Halide electrolytes,renowned for their excellent electrochemical stability and wide voltage window,exhibit significant potential in the development of high energy density solid-state batteries featuring high voltage c...Halide electrolytes,renowned for their excellent electrochemical stability and wide voltage window,exhibit significant potential in the development of high energy density solid-state batteries featuring high voltage cathode materials.In this study,we present the development and synthesis of a 0.6Li_(2)S-ZrCl_(4)solid electrolyte,demonstrating an ion conductivity of 1.9×10^(–3)S/cm at 25°C.Under a pressure of 500 MPa,the relative density of the electrolyte can reach 97.37%,showcasing its commendable compressibility.0.6Li_(2)S-ZrCl_(4)served as the electrolyte,and we assembled batteries utilizing a LiCoO_(2)(LCO)positive electrode,Li_(9.54)Si_(1.74)P_(1.44)S_(11.7)Cl_(0.3)(LSPSCl)coating,and Li-In negative electrode for laboratory testing.At 25°C,this all-solid-state battery demonstrated an impressive discharge capacity retention rate of86.99%(with a final discharge specific capacity of 110.5 m Ah/g)after 250 cycles at 24 m A/g and 100 MPa stack pressure.Upon substituting the positive electrode material with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)and assembling an all-solid-state battery,it demonstrated a discharge capacity retention rate of 74.17%after200 cycles at 3.6 m A/g and 100 MPa stack pressure in an environment at 25°C(with a final discharge specific capacity of 103.3 m A/g).Our findings hold significant implications for the design of novel superionic conductors,thereby contributing to the advancement of all-solid-state battery technology.展开更多
Transition metal dichalcogenides(TMDs)have widespread applications in the fields of optoelectronics and catalysis.Generally,1T phase TMDs have more edge active sites than 2H phase TMDs and thus exhibit superior cataly...Transition metal dichalcogenides(TMDs)have widespread applications in the fields of optoelectronics and catalysis.Generally,1T phase TMDs have more edge active sites than 2H phase TMDs and thus exhibit superior catalytic efficiency.However,it remains challenging to prepare 1T phase TMDs to date.In this study,we found that when two 2H phase tungsten disulfide(2H-WS_(2))grains with large crystallographic orientation differences(>10°)come into contact at a temperature of 1000℃,they can combine and further transform into one pure 1T phase tungsten disulfide(1T-WS_(2))grain without crystallographic orientation differences.The first-principles calculation showed that at a temperature lower than 280 K,the 2H-WS_(2)is a stable phase and 1T-WS_(2)is a metastable phase.But when the temperature is higher than 280 K,their relative stability turns.In the kinetic analysis of 2H to 1T phase nucleation,homogeneous nucleation needs to cross the energy barrier of 2.314 eV,while the heterogeneous nucleation of two nanosheets in contact only needs to cross the energy barrier of 0.005 eV,which is more prone to phase transformation.This work presents a novel approach for synthesizing 1T-WS_(2)and may provide a strategy for synthesizing other 1T phase TMDs.展开更多
The integration of large-scale wind power brings challenges to the operation of integrated energy systems(IES).In this paper,a day-ahead scheduling model for IES with wind power and multi-type energy storage is propos...The integration of large-scale wind power brings challenges to the operation of integrated energy systems(IES).In this paper,a day-ahead scheduling model for IES with wind power and multi-type energy storage is proposed in a scenario-based stochastic programming framework.The structure of the IES consists of electricity,natural gas,and heating networks which are all included in the model.Operational constraints for IES incorporating multi-type energy storage devices are also considered.The constraints of the electricity network,natural gas network and heating network are formulated,and non-linear constraints are linearized.The calculation method for the correlation of wind speed between wind farms based on historical data is proposed.Uncertainties of correlated wind power were represented by creating multiple representative scenarios with different probabilities,and this was done using the Latin hyper-cube sampling(LHS)method.The stochastic scheduling model is formulated as a mixed integer linear programming(MILP)problem with the objective function of minimizing the total expected operation cost.Numerical results on a modified PJM 5-bus electricity system with a seven-node natural gas system and a six-node heating system validate the proposed model.The results demonstrate that multi-type energy storage devices can help reduce wind power curtailments and improve the operational flexibility of IES.展开更多
The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mi...The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mismatch between generation and load demand because of their intermittent nature.The traditional way of dealing with this problem is to increase the spinning reserve,which is quite costly.In recent years,it has been proposed that part of the load can be controlled dynamically for frequency regulation with little impact on customers’living comfort.This paper proposes a hybrid dynamic demand control(DDC)strategy for the primary and secondary frequency regulation.In particular,the loads can not only arrest the sudden frequency drop,but also bring the frequency closer to the nominal value.With the proposed control strategy,the demand side can provide a fast and smooth frequency regulation service,thereby replacing some generation reserve to achieve a lower expense.展开更多
