Aqueous zinc-ion batteries(AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety,cost-effectiveness and environmental friendliness.However,issues such as dendrit...Aqueous zinc-ion batteries(AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety,cost-effectiveness and environmental friendliness.However,issues such as dendrite growth,hydrogen evolution reaction,and interfacial passivation occurring at the anode/electrolyte interface(AEI) have hindered their practical application.Constructing a stable AEI plays a key role in regulating zinc deposition and improving the cycle life of AZIBs.The fundamentals of AEI and the challenges faced by the Zn anode due to unstable interfaces are discussed.A comprehensive summary of electrolyte regulation strategies by electrolyte engineering to achieve a stable Zn anode is provided.The effectiveness evaluation techniques for stable AEI are also analyzed,including the interfacial chemistry and surface morphology evolution of the Zn anode.Finally,suggestions and perspectives for future research are offered about enabling a durable and stable AEI via electrolyte engineering,which may pave the way for developing high-performance AZIBs.展开更多
Solid-state Na metal batteries(SSNBs),known for its low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interf...Solid-state Na metal batteries(SSNBs),known for its low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of NaK alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the intimate contact of electrode-electrolyte interface.Additionally,the filling of SiO_(2)nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 h.The full cell coupled with Na_(3)V_(3)(PO_(4))_(2)cathodes had an initial discharge capacity of 106.8 mAh·g^(-1)with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1)even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.展开更多
Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombi...Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombic efficiency.To address the issues,cesium nitrate(CsNO3)is selected as the additive to modify the electrolyte for lithium secondary battery.Here we report electrochemical performance of lithium secondary battery with different concentration of CsNO3 as electrolyte additive.The study result demonstrates that Coulombic efficiency of Li–Cu cells and the lifetime of symmetric lithium cells contained CsNO3 additive are improved greatly.Li–Cu cell with 0.05 mol/L CsNO3 and 0.15 mol/L LiNO3 as electrolyte additive presents the best electrochemical performance,having the highest Coulombic efficiency of around 97%and the lowest interfacial resistance.With increasing the concentration of CsNO3 as electrolyte additive,the electrochemical performance of cells becomes poor.Meanwhile,the morphology of lithium deposited films with CsNO3-modified electrolyte become smoother and more uniform compared with the basic electrolyte.展开更多
A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fia...A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fiat anodes (Pb-0.8%Ag) used in industry. The anode corrosion rate was determined by anode actual current density and microstructure. The results show that the anodic oxygen evolution potential decreases first and then increases with the decrease of pore diameter. The anodic potential decreases to the lowest value of 1.729 V at the pore diameter of 1.25-1.60 mm. The porous anode can decrease its actual current density and thus decrease the anodic corrosion rate. When the pore diameter is 1.60-2.00 mm, the anodic relative corrosion rate reaches the lowest value of 52.1%.展开更多
In order to explain the phenomenon of negative capacitance(NC) in light emitting diodes LEDs, we present a new model based on local strong recombination in active region and firstly deduce the analytic expression of...In order to explain the phenomenon of negative capacitance(NC) in light emitting diodes LEDs, we present a new model based on local strong recombination in active region and firstly deduce the analytic expression of NO from continuity equation. The theoretical result indicates that the NC effect becomes stronger when the carrier recombination rate increases in a certain range,which is consistent with the experimental result. Accordingly,we confirm that the NO is caused by carrier recombination in active reaion instead of by other exterior factors.展开更多
Using the method of matrix diagonalization, we investigate an off-center D^- in a spherical quantum dot (QD) subjected to a parabolic potential confinement. We discuss the effect of the position of an impurity in th...Using the method of matrix diagonalization, we investigate an off-center D^- in a spherical quantum dot (QD) subjected to a parabolic potential confinement. We discuss the effect of the position of an impurity in the QD on the binding energy of the D system, Eurthermore, we compare a negatively charged donor D^- with a neutral donor DO confined by a spherical QD with a parabolic potentiM. The results have clearly demonstrate the so-called quantum size effect. The binding energy is dependent on the confining potential hw0 and the impurity ion distance D.展开更多
