Currently,although some progress has been made in infancy-stage rocking-chair aqueous zinc-ion batteries(AZIBs),more discussions have focused only on the different electrochemical performances displayed by different m...Currently,although some progress has been made in infancy-stage rocking-chair aqueous zinc-ion batteries(AZIBs),more discussions have focused only on the different electrochemical performances displayed by different material types rather than the intrinsic ion transport migration electrochemistry.Herein,we for the first time delve into the mechanism of tailoring the solvation sheath and desolvation processes at the electrode/electrolyte interfaces to enhance the structural stabilities in the deep discharge states.In this work,the TiO_(2)front interfaces are induced on electrochemically active but unstable TiSe_(2)host materials to construct unique TiO_(2)/TiSe_(2)-C heterointerfaces.According to X-ray absorption near edge structure(XANES),differential electrochemical mass spectrometry(DEMS),and electrochemical quartz crystal microbalance(EQCM),the intercalated species are transformed from[Zn(H_(2)O)_(6)]^(2+)to[Zn(H_(2)O)_(2)]^(2+)due to the built-in electric fields(BEFs)effects,further accelerating the ion transfer kinetics.Furthermore,owing to the absence of high-energy desolvation solvents released from desolvation processes,hydrogen evolution reaction(HER)energy barriers,Ti-Se bond strength,and structural stabilities are significantly improved,and the initial CE and HER overpotentials of the TiO_(2)/TiSe_(2)-C heterointerfaces increased from 13.76%to 84.7%,and from 1.04 to 1.30 V,respectively,and the H2 precipitation current density even at-1.3 V decreased by 73.2%.This work provides valuable insights into the complex interface electrochemical mechanism of tailoring the solvation sheath and desolvation processes toward rocking-chair zinc-ion batteries.展开更多
Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerati...Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerating interfaces decay.Herein,we propose for the first time a novel strategy to enhance the interfacial stabilities by insitu dynamic reconstruction of weakly solvated Zn2þduring the desolvation processes at heterointerfaces.Theoretical calculations indicate that,due to built-in electric field effects(BEFs),the plating/stripping mechanism shifts from[Zn(H_(2)O)_(6)]_(2)þto[Zn(H_(2)O)_(5)(SO_(4))^(2-)]_(2)þwithout additional electrolyte additives,reducing the solvation ability of H_(2)O,enhancing the competitive coordination of SO_(4)^(2-),essentially eliminating the undesirable side effects of anodes.Hence,symmetric cells can operate stably for 3000 h(51.7-times increase in cycle life),and the full cells can operate stably for 5000 cycles(51.5-times increase in cycle life).This study provides valuable insights into the critical design of weakly solvated Zn^(2+) þand desolvation processes at heterointerfaces.展开更多
Overcoming the trade-offbetween saturation magnetic induction(B_(s))and coercivity(H_(c))of Fe-based nanocrystalline alloys(FNAs)remains a great challenge due to the traditional design relying on trial-anderror method...Overcoming the trade-offbetween saturation magnetic induction(B_(s))and coercivity(H_(c))of Fe-based nanocrystalline alloys(FNAs)remains a great challenge due to the traditional design relying on trial-anderror methods,which are time-consuming and inefficient.Herein,we present an interpretable machine learning(ML)algorithm for the effective design of advanced FNAs with improved B_(s)and low H_(c).Firstly,the FNAs datasets were established,consisting of 20 features including chemical composition,process parameters,and theoretically calculated parameters.Subsequently,a three-step feature selection was used to screen the key features that affect the B_(s)and H_(c)of FNAs.Among six different ML algorithms,extreme gradient boosting(XGBoost)performed the best in predicting B_(s)and H_(c).We further revealed the association of key features with B_(s)and H_(c)through linear regression and SHAP analysis.The valence electron concentration without Fe,Ni,and Co elements(VEC1)and valence electron concentration(VEC)ranked as the most important features for predicting B_(s)and H_(c),respectively.VEC1 had a positive impact on B_(s)when VEC1<0.78,while VEC had a negative effect on H_(c)when VEC<7.12.Optimized designed FNAs were successfully prepared,and the prediction errors for B_(s)and H_(c)are lower than 2.3%and 18%,respectively,when comparing the predicted and experimental results.These results demonstrate that this ML approach is interpretable and feasible for the design of advanced FNAs with high B_(s)and low H_(c).展开更多