Two-dimensional amorphous carbon(2DAC)materials possess characteristics such as high conductivity,high flexibility,and chemical stability,making them promising for applications in electronics,sensors,catalysts,superco...Two-dimensional amorphous carbon(2DAC)materials possess characteristics such as high conductivity,high flexibility,and chemical stability,making them promising for applications in electronics,sensors,catalysts,superconductors,energy storage,and energy conversion.However,it is still a challenge to directly synthesize 2DAC till now.Meanwhile,many controversies exist in their formation process and structure.Therefore,this article utilizes a top-down etching method to prepare 2DAC in environmental transmission electron microscope(ETEM).By employing electron beam irradiation combined with heating at 650°C in an oxygen atmosphere(0.01 mbar),controllable fabrication of 2DAC is achieved.In this process,the raw diamond sheet first transforms into graphite,and as the reaction goes on,the amount of graphite increases,eventually transitioning into 2DAC.First-principles calculations indicate that it is an energy-favorable process from diamond to graphite.Although there is an energy barrier for graphite-to-amorphous carbon transition,electron beam irradiation induces numerous defects that can overcome this barrier.This method not only fabricates 2DAC with atomic precision but also provides in-situ analysis of its formation process.The research findings contribute to a fundamental understanding of the formation process of 2DAC and offer new insights for the preparation of 2D ultrathin amorphous materials.展开更多
基金financially supported by Natural Science Foundation of Hebei Province(Nos.B2020203037,F2021203097)Science Research Project of Hebei Education Department(No.JZX2024022)National Natural Science Foundation of China(Nos.52022088,51971245)。
文摘Halide electrolytes,renowned for their excellent electrochemical stability and wide voltage window,exhibit significant potential in the development of high energy density solid-state batteries featuring high voltage cathode materials.In this study,we present the development and synthesis of a 0.6Li_(2)S-ZrCl_(4)solid electrolyte,demonstrating an ion conductivity of 1.9×10^(–3)S/cm at 25°C.Under a pressure of 500 MPa,the relative density of the electrolyte can reach 97.37%,showcasing its commendable compressibility.0.6Li_(2)S-ZrCl_(4)served as the electrolyte,and we assembled batteries utilizing a LiCoO_(2)(LCO)positive electrode,Li_(9.54)Si_(1.74)P_(1.44)S_(11.7)Cl_(0.3)(LSPSCl)coating,and Li-In negative electrode for laboratory testing.At 25°C,this all-solid-state battery demonstrated an impressive discharge capacity retention rate of86.99%(with a final discharge specific capacity of 110.5 m Ah/g)after 250 cycles at 24 m A/g and 100 MPa stack pressure.Upon substituting the positive electrode material with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)and assembling an all-solid-state battery,it demonstrated a discharge capacity retention rate of 74.17%after200 cycles at 3.6 m A/g and 100 MPa stack pressure in an environment at 25°C(with a final discharge specific capacity of 103.3 m A/g).Our findings hold significant implications for the design of novel superionic conductors,thereby contributing to the advancement of all-solid-state battery technology.
基金financially supported by the National Natural Science Foundation of China(52471018,52401298,51925105,U24A20076,U23A20537)the S&T Program of Hebei(B2023203037,B2024203054)+1 种基金the Science Research Project of Hebei Education Department(JZX2024022)the Central Guidance Fund for Local Science and Technology Development Project(246Z1101G)。
文摘Transition metal dichalcogenides(TMDs)have widespread applications in the fields of optoelectronics and catalysis.Generally,1T phase TMDs have more edge active sites than 2H phase TMDs and thus exhibit superior catalytic efficiency.However,it remains challenging to prepare 1T phase TMDs to date.In this study,we found that when two 2H phase tungsten disulfide(2H-WS_(2))grains with large crystallographic orientation differences(>10°)come into contact at a temperature of 1000℃,they can combine and further transform into one pure 1T phase tungsten disulfide(1T-WS_(2))grain without crystallographic orientation differences.The first-principles calculation showed that at a temperature lower than 280 K,the 2H-WS_(2)is a stable phase and 1T-WS_(2)is a metastable phase.But when the temperature is higher than 280 K,their relative stability turns.In the kinetic analysis of 2H to 1T phase nucleation,homogeneous nucleation needs to cross the energy barrier of 2.314 eV,while the heterogeneous nucleation of two nanosheets in contact only needs to cross the energy barrier of 0.005 eV,which is more prone to phase transformation.This work presents a novel approach for synthesizing 1T-WS_(2)and may provide a strategy for synthesizing other 1T phase TMDs.
基金This paper was supported in part by National Natural Science Foundation of China(Grant No.51677022,51607033,and 51607034)National Key Research and Development Program of China(2017YFB0903400)+1 种基金Integrated Energy System Innovation Team of Jilin Province(20180519015JH)and International Clean Energy Talent Programme(iCET)of China Scholarship Council.
文摘The integration of large-scale wind power brings challenges to the operation of integrated energy systems(IES).In this paper,a day-ahead scheduling model for IES with wind power and multi-type energy storage is proposed in a scenario-based stochastic programming framework.The structure of the IES consists of electricity,natural gas,and heating networks which are all included in the model.Operational constraints for IES incorporating multi-type energy storage devices are also considered.The constraints of the electricity network,natural gas network and heating network are formulated,and non-linear constraints are linearized.The calculation method for the correlation of wind speed between wind farms based on historical data is proposed.Uncertainties of correlated wind power were represented by creating multiple representative scenarios with different probabilities,and this was done using the Latin hyper-cube sampling(LHS)method.The stochastic scheduling model is formulated as a mixed integer linear programming(MILP)problem with the objective function of minimizing the total expected operation cost.Numerical results on a modified PJM 5-bus electricity system with a seven-node natural gas system and a six-node heating system validate the proposed model.The results demonstrate that multi-type energy storage devices can help reduce wind power curtailments and improve the operational flexibility of IES.
基金supported by the Engineering Research Center Program of the National Science Foundationthe Department of Energy of USA under NSF Award Number EEC-1041877the CURENT Industry Partnership Program.
文摘The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mismatch between generation and load demand because of their intermittent nature.The traditional way of dealing with this problem is to increase the spinning reserve,which is quite costly.In recent years,it has been proposed that part of the load can be controlled dynamically for frequency regulation with little impact on customers’living comfort.This paper proposes a hybrid dynamic demand control(DDC)strategy for the primary and secondary frequency regulation.In particular,the loads can not only arrest the sudden frequency drop,but also bring the frequency closer to the nominal value.With the proposed control strategy,the demand side can provide a fast and smooth frequency regulation service,thereby replacing some generation reserve to achieve a lower expense.
基金financially supported by the National Natural Science Foundation of China(52471018,52401298,51925105 and U23A20537)the S&T Program of Hebei(B2023203037 and B2024203054)+1 种基金the Science Research Project of Hebei Education Department(JZX2024022)the Central Guidance Fund for Local Science and Technology Development Project(246Z1101G)。
文摘Two-dimensional amorphous carbon(2DAC)materials possess characteristics such as high conductivity,high flexibility,and chemical stability,making them promising for applications in electronics,sensors,catalysts,superconductors,energy storage,and energy conversion.However,it is still a challenge to directly synthesize 2DAC till now.Meanwhile,many controversies exist in their formation process and structure.Therefore,this article utilizes a top-down etching method to prepare 2DAC in environmental transmission electron microscope(ETEM).By employing electron beam irradiation combined with heating at 650°C in an oxygen atmosphere(0.01 mbar),controllable fabrication of 2DAC is achieved.In this process,the raw diamond sheet first transforms into graphite,and as the reaction goes on,the amount of graphite increases,eventually transitioning into 2DAC.First-principles calculations indicate that it is an energy-favorable process from diamond to graphite.Although there is an energy barrier for graphite-to-amorphous carbon transition,electron beam irradiation induces numerous defects that can overcome this barrier.This method not only fabricates 2DAC with atomic precision but also provides in-situ analysis of its formation process.The research findings contribute to a fundamental understanding of the formation process of 2DAC and offer new insights for the preparation of 2D ultrathin amorphous materials.
