Lithium-rich layered oxides(LRLOs)are promising cathode materials due to their high specific capacity,energy density,and operating voltage.However,their performance is hindered by the limited redox activity of transit...Lithium-rich layered oxides(LRLOs)are promising cathode materials due to their high specific capacity,energy density,and operating voltage.However,their performance is hindered by the limited redox activity of transition metals,leading to oxygen redox instability,oxygen release,and capacity degradation.To address these issues,we propose an innovative lattice-oxygen modulation(LOM)strategy that incorporates Mn^(3+)and Ti^(4+)into the Li_(1.2)Cr_(0.3)Mn_(0.4)Ti_(0.1)O_(2) system,effectively mitigating Cr migration,stabilizing oxygen redox reactions,and reinforcing structural integrity.This results in improved electrochemical performance,as demonstrated by a 56.5 mAh g^(−1) increase in initial discharge capacity to 364.2 mAh g^(−1),with 71.3%capacity retention after 30 cycles,reflecting a 20.2%improvement in cycling stability.Density functional theory(DFT)calculations confirm enhanced Cr redox reversibility and reduced oxygen evolution,further strengthening structural stability.These synergistic effects highlight the pivotal role of the LOM strategy in optimizing both electrochemical performance and structural integrity,offering a scalable pathway to improve capacity and cycling stability in lithium-rich cathodes.展开更多
Our previous work on the classical over-barrier ionization model for helium double ionization is extended to the complex multi-electron system of Ne. The total and q-fold ionization cross sections are calculated at en...Our previous work on the classical over-barrier ionization model for helium double ionization is extended to the complex multi-electron system of Ne. The total and q-fold ionization cross sections are calculated at energies ranging from a few tens to several hundred keV/u. The calculation results are in good agreement with the experimental data, and the energy dependence of the cross sections suggests that the multi-ionization of a strong perturbated complex atom is probably the sequential over-barrier ionization process.展开更多
Since the electrochemical energy storage was invented, mobile has brought us a new world without wires for more electronic devices [1–4]. Aluminum ion batteries(AIBs) were born with the requirements of electrochemica...Since the electrochemical energy storage was invented, mobile has brought us a new world without wires for more electronic devices [1–4]. Aluminum ion batteries(AIBs) were born with the requirements of electrochemical energy storage towards high capacity, safe and low cost.展开更多
Using the fully propagated time-dependent Hartree–Fock method, we identify that both the dynamic core polarization and multiorbital contributions are important in the attosecond transient absorption of CO molecules.T...Using the fully propagated time-dependent Hartree–Fock method, we identify that both the dynamic core polarization and multiorbital contributions are important in the attosecond transient absorption of CO molecules.The dynamics of core electrons effectively modifies the behaviors of electrons in the highest occupied molecular orbital, resulting in the modulation of intensity and position of the absorption peaks. Depending on the alignment angles, different inner orbitals are identified to contribute, and even dominate the total absorption spectra. As a result, multi-electron fingerprints are encoded in the absorption spectra, which shed light on future applications of attosecond transient absorption in complex systems.展开更多
Electrochemical batteries define the contraption stores electricity in the direct form of chemical energy with high efficiency. If the energy conversion process can be reversed, namely the input and output of electric...Electrochemical batteries define the contraption stores electricity in the direct form of chemical energy with high efficiency. If the energy conversion process can be reversed, namely the input and output of electricity both being permitted, the batteries are termed rechargeable batteries or also secondary batteries accordingly [1]. These decades have witnessed the rapid development of batteries because of the demands for transportation of information and mass in the mobile area, and stationary storage for the implementation of renewable energy technologies.展开更多