The lack of methods to modulate intrinsic textures of carbon cathode has seriously hindered the revelation of in-depth relationship between inherent natures and capacitive behaviors,limiting the advancement of lithium...The lack of methods to modulate intrinsic textures of carbon cathode has seriously hindered the revelation of in-depth relationship between inherent natures and capacitive behaviors,limiting the advancement of lithium ion capacitors(LICs).Here,an orientateddesigned pore size distribution(range from 0.5 to 200 nm)and graphitization engineering strategy of carbon materials through regulating molar ratios of Zn/Co ions has been proposed,which provides an effective platform to deeply evaluate the capacitive behaviors of carbon cathode.Significantly,after the systematical analysis cooperating with experimental result and density functional theory calculation,it is uncovered that the size of solvated PF6-ion is about 1.5 nm.Moreover,the capacitive behaviors of carbon cathode could be enhanced attributed to the controlled pore size of 1.5-3 nm.Triggered with synergistic effect of graphitization and appropriate pore size distribution,optimized carbon cathode(Zn90Co10-APC)displays excellent capacitive performances with a reversible specific capacity of^50 mAh g-1at a current density of 5 A g-1.Furthermore,the assembly pre-lithiated graphite(PLG)//Zn90Co10-APC LIC could deliver a large energy density of 108 Wh kg-1 and a high power density of 150,000 W kg-1 as well as excellent long-term ability with 10,000 cycles.This elaborate work might shed light on the intensive understanding of the improved capacitive behavior in LiPF<sub>6 electrolyte and provide a feasible principle for elaborate fabrication of carbon cathodes for LIC systems.展开更多
Based on the excellent sodium ion mobility of sodium superionic conductor structures,Na_(3)V_(2)(PO_(4))_(3)materials have become promising cathode materials in sodium-ion batteries(SIBs).However,inadequate electronic...Based on the excellent sodium ion mobility of sodium superionic conductor structures,Na_(3)V_(2)(PO_(4))_(3)materials have become promising cathode materials in sodium-ion batteries(SIBs).However,inadequate electronic transport of Na_(3)V_(2)(PO_(4))_(3)limits the cycling stability and rate performances in SIBs.In this work,high-performance conductive carbon-coated Na_(3)V_(2)(PO_(4))_(3)materials are obtained via a simple and facile ball-milling assisted solid-state method by utilizing citric acid as carbon sources.The carbon-coated composite electrodes display a high initial specific capacity of 111.6 mAh·g^(-1),and the specific capacity could retention reach 92.83%after 100 cycles at 1C with the high coulombic efficiency(99.95%).More importantly,the capacity of conductive carbon-coated nano-sized Na_(3)V_(2)(PO_(4))_(3)can remain 48.5 mAh·g^(-1) at 10℃after 3000 cycles(initial capacity of 101.2 mAh·g^(-1)).At the same time,high coulombic efficiency(near 100%)has little decay even at a high rate of 20℃during 1000 cycles,demonstrating the excellent cycling stability and remarkable rate performances,and showing potential in largescale productions and applications.展开更多
High-performance lithium ion capacitors(LICs) have been seriously hindered by the very low capacity and unclear capacitive mechanism of carbon cathode.Herein,after the combination of experimental results and theoretic...High-performance lithium ion capacitors(LICs) have been seriously hindered by the very low capacity and unclear capacitive mechanism of carbon cathode.Herein,after the combination of experimental results and theoretical calculations,it is found that the critical pore size of 0.8 nm for PF_6~-ion adsorption decreases strong interactive repulsion of electrons and largely reduces adsorption energy barrier,which greatly improves the charge accommodation capacity in electrical double-layer behavior.Most importantly,the chemical-bond evolution process of C=O group has been firstly revealed by X-ray photoelectron spectroscopy(XPS),indicating that the introduction of C=O group can provide abundant redox active sites for PF_6~-ion adsorption accompanied with enhanced pseudocapacitive capacity.Attributed to the synergistic effect of dual capacitive mechanism,porous carbon sheet(PCS) cathode shows a reversible specific capacity of 53.6 mAh g^(-1) even at a high current density of 50 A g^(-1).Significantly,the quasisolid-state LIC manifests state-of-the-art electrochemical performances with an integrated maximum energy density of 163 Wh kg^(-1) and an outstanding power density of 15,000 W kg^(-1).This elaborate work promotes better fundamental understanding about capacitive mechanism of PF_6~-ion and offers a rational dual-capacitive strategy for the design of advanced carbon cathodes.展开更多
Carbon-based materials have attracted much interest as one of the promising anodes for sodium-ion batteries. However, low utilization of electrolyte and slow ion-transfer rate during electrochemical process hinder the...Carbon-based materials have attracted much interest as one of the promising anodes for sodium-ion batteries. However, low utilization of electrolyte and slow ion-transfer rate during electrochemical process hinder the further application of traditional bulk carbon. In order to enhance the diffusion kinetics and maintain the reversibility, hierarchical hollow carbon microbox was successfully prepared through a tunable bottom-up self-template routine for sodium-ion batteries. During annealing process, the morphology construction and activation happened synchronously. Based on that, a range of cross-linked porous nanosheet and hollow microbox were attained by manipulating reactant condition. The generation of texture and physical property are analyzed and are established linkages related to the electrochemical behavior. As results depicted in kinetic exploration and simulation based on cyclic voltammetry, the surfacecontrolled electrochemical behavior gradually turns to be the diffusion-controlled behavior as the hollow microbox evolves to porous nanosheet. The probable reason is that the rational microstructure/texture design leads to the accelerated diffusion kinetic procedure and the reduced concentration difference polarization. Sodium storage mechanism was deduced as reversible binding of Na-ions with local defects,including vacancies on sp2 graphitic layers, at the edges of flakes and other structural defects instead of intercalation. Bestowed by the morphology design, the broad pore width distribution, abundant defects/active sites and surface functionality, hollow microbox electrode delivers great electrochemical performances. This work is expected to propose a novel and effective strategy to prepare tunable hierarchical hollow carbon microbox and induce the fast kinetic of carbon anode material.展开更多
基金supported by the National Natural Science Foundation of China(51977097).
文摘Currently,although some progress has been made in infancy-stage rocking-chair aqueous zinc-ion batteries(AZIBs),more discussions have focused only on the different electrochemical performances displayed by different material types rather than the intrinsic ion transport migration electrochemistry.Herein,we for the first time delve into the mechanism of tailoring the solvation sheath and desolvation processes at the electrode/electrolyte interfaces to enhance the structural stabilities in the deep discharge states.In this work,the TiO_(2)front interfaces are induced on electrochemically active but unstable TiSe_(2)host materials to construct unique TiO_(2)/TiSe_(2)-C heterointerfaces.According to X-ray absorption near edge structure(XANES),differential electrochemical mass spectrometry(DEMS),and electrochemical quartz crystal microbalance(EQCM),the intercalated species are transformed from[Zn(H_(2)O)_(6)]^(2+)to[Zn(H_(2)O)_(2)]^(2+)due to the built-in electric fields(BEFs)effects,further accelerating the ion transfer kinetics.Furthermore,owing to the absence of high-energy desolvation solvents released from desolvation processes,hydrogen evolution reaction(HER)energy barriers,Ti-Se bond strength,and structural stabilities are significantly improved,and the initial CE and HER overpotentials of the TiO_(2)/TiSe_(2)-C heterointerfaces increased from 13.76%to 84.7%,and from 1.04 to 1.30 V,respectively,and the H2 precipitation current density even at-1.3 V decreased by 73.2%.This work provides valuable insights into the complex interface electrochemical mechanism of tailoring the solvation sheath and desolvation processes toward rocking-chair zinc-ion batteries.
基金financially supported by the National Natural Science Foundation of China(51977097).
文摘Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerating interfaces decay.Herein,we propose for the first time a novel strategy to enhance the interfacial stabilities by insitu dynamic reconstruction of weakly solvated Zn2þduring the desolvation processes at heterointerfaces.Theoretical calculations indicate that,due to built-in electric field effects(BEFs),the plating/stripping mechanism shifts from[Zn(H_(2)O)_(6)]_(2)þto[Zn(H_(2)O)_(5)(SO_(4))^(2-)]_(2)þwithout additional electrolyte additives,reducing the solvation ability of H_(2)O,enhancing the competitive coordination of SO_(4)^(2-),essentially eliminating the undesirable side effects of anodes.Hence,symmetric cells can operate stably for 3000 h(51.7-times increase in cycle life),and the full cells can operate stably for 5000 cycles(51.5-times increase in cycle life).This study provides valuable insights into the critical design of weakly solvated Zn^(2+) þand desolvation processes at heterointerfaces.
基金supported by the National Key R&D Program of China(Grant No.2022YFB2404101)the“Pioneer”R&D Programof Zhejiang Province(No.2023C01075)+1 种基金the Youth Innovation Promotion Association CAS(Grant No.2021294)the Ningbo Natural Science Foundation(No.2021J197).
文摘Overcoming the trade-offbetween saturation magnetic induction(B_(s))and coercivity(H_(c))of Fe-based nanocrystalline alloys(FNAs)remains a great challenge due to the traditional design relying on trial-anderror methods,which are time-consuming and inefficient.Herein,we present an interpretable machine learning(ML)algorithm for the effective design of advanced FNAs with improved B_(s)and low H_(c).Firstly,the FNAs datasets were established,consisting of 20 features including chemical composition,process parameters,and theoretically calculated parameters.Subsequently,a three-step feature selection was used to screen the key features that affect the B_(s)and H_(c)of FNAs.Among six different ML algorithms,extreme gradient boosting(XGBoost)performed the best in predicting B_(s)and H_(c).We further revealed the association of key features with B_(s)and H_(c)through linear regression and SHAP analysis.The valence electron concentration without Fe,Ni,and Co elements(VEC1)and valence electron concentration(VEC)ranked as the most important features for predicting B_(s)and H_(c),respectively.VEC1 had a positive impact on B_(s)when VEC1<0.78,while VEC had a negative effect on H_(c)when VEC<7.12.Optimized designed FNAs were successfully prepared,and the prediction errors for B_(s)and H_(c)are lower than 2.3%and 18%,respectively,when comparing the predicted and experimental results.These results demonstrate that this ML approach is interpretable and feasible for the design of advanced FNAs with high B_(s)and low H_(c).
基金financially supported by National Key Research and Development Program of China(2018YFC1901605)the National Postdoctoral Program for Innovative Talents(BX201600192)+1 种基金Hunan Provincial Science and Technology Plan(2017TP1001)Innovation Mover Program of Central South University(GCX20190893Y)。
文摘The lack of methods to modulate intrinsic textures of carbon cathode has seriously hindered the revelation of in-depth relationship between inherent natures and capacitive behaviors,limiting the advancement of lithium ion capacitors(LICs).Here,an orientateddesigned pore size distribution(range from 0.5 to 200 nm)and graphitization engineering strategy of carbon materials through regulating molar ratios of Zn/Co ions has been proposed,which provides an effective platform to deeply evaluate the capacitive behaviors of carbon cathode.Significantly,after the systematical analysis cooperating with experimental result and density functional theory calculation,it is uncovered that the size of solvated PF6-ion is about 1.5 nm.Moreover,the capacitive behaviors of carbon cathode could be enhanced attributed to the controlled pore size of 1.5-3 nm.Triggered with synergistic effect of graphitization and appropriate pore size distribution,optimized carbon cathode(Zn90Co10-APC)displays excellent capacitive performances with a reversible specific capacity of^50 mAh g-1at a current density of 5 A g-1.Furthermore,the assembly pre-lithiated graphite(PLG)//Zn90Co10-APC LIC could deliver a large energy density of 108 Wh kg-1 and a high power density of 150,000 W kg-1 as well as excellent long-term ability with 10,000 cycles.This elaborate work might shed light on the intensive understanding of the improved capacitive behavior in LiPF<sub>6 electrolyte and provide a feasible principle for elaborate fabrication of carbon cathodes for LIC systems.
基金This work was financially supported by the National Key Research and Development Program of China(No.2017YFB0102000)Major Program of the National Natural Science Foundation of China(No.51890865)the State Key Program of National Natural Science of China(No.61835014).
文摘Based on the excellent sodium ion mobility of sodium superionic conductor structures,Na_(3)V_(2)(PO_(4))_(3)materials have become promising cathode materials in sodium-ion batteries(SIBs).However,inadequate electronic transport of Na_(3)V_(2)(PO_(4))_(3)limits the cycling stability and rate performances in SIBs.In this work,high-performance conductive carbon-coated Na_(3)V_(2)(PO_(4))_(3)materials are obtained via a simple and facile ball-milling assisted solid-state method by utilizing citric acid as carbon sources.The carbon-coated composite electrodes display a high initial specific capacity of 111.6 mAh·g^(-1),and the specific capacity could retention reach 92.83%after 100 cycles at 1C with the high coulombic efficiency(99.95%).More importantly,the capacity of conductive carbon-coated nano-sized Na_(3)V_(2)(PO_(4))_(3)can remain 48.5 mAh·g^(-1) at 10℃after 3000 cycles(initial capacity of 101.2 mAh·g^(-1)).At the same time,high coulombic efficiency(near 100%)has little decay even at a high rate of 20℃during 1000 cycles,demonstrating the excellent cycling stability and remarkable rate performances,and showing potential in largescale productions and applications.
基金financially supported by the National Key Research and Development Program of China (2018YFC1901605)the National Natural Science Foundation of China (52004338)+2 种基金the Hunan Provincial Natural Science Foundation of China (2020JJ5696)the Guangdong Provincial Department of Natural Resources (2020-011)the Fundamental Research Funds for the Central Universities of Central South University (2020zzts058)。
文摘High-performance lithium ion capacitors(LICs) have been seriously hindered by the very low capacity and unclear capacitive mechanism of carbon cathode.Herein,after the combination of experimental results and theoretical calculations,it is found that the critical pore size of 0.8 nm for PF_6~-ion adsorption decreases strong interactive repulsion of electrons and largely reduces adsorption energy barrier,which greatly improves the charge accommodation capacity in electrical double-layer behavior.Most importantly,the chemical-bond evolution process of C=O group has been firstly revealed by X-ray photoelectron spectroscopy(XPS),indicating that the introduction of C=O group can provide abundant redox active sites for PF_6~-ion adsorption accompanied with enhanced pseudocapacitive capacity.Attributed to the synergistic effect of dual capacitive mechanism,porous carbon sheet(PCS) cathode shows a reversible specific capacity of 53.6 mAh g^(-1) even at a high current density of 50 A g^(-1).Significantly,the quasisolid-state LIC manifests state-of-the-art electrochemical performances with an integrated maximum energy density of 163 Wh kg^(-1) and an outstanding power density of 15,000 W kg^(-1).This elaborate work promotes better fundamental understanding about capacitive mechanism of PF_6~-ion and offers a rational dual-capacitive strategy for the design of advanced carbon cathodes.
基金supported by National Postdoctoral Program for Innovative Talents (BX201600192)the National Natural Science Foundation of China (51904342,21673298)+2 种基金China Postdoctoral Science Foundation (2017M6203552)National Key Research and Development Program of China (2017YFB0102000,2018YFB0104200)Hunan Provincial Science and Technology Plan (2017TP1001)。
文摘Carbon-based materials have attracted much interest as one of the promising anodes for sodium-ion batteries. However, low utilization of electrolyte and slow ion-transfer rate during electrochemical process hinder the further application of traditional bulk carbon. In order to enhance the diffusion kinetics and maintain the reversibility, hierarchical hollow carbon microbox was successfully prepared through a tunable bottom-up self-template routine for sodium-ion batteries. During annealing process, the morphology construction and activation happened synchronously. Based on that, a range of cross-linked porous nanosheet and hollow microbox were attained by manipulating reactant condition. The generation of texture and physical property are analyzed and are established linkages related to the electrochemical behavior. As results depicted in kinetic exploration and simulation based on cyclic voltammetry, the surfacecontrolled electrochemical behavior gradually turns to be the diffusion-controlled behavior as the hollow microbox evolves to porous nanosheet. The probable reason is that the rational microstructure/texture design leads to the accelerated diffusion kinetic procedure and the reduced concentration difference polarization. Sodium storage mechanism was deduced as reversible binding of Na-ions with local defects,including vacancies on sp2 graphitic layers, at the edges of flakes and other structural defects instead of intercalation. Bestowed by the morphology design, the broad pore width distribution, abundant defects/active sites and surface functionality, hollow microbox electrode delivers great electrochemical performances. This work is expected to propose a novel and effective strategy to prepare tunable hierarchical hollow carbon microbox and induce the fast kinetic of carbon anode material.
