithium-sulfur batteries,lithium-air batteries,zinc batteries,magnesium batteries)and supercapacitors.Finally,this review will examine the challenges and prospects of HMLE commercialization with a focus on thermal safety,performance evaluation,advanced characterization,and production cost assessment to guide future development.
基金This work was supported by the National Natural Science Fund for Distinguished Young Scholars(51425204)the National Natural Science Foundation of China(51521001,51502227,51579198,51802239)+6 种基金the National Key Research and Development Program of China(2016YFA0202603,2016YFA0202604)the Programme of Introducing Talents of Discipline to Universities(B17034)the China Postdoctoral Science Foundation(2015T80845)the Yellow Crane Talent(Science&Technology)Program of Wuhan Citythe Wuhan Morning Light Plan of Youth Science and Technology(No.2017050304010316)the Fundamental Research Funds for the Central Universities(WUT:2017III005,2017III009,2018IVA091)the Students innovation and entrepreneurship training program(WUT:20171049701005).
文摘As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most cases,constructing three-dimensional(3D)graphene networks is widely utilized to promote the permeation of electrolyte and enhance the utilization of active materials.In this work,conventional freeze-drying process is utilized in the fabrication of G-MSCs to constitute 3D interconnected networks micro-electrodes,and further by regulating the composition of inks,carbon spheres(CSs)at different mass loadings are introduced into the graphene scaffolds to further increase the active sites of the micro-electrodes.The fabricated all carbon-based MSC with the optimal mass loading of CSs(0.406 mg cm^(-2))exhibits a high specific areal capacitance of 17.01mF cm^(-2)at the scan rate of 10mV s^(-1)and a capacitance retention of 93.14%after 10000 cycles at the scan rate of 500 mV s^(-1).The proposed microfabrication process is facile and fully compatible with modern microtechnologies and will be highly suitable for large-scale production and integration.
基金supported by the National Natural Science Foundation of China(grant nos.52074113,22005091,and 22005092)the Hunan University Outstanding Youth Science Foundation(grant no.531118040319).
文摘High areal capacity is one of the critically important points for potassium-ion batteries(PIBs)for practical applications,which relies on high areal-massloading electrodes operating at high reversible capacity.However,it is remarkably restricted by the mechanical instability and sluggish charge transfer induced by the increased mass loading.To overcome such challenge,we report the rationally designed bimetallic selenides CoSe2/SnSe2 heterostructures confined in hierarchical carbon nanofibers(CSSe@CNFs),which enables the electrodes robust mechanical stability,enhanced electron transport,and reduced ion-diffusion energy barrier for facilitating reaction kinetics.Accordingly,an impressive areal mass loading up to 25.3 mg cm^(−2)was achieved,which endowed a high areal capacity of 7.58 mAh cm^(−2)for such a free-standing electrode.This is stateof-the-art among the PIBs,exceeding that of today’s industry standard(∼3 mAh cm^(−2)for LIBs).Furthermore,it delivered long-term stability over 3700 cycles at high current density(∼2 mA cm^(−2),vs 1 mA cm^(−2)in LIBs).Moreover,the as-constructed full battery achieved a high energy density of 172.8 Wh kg-1 at 0.05 A g^(−1)with a satisfied cycle stability over 2000 cycles at 2 A g^(−1)and high reversibility with Coulombic efficiency of 100%;thus,signifying its bright future toward commercial application for advanced PIBs.
基金financialy supported by National Natural Science Foundation of China(Grants 22005298,22125903,51872283,22075279,22279137)Dalian Innovation Support Plan for High Level Talents(2019RT09)+3 种基金Dalian National Laboratory For Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(DNL201912,DNL201915,DNL202016,DNL202019),DICP(DICP I2020032)The Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(YLUDNL Fund 2021002,YLU-DNL Fund 2021009)Suzhou University Scientific Research Platform(2021XJPT07)China Postdoctoral Science Foundation(2019 M661141)
文摘The Li-ion capacitors(LICs)develop rapidly due to their double-high features of high-energy density and high-power density.However,the relative low capacity of cathode and sluggish kinetics of anode seriously impede the development of LICs.Herein,the precisely pore-engineered and heteroatomtailored defective hierarchical porous carbons(DHPCs)as large-capacity cathode and high-rate anode to construct high-performance dual-carbon LICs have been developed.The DHPCs are prepared based on triple-activation mechanisms by direct pyrolysis of sustainable lignin with urea to generate the interconnected hierarchical porous structure and plentiful heteroatominduced defects.Benefiting from these advanced merits,DHPCs show the well-matched high capacity and fast kinetics of both cathode and anode,exhibiting large capacities,superior rate capability and long-term lifespan.Both experimental and computational results demonstrate the strong synergistic effect of pore and dopants for Li storage.Consequently,the assembled dual-carbon LIC exhibits high voltage of 4.5 V,high-energy density of 208 Wh kg^(−1),ultrahigh power density of 53.4 kW kg^(−1)and almost zerodecrement cycling lifetime.Impressively,the full device with high mass loading of 9.4 mg cm^(−2)on cathode still outputs high-energy density of 187 Wh kg^(−1),demonstrative of their potential as electrode materials for high-performance electrochemical devices.
基金financially supported by the National Natural Science Foundation of China (Grant No.52072094)the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environ-ments (Grant No.6142905192507)+1 种基金the Shenzhen Constantly-supported Project for Universities and Colleges in 2021 (Nos.GXWD20201230155427003-20200821232246001)the Science,Technology and Innovation Commission of Shenzhen Municipal-ity (Grant No.CJGJZD20210408092200002).
文摘Flexible zinc-ion batteries(ZIBs)are promising power sources for portable devices due to their high safety and low production cost.However,the low mass-loading and limited areal capacity of cathode materials are the major problems blocking the practicability of ZIBs.Herein,a high mass-loading and binder-free flexible vanadium oxide(MCV@CC)cathode with a large areal capacity was fabricated via the bridge effect of MXene.The functional MXene bridge induces the growth of the vanadium oxide active layer on the carbon cloth(CC)flexible substrate.The binder-free cathode can reduce the electrochemically inactive weight of the whole electrode,which enhances the energy density of ZIBs.Consequently,the MCV@CC cathode(mass-loading of∼7 mg cm^(−2))delivers a desirable areal capacity(2.36 mAh cm^(−2))and good cycling stability(capacity retention of 86.1%after 1200 cycles at 10 mA cm^(−2)).Moreover,several ex-situ characterization results indicate that the reaction mechanism upon battery cycling is based on the reversible Zn^(2+)/H^(+)(de)intercalation in the vanadium oxide interlayer.Furthermore,the assembled quasi-solid-state MCV@CC//Zn flexible battery exhibits decent performance at different bending states.Such a bridge effect strategy sheds light on the construction of high mass-loading flexible electrodes for ZIBs applications.