The formation and propagation of shocks and solitons are investigated in an unmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi m...The formation and propagation of shocks and solitons are investigated in an unmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi model. For this purpose, a deformed Korteweg-de Vries-Berger (dKdVB) equation is derived using the reductive perturbative technique for cold, adiabatic, and isothermal ions. Localized analytical solutions of dKdVB equation in planar geometry are obtained for dispersion as well as dissipation dominant cases. For nonplanar (cylindrical and spherical) geometry, time varying numerical shock wave solution of dKdVB equation is found. Its dispersion dominant case leading to the soliton solution is also discussed. The effect of ion temperature, positron concentration and dissipation is found significant on these nonlinear structures. The relevance of the results to the systems of scientific interest is pointed out.展开更多
As there are increasing numbers of small farms in Germany, it is necessary for them, to keep the workload as small as possible by enhancing the use of automatism. Important as those energetic-technical capabilities an...As there are increasing numbers of small farms in Germany, it is necessary for them, to keep the workload as small as possible by enhancing the use of automatism. Important as those energetic-technical capabilities and features in a modem dairy farm are, the final decision when using automatic machinery depends on the animal itself and its behavior. As a result, all animal-physiological criteria, animal protection and animal welfare have to be taken into consideration. Therefore tests have been done to investigate dairy cattle behavior on suddenly occurring energy failures, fluctuations or postponements due to a load management. The experiments have been taken in four different stables. In each stable, 12 "focus cows" have been selected. Their daily stress response was measured by a heart rate monitor and faecal cortisol metabolites. Video observation showed modifications in behavior, escape or avoidance reactions; pedometers recorded the movement activity. These scientific experiments will demonstrate cattle behavior in situations driven by a power load management, but no statistically significant effects on the usual daily routine are being expected.展开更多
The reliability of electric supply to consumers is one of the most important factors that determine the requirements imposed on modem utility companies. This paper presents the results of investigation by computer sof...The reliability of electric supply to consumers is one of the most important factors that determine the requirements imposed on modem utility companies. This paper presents the results of investigation by computer software of the overvoltages resulting from a ferroresonance conditions in MV networks at open phase operating condition with and without connection to earth on source and load sides of distribution transformer. This overvoltage may reach 4.2 pu on one of the HV side of transformer unswitched phases. The results of the study show that ferroresonance overvoltage may be controlled by replacing fuses with circuit breakers on HV side to ensure switching-off all phases. Insertion of resistor or reactor in the neutral of source and loadsides of the transformer with 5% active load will help in suppressing overvoltages.展开更多
Lithium (Li) metal is considered as the ultimate anode choice for developing next-generation high-energy batteries. However, the poor tolerance against moist air and the unstable solid electrolyte interphases (SEI) in...Lithium (Li) metal is considered as the ultimate anode choice for developing next-generation high-energy batteries. However, the poor tolerance against moist air and the unstable solid electrolyte interphases (SEI) induced by the intrinsic high reactivity of lithium bring series of obstacles such as the rigorous operating condition, the poor electrochemical performance, and safety anxiety of the cell, which to a large extent hinder the commercial utilization of Li metal anode. Here, an effective encapsulation strategy was reported via a facile drop-casting and a following heat-assisted cross-linking process. Benefiting from the inherent hydrophobicity and the compact micro-structure of the cross-linked poly(vinylidene-co-hex afluoropropylene) (PVDF–HFP), the as-encapsulated Li metal exhibited prominent stability toward moisture, as well corroborated by the evaluations both under the humid air at 25 °C with 30% relative humidity (RH) and pure water. Moreover, the encapsulated Li metal anode exhibits a decent electrochemical performance without substantially increasing the cell polarization due to the uniform and unblocked ion channels, which originally comes from the superior affinity of the PVDF–HFP polymer toward nonaqueous electrolyte. This work demonstrates a novel and valid encapsulation strategy for humiditysensitive alkali metal electrodes, aiming to pave the way for the large-scale and low-cost deployment of the alkali metal-based high-energy-density batteries.展开更多
Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reaction...Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers.Herein,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ.This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration electrolytes.Thus,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.展开更多