The oxidative polymerization of aryl sulfoxides provides a novel polysulfo-nium compound, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene cation) in quantita-tive yield. The polymerization proceeds efficiently in ...The oxidative polymerization of aryl sulfoxides provides a novel polysulfo-nium compound, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene cation) in quantita-tive yield. The polymerization proceeds efficiently in an acidic solution under atmosphericconditions. Oxygen, chemical and electrochemical oxidations are available. Vanadyl acety-lacetonate and cerium ammonium nitrate act as an effective catalyst for the oxygen ox-idative polymerization. The polymerization mechanism involves multielectron oxidation ofthe sulfides followed by successive electrophilic substitution. The resulting polyarylenesul-fonium cations are useful as a soluble precursor for the synthesis of high molecular weight(M_w>10~5) poly(thio arylne)s.展开更多
Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high perfo...Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.展开更多
Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- a...Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multielectron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously.展开更多
Rechargeable aluminum batteries with multi-electron reaction have a high theoretical capacity for next generation of energy storage devices. However, the diffusion mechanism and intrinsic property of Al insertion into...Rechargeable aluminum batteries with multi-electron reaction have a high theoretical capacity for next generation of energy storage devices. However, the diffusion mechanism and intrinsic property of Al insertion into MnO_(2) are not clear. Hence, based on the first-principles calculations, key influencing factors of slow Al-ions diffusion are narrow pathways, unstable Al-O bonds and Mn^(3+) type polaron have been identified by investigating four types of δ-MnO_(2)(O3, O'3, P2 and T1). Although Al insert into δ-MnO_(2) leads to a decrease in the spacing of the Mn-Mn layer, P2 type MnO_(2) keeps the long(spacious pathways)and stable(2.007–2.030 A) Al-O bonds resulting in the lower energy barrier of Al diffusion of 0.56 e V. By eliminated the influence of Mn^(3+)(low concentration of Al insertion), the energy barrier of Al migration achieves 0.19 e V in P2 type, confirming the obviously effect of Mn^(3+) polaron. On the contrary, although the T1 type MnO_(2) has the sluggish of Al-ions diffusion, the larger interlayer spacing of Mn-Mn layer,causing by H_(2)O could assist Al-ions diffusion. Furthermore, it is worth to notice that the multilayer δ-MnO_(2) achieves multi-electron reaction of 3|e|. Considering the requirement of high energy density, the average voltage of P2(1.76 V) is not an obstacle for application as cathode in RABs. These discover suggest that layered MnO_(2) should keep more P2-type structure in the synthesis of materials and increase the interlayer spacing of Mn-Mn layer for providing technical support of RABs in large-scale energy storage.展开更多
We derive a new differential formula about a kind of product of polynomials and then apply it to analyze some properties of multi-electron state ＂related to Laughlin wave function＂. The entangled state representatio...We derive a new differential formula about a kind of product of polynomials and then apply it to analyze some properties of multi-electron state ＂related to Laughlin wave function＂. The entangled state representation for describing electrons in uniform magnetic field is used.展开更多
Defect engineering acts as an efficiency method to modulate the microstructure and electronic structure of cathode for rechargeable magnesium batteries(RMBs).Owing to rich sulfur(S)vacancies tunes the electronic struc...Defect engineering acts as an efficiency method to modulate the microstructure and electronic structure of cathode for rechargeable magnesium batteries(RMBs).Owing to rich sulfur(S)vacancies tunes the electronic structure of VS4 with rich S vacancies(V_(S)-VS_(4)),the lower oxidation state of V^(3+)is induced for achieving the V^(3+)/V^(4+)and V^(4+)/V^(5+)multi-electrons reaction for Mg^(2+)storage.Amorphous structure is also constructed in VS-VS4 by chemical vapor deposition(CVD)method under the high temperature for providing fast magnesium ions(Mg^(2+))diffusion channels and expanding inner stress release space to balance the structural stability of multi-electrons reaction process.The simple defect engineering realizes the stable multi-electrons reaction in V_(S)-VS_(4) for enhancing its Mg^(2+)storage performance with higher specific capacity(158.6 mAh·g^(-1) at 50 mA·g^(-1)),stable cycling performance(capacity retention ratio of 72.7% after 3600 cycles)and the superior rate capability.This work provides electrode designing guidance for achieving stable multi-electrons to fully utilize the bivalent property of multivalence metal batteries.展开更多
Achieving multi-electron reaction at high operation voltage is the key to increase the energy density of Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode.However,the motivated V^(4+)/V^(5+)redox usually shows inferior reversibilit...Achieving multi-electron reaction at high operation voltage is the key to increase the energy density of Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode.However,the motivated V^(4+)/V^(5+)redox usually shows inferior reversibility and causes serious volume changes.Herein,this article proposes a local electronic interaction mechanism which achieves highly reversible multi-electron reaction of NVP.Particularly,Al-Sn co-doped and carbon coated NVP(Na_(3)Al_(0.1)Sn_(0.1)V_(1.8)(PO_(4))_(3)@C,abbreviated as NASVP@C-2)was prepared by sol-gel method.The doped-Al can activate the redox of V^(4+)/V^(5+)and generate the"pinning effect"to stabilize the crystal structure,and the Sn acts as localized electronic reservoir for charge compensation of V redox.The localized electronic interaction mechanism between Sn and V is revealed by multi ex-situ characterizations.Kinetics tests and density functional theory(DFT)calculations suggest that the Al-Sn co-doping enhances the electronic conductivity and reduces the Na^(+)diffusion barrier in NVP.An extremely low volumetric variation(1.07%)is detected in NASVP@C-2 during cycling.As a result,the highly reversible multielectron(2.53)reaction is achieved in NASVP@C-2,which releases a high capacity of 147.6 mAh g^(-1) at1 C and exhibits exceptional cycle stability and rate capability.This work provides a new strategy to design high energy density and durable NASICON cathode.展开更多
To address increasing energy supply challenges and allow for the effective utilization of renewable energy sources,transformational and reliable battery chemistry are critically needed to obtain higher energy densitie...To address increasing energy supply challenges and allow for the effective utilization of renewable energy sources,transformational and reliable battery chemistry are critically needed to obtain higher energy densities.Here,significant progress has been made in the past few decades in energetic battery systems based on the concept of multi-electron reactions to overcome existing barriers in conventional battery research and application.As a result,a systematic understanding of multi-electron chemistry is essential for the design of novel multi-electron reaction materials and the enhancement of corresponding battery performances.Based on this,this review will briefly present the advancements of multi-electron reaction materials from their evolutionary discovery from lightweight elements to the more recent multi-ion effect.In addition,this review will discuss representative multi-electron reaction chemistry and materials,including ferrates,metal borides,metal oxides,metal fluorides,lithium transition metal oxides,silicon,sulfur and oxygen.Furthermore,insertion-type,alloy-type and conversion-type multi-electron chemistry involving monovalent Li^(+) and Na^(+) cations,polyvalent Mg^(2+) and Al^(3+) cations beyond those of alkali metals as well as activated S^(2−) and O^(2−) anions are introduced in the enrichment and development of multi-electron reactions for electrochemical energy storage applications.Finally,this review will present the ongoing challenges and underpinning mechanisms limiting the performance of multi-electron reaction materials and corresponding battery systems.展开更多
The growing concern about scarcity and large-scale applications of lithium resources has attracted efforts to realize cost-effective phosphate-based cathode materials for next-generation Na-ion batteries(NIBs).In prev...The growing concern about scarcity and large-scale applications of lithium resources has attracted efforts to realize cost-effective phosphate-based cathode materials for next-generation Na-ion batteries(NIBs).In previous work,a series of materials(such as Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7)),Na_(3)VCr(PO_(4))_(3),Na_(4)VMn(PO_(4))3,Na_(3)MnTi(PO_(4))_(3),Na_(3)MnZr(PO_(4))3,etc)with∼120 mAh g^(-1) specific capacity and high operating potential has been proposed.However,the mass ratio of the total transition metal in the above compounds is only∼22 wt%,which means that one-electron transfer for each transition metal shows a limited capacity(the mass ratio of Fe is 35.4 wt%in LiFePO_(4)).Therefore,a multi-electron transfer reaction is necessary to catch up to or go beyond the electrochemical performance of LiFePO_(4).This review summarizes the reported NASICON-type and other phosphate-based cathode materials.On the basis of the aforementioned experimental results,we pinpoint the multi-electron behavior of transition metals and shed light on designing rules for developing high-capacity cathodes in NIBs.展开更多
现有的电子健康记录(electronic health records,EHR)的图表示学习方法多依赖单个患者的局部信息,忽视了群体患者在疾病演化和诊疗路径上的潜在关联,从而限制了模型的泛化性与鲁棒性.针对这一问题,本文提出一种混合多层级图神经网络(hyb...现有的电子健康记录(electronic health records,EHR)的图表示学习方法多依赖单个患者的局部信息,忽视了群体患者在疾病演化和诊疗路径上的潜在关联,从而限制了模型的泛化性与鲁棒性.针对这一问题,本文提出一种混合多层级图神经网络(hybrid multi-level graph neural network,H-MGNN)模型,并将其应用于重症监护室(intensive care unit,ICU)患者的死亡预测.该模型通过构建宏观层面的患者关系图(patient-patient graph,P-P)、微观层面的分类-笔记-词汇超图(taxonomy-note-word hypergraph,T-N-W),结合超图的时序依赖关系,实现多尺度上的患者特征融合.同时,本文设计了融合算法(hybrid embedding,Hybrid-E),用于提取和整合患者嵌入的潜在特征,以提升预测准确性.实验结果表明,H-MGNN在MIMIC-Ⅲ(medical information mart for intensive care Ⅲ)数据集上的住院死亡率预测等任务中显著优于现有方法,验证了其在复杂EHR数据挖掘中的有效性和先进性.展开更多
基金support from National Key R&D Program of China(2022YFB3807200)Science and Technology Commission of Shanghai Municipality(25CL2902100).
文摘Lithium-rich layered oxides(LRLOs)are promising cathode materials due to their high specific capacity,energy density,and operating voltage.However,their performance is hindered by the limited redox activity of transition metals,leading to oxygen redox instability,oxygen release,and capacity degradation.To address these issues,we propose an innovative lattice-oxygen modulation(LOM)strategy that incorporates Mn^(3+)and Ti^(4+)into the Li_(1.2)Cr_(0.3)Mn_(0.4)Ti_(0.1)O_(2) system,effectively mitigating Cr migration,stabilizing oxygen redox reactions,and reinforcing structural integrity.This results in improved electrochemical performance,as demonstrated by a 56.5 mAh g^(−1) increase in initial discharge capacity to 364.2 mAh g^(−1),with 71.3%capacity retention after 30 cycles,reflecting a 20.2%improvement in cycling stability.Density functional theory(DFT)calculations confirm enhanced Cr redox reversibility and reduced oxygen evolution,further strengthening structural stability.These synergistic effects highlight the pivotal role of the LOM strategy in optimizing both electrochemical performance and structural integrity,offering a scalable pathway to improve capacity and cycling stability in lithium-rich cathodes.
基金Project supported the by the National Natural Science Foundation of China (Grant No. 10804039)the Fundamental Research Funds for the Central Universities,China (Grant No. lzujbky-2009-24)
文摘Our previous work on the classical over-barrier ionization model for helium double ionization is extended to the complex multi-electron system of Ne. The total and q-fold ionization cross sections are calculated at energies ranging from a few tens to several hundred keV/u. The calculation results are in good agreement with the experimental data, and the energy dependence of the cross sections suggests that the multi-ionization of a strong perturbated complex atom is probably the sequential over-barrier ionization process.
基金supported by the National Natural Science Foundation of China (Grant No. 22075028)。
文摘Since the electrochemical energy storage was invented, mobile has brought us a new world without wires for more electronic devices [1–4]. Aluminum ion batteries(AIBs) were born with the requirements of electrochemical energy storage towards high capacity, safe and low cost.
基金Supported by the National Basic Research Program of China under Grant No 2013CB922203the National Natural Science Foundation of China under Grant No 11374366+1 种基金the Innovation Foundation of National University of Defense Technology under Grant No B110204the Hunan Provincial Innovation Foundation for Postgraduate under Grant No CX2011B010
文摘Using the fully propagated time-dependent Hartree–Fock method, we identify that both the dynamic core polarization and multiorbital contributions are important in the attosecond transient absorption of CO molecules.The dynamics of core electrons effectively modifies the behaviors of electrons in the highest occupied molecular orbital, resulting in the modulation of intensity and position of the absorption peaks. Depending on the alignment angles, different inner orbitals are identified to contribute, and even dominate the total absorption spectra. As a result, multi-electron fingerprints are encoded in the absorption spectra, which shed light on future applications of attosecond transient absorption in complex systems.
基金the National Basic Research Program of China (Grant Nos. 2015CB251100, 2009CB220100, 2002CB211800) for financial support。
文摘Electrochemical batteries define the contraption stores electricity in the direct form of chemical energy with high efficiency. If the energy conversion process can be reversed, namely the input and output of electricity both being permitted, the batteries are termed rechargeable batteries or also secondary batteries accordingly [1]. These decades have witnessed the rapid development of batteries because of the demands for transportation of information and mass in the mobile area, and stationary storage for the implementation of renewable energy technologies.
基金This work was partially supported by a Grant-in-Aid for Research Fellow of the Japan Society for the Promotion of Science(No.085410)and International Scientific Research(Joint Research No.08044174)from the Ministry of Education,Science,Sports and Culture
文摘The oxidative polymerization of aryl sulfoxides provides a novel polysulfo-nium compound, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene cation) in quantita-tive yield. The polymerization proceeds efficiently in an acidic solution under atmosphericconditions. Oxygen, chemical and electrochemical oxidations are available. Vanadyl acety-lacetonate and cerium ammonium nitrate act as an effective catalyst for the oxygen ox-idative polymerization. The polymerization mechanism involves multielectron oxidation ofthe sulfides followed by successive electrophilic substitution. The resulting polyarylenesul-fonium cations are useful as a soluble precursor for the synthesis of high molecular weight(M_w>10~5) poly(thio arylne)s.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,and 22379080Major Basic Research Program of the Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+1 种基金the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019。
文摘Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10874188 and 10775160)
文摘Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multielectron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously.
基金supported financially by the National Natural Science Foundation of China (No.22075028)。
文摘Rechargeable aluminum batteries with multi-electron reaction have a high theoretical capacity for next generation of energy storage devices. However, the diffusion mechanism and intrinsic property of Al insertion into MnO_(2) are not clear. Hence, based on the first-principles calculations, key influencing factors of slow Al-ions diffusion are narrow pathways, unstable Al-O bonds and Mn^(3+) type polaron have been identified by investigating four types of δ-MnO_(2)(O3, O'3, P2 and T1). Although Al insert into δ-MnO_(2) leads to a decrease in the spacing of the Mn-Mn layer, P2 type MnO_(2) keeps the long(spacious pathways)and stable(2.007–2.030 A) Al-O bonds resulting in the lower energy barrier of Al diffusion of 0.56 e V. By eliminated the influence of Mn^(3+)(low concentration of Al insertion), the energy barrier of Al migration achieves 0.19 e V in P2 type, confirming the obviously effect of Mn^(3+) polaron. On the contrary, although the T1 type MnO_(2) has the sluggish of Al-ions diffusion, the larger interlayer spacing of Mn-Mn layer,causing by H_(2)O could assist Al-ions diffusion. Furthermore, it is worth to notice that the multilayer δ-MnO_(2) achieves multi-electron reaction of 3|e|. Considering the requirement of high energy density, the average voltage of P2(1.76 V) is not an obstacle for application as cathode in RABs. These discover suggest that layered MnO_(2) should keep more P2-type structure in the synthesis of materials and increase the interlayer spacing of Mn-Mn layer for providing technical support of RABs in large-scale energy storage.
基金The project supported by National Natural Science Foundation of China under Grant No. 10475056
文摘We derive a new differential formula about a kind of product of polynomials and then apply it to analyze some properties of multi-electron state ＂related to Laughlin wave function＂. The entangled state representation for describing electrons in uniform magnetic field is used.
基金supported by the National Natural Science Foundation of China(Nos.52072196,52002200,52102106,52202262,22379081,and 22379080)Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)+1 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2020QE063,ZR202108180009,and ZR2023QE059)the Postdoctoral Program of Qingdao(No.QDBSH20220202019).
文摘Defect engineering acts as an efficiency method to modulate the microstructure and electronic structure of cathode for rechargeable magnesium batteries(RMBs).Owing to rich sulfur(S)vacancies tunes the electronic structure of VS4 with rich S vacancies(V_(S)-VS_(4)),the lower oxidation state of V^(3+)is induced for achieving the V^(3+)/V^(4+)and V^(4+)/V^(5+)multi-electrons reaction for Mg^(2+)storage.Amorphous structure is also constructed in VS-VS4 by chemical vapor deposition(CVD)method under the high temperature for providing fast magnesium ions(Mg^(2+))diffusion channels and expanding inner stress release space to balance the structural stability of multi-electrons reaction process.The simple defect engineering realizes the stable multi-electrons reaction in V_(S)-VS_(4) for enhancing its Mg^(2+)storage performance with higher specific capacity(158.6 mAh·g^(-1) at 50 mA·g^(-1)),stable cycling performance(capacity retention ratio of 72.7% after 3600 cycles)and the superior rate capability.This work provides electrode designing guidance for achieving stable multi-electrons to fully utilize the bivalent property of multivalence metal batteries.
基金financially supported by the National Natural Science Foundation of China(52462030,52464034,52364038,12464049 and 52474330)Outstanding Youth Funding program of Hunan Province(No.2023JJ10033)+5 种基金Excellent Youth Foundation of Hunan Provincial Education Department(No.23B0527,23B0528)the Natural Science Foundation of Hunan Province(No.2024JJ7399,No.2024JJ7398)Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Provincethe Hunan Provincial Undergraduate Innovation Training Program General Project(Grant No.S202410531041,No.S202310531052)the Postgraduate Research Innovation Program of Jishou University([2024]11-82)the Postgraduate Graduate Research Project of Jishou University(2023-53)。
文摘Achieving multi-electron reaction at high operation voltage is the key to increase the energy density of Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode.However,the motivated V^(4+)/V^(5+)redox usually shows inferior reversibility and causes serious volume changes.Herein,this article proposes a local electronic interaction mechanism which achieves highly reversible multi-electron reaction of NVP.Particularly,Al-Sn co-doped and carbon coated NVP(Na_(3)Al_(0.1)Sn_(0.1)V_(1.8)(PO_(4))_(3)@C,abbreviated as NASVP@C-2)was prepared by sol-gel method.The doped-Al can activate the redox of V^(4+)/V^(5+)and generate the"pinning effect"to stabilize the crystal structure,and the Sn acts as localized electronic reservoir for charge compensation of V redox.The localized electronic interaction mechanism between Sn and V is revealed by multi ex-situ characterizations.Kinetics tests and density functional theory(DFT)calculations suggest that the Al-Sn co-doping enhances the electronic conductivity and reduces the Na^(+)diffusion barrier in NVP.An extremely low volumetric variation(1.07%)is detected in NASVP@C-2 during cycling.As a result,the highly reversible multielectron(2.53)reaction is achieved in NASVP@C-2,which releases a high capacity of 147.6 mAh g^(-1) at1 C and exhibits exceptional cycle stability and rate capability.This work provides a new strategy to design high energy density and durable NASICON cathode.
基金support from the National Basic Research Program of China(Grant Nos.2015CB251100,2009CB220100,2002CB211800)the National Natural Science Foundation of China(Grant Nos.21975026,51804290)+2 种基金the Beijing Natural Science Foundation(Grant Nos.L182023,L182056).G.Tan acknowledges the support from Beijing Institute of Technology Teli Young Fellow Program(No.3090011181903)X.Wang thanks the support from the Beijing Institute of Technology Research Fund Program for Young Scholars(2019CX04092).
文摘To address increasing energy supply challenges and allow for the effective utilization of renewable energy sources,transformational and reliable battery chemistry are critically needed to obtain higher energy densities.Here,significant progress has been made in the past few decades in energetic battery systems based on the concept of multi-electron reactions to overcome existing barriers in conventional battery research and application.As a result,a systematic understanding of multi-electron chemistry is essential for the design of novel multi-electron reaction materials and the enhancement of corresponding battery performances.Based on this,this review will briefly present the advancements of multi-electron reaction materials from their evolutionary discovery from lightweight elements to the more recent multi-ion effect.In addition,this review will discuss representative multi-electron reaction chemistry and materials,including ferrates,metal borides,metal oxides,metal fluorides,lithium transition metal oxides,silicon,sulfur and oxygen.Furthermore,insertion-type,alloy-type and conversion-type multi-electron chemistry involving monovalent Li^(+) and Na^(+) cations,polyvalent Mg^(2+) and Al^(3+) cations beyond those of alkali metals as well as activated S^(2−) and O^(2−) anions are introduced in the enrichment and development of multi-electron reactions for electrochemical energy storage applications.Finally,this review will present the ongoing challenges and underpinning mechanisms limiting the performance of multi-electron reaction materials and corresponding battery systems.
基金supported by the National Key R&D Program of China(2022YFB3807800)National Natural Science Foundation(NSFC)of China(51725206,52122214,52002394,and 52072403)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020006).
文摘The growing concern about scarcity and large-scale applications of lithium resources has attracted efforts to realize cost-effective phosphate-based cathode materials for next-generation Na-ion batteries(NIBs).In previous work,a series of materials(such as Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7)),Na_(3)VCr(PO_(4))_(3),Na_(4)VMn(PO_(4))3,Na_(3)MnTi(PO_(4))_(3),Na_(3)MnZr(PO_(4))3,etc)with∼120 mAh g^(-1) specific capacity and high operating potential has been proposed.However,the mass ratio of the total transition metal in the above compounds is only∼22 wt%,which means that one-electron transfer for each transition metal shows a limited capacity(the mass ratio of Fe is 35.4 wt%in LiFePO_(4)).Therefore,a multi-electron transfer reaction is necessary to catch up to or go beyond the electrochemical performance of LiFePO_(4).This review summarizes the reported NASICON-type and other phosphate-based cathode materials.On the basis of the aforementioned experimental results,we pinpoint the multi-electron behavior of transition metals and shed light on designing rules for developing high-capacity cathodes in NIBs.
文摘现有的电子健康记录(electronic health records,EHR)的图表示学习方法多依赖单个患者的局部信息,忽视了群体患者在疾病演化和诊疗路径上的潜在关联,从而限制了模型的泛化性与鲁棒性.针对这一问题,本文提出一种混合多层级图神经网络(hybrid multi-level graph neural network,H-MGNN)模型,并将其应用于重症监护室(intensive care unit,ICU)患者的死亡预测.该模型通过构建宏观层面的患者关系图(patient-patient graph,P-P)、微观层面的分类-笔记-词汇超图(taxonomy-note-word hypergraph,T-N-W),结合超图的时序依赖关系,实现多尺度上的患者特征融合.同时,本文设计了融合算法(hybrid embedding,Hybrid-E),用于提取和整合患者嵌入的潜在特征,以提升预测准确性.实验结果表明,H-MGNN在MIMIC-Ⅲ(medical information mart for intensive care Ⅲ)数据集上的住院死亡率预测等任务中显著优于现有方法,验证了其在复杂EHR数据挖掘中的有效性和先进性.