Aqueous zinc-ion batteries(ZIBs)are perceived as one of the most upcoming grid-scale storage systems.However,the issues of electrode dissolution,dendrite formation,and corrosion in traditional liquid electrolytes have...Aqueous zinc-ion batteries(ZIBs)are perceived as one of the most upcoming grid-scale storage systems.However,the issues of electrode dissolution,dendrite formation,and corrosion in traditional liquid electrolytes have plagued its progress.In this work,Zn dendrite growth and side reactions are effectively suppressed by a highly-confined tannic acid(TA)modified sodium alginate(SA)composite gel electrolyte(TA-SA).The ion-confinement effect is enhanced by divalent zinc ions coordinated with carboxyl groups and chelated with phenolic hydroxyl groups,thus guiding and regulating Zn deposition to achieve steady zinc plating/stripping behavior.As a consequence,the Zn/TA-SA/NH_(4)V_(4)O_(10) full cells deliver a high specific capacity of 238.6 mAh g^(-1) and maintain 94.51%over 900 cycles at 2 A g^(-1).Notably,after resting over 5 d,the capacity can be stabilized with a capacity retention of 97.25%after 200 cycles at 2 A g^(-1).This highlyconfined and hydrogen bond-strengthened gel electrolyte may provide an effective strategy for the future development of quasi-solid-state metal batteries.展开更多
Development of high-voltage electrolytes with non-flammability is significantly important for future energy storage devices.Aqueous electrolytes are inherently non-flammable,easy to handle,and their electrochemical st...Development of high-voltage electrolytes with non-flammability is significantly important for future energy storage devices.Aqueous electrolytes are inherently non-flammable,easy to handle,and their electrochemical stability windows(ESWs)can be considerably expanded by increasing electrolyte concentrations.However,further breakthroughs of their ESWs encounter bottlenecks because of the limited salt solubility,leading to that most of the high-energy anode materials can hardly function reversibly in aqueous electrolytes.Here,by introducing a non-flammable ionic liquid as co-solvent in a lithium salt/water system,we develop a"water in salt/ionic liquid"(WiSIL)electrolyte with extremely low water content.In such WiSIL electrolyte,commercial niobium pentoxide(Nb2O5)material can operate at a low potential(-1.6 V versus Ag/AgCl)and contribute its full capacity.Consequently,the resultant Nb2O5-based aqueous lithium-ion capacitor is able to operate at a high voltage of 2.8 V along with long cycling stability over 3000 cycles,and displays comparable energy and power performance(51.9 Wh kg^-1 at 0.37 kW kg^-1 and 16.4 Wh kg^-1 at 4.9 kW kg^-1)to those using non-aqueous electrolytes but with improved safety performance and manufacturing efficiency.展开更多
The unstable interfaces between a SnO_(2)anode and an electrolyte in a Li-ion battery dramatically impair the reversibility and cycling stability of lithiation and delithiation,resulting in low roundtrip Coulombic eff...The unstable interfaces between a SnO_(2)anode and an electrolyte in a Li-ion battery dramatically impair the reversibility and cycling stability of lithiation and delithiation,resulting in low roundtrip Coulombic efficiency(CE)and fast capacity decay of SnO_(2)-based anode materials.Herein,a simple strategy of modifying the solid electrolyte interphase(SEI)is developed to enhance the interfacial stability and lithium storage reversibility of SnO_(2)by compositing it with graphite(G)and an inorganic component of the SEI,such as Li_(2)CO_(3)or LiF,which results in the SnO_(2)-Li_(2)CO_(3)/G and SnO_(2)-LiF/G composite anodes with high CEs,large capacities and long cycle lives.Specifically,the SnO_(2)-Li_(2)CO_(3)/G composite anode exhibits an average initial CE of 79.6%,a stable reversible capacity of 927.5 mA hg^(-1)at a current rate of 0.2 A g^(-1),and a charge capacity over 1200 mA hg^(-1)with a CE>99%after 900 cycles at a higher current rate of 1 A g^(-1).It is revealed that Li_(2)CO_(3)induces the formation of a dense and stable SEI on SnO_(2)grains and inhibits the coarsening of nanosized Sn particles generated from the dealloying reaction in the SnO_(2)-Li_(2)CO_(3)/G electrode.Moreover,the CE and cycling stability of other alloying-type(Si)and conversion reaction(MnO_(2)and Fe_(3)O_(4))anodes can also be greatly promoted by simply milling with Li_(2)CO_(3).Thus,a universal and simple strategy is developed to achieve highly reversible and stable electrodes for large-capacity lithium storage.展开更多
Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining p...Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining pair production rate is presented,and approximate analytical expressions are given both for the low frequency strong field regime and the high frequency weak field regime.We found that for an elliptically polarized field,the electron-positron pair production rate decrease when the elliptic eccentricity increase in the high frequency weak field regime,however,in the low frequency strong field regime,there is almost the same electron-positron pair production rate as in the constant electric field case.展开更多
Zn-air batteries are promising energy storage and conversion systems to replace the conventional lithiumbased ones.However,their applications have been greatly hindered by the formation of Zn dendrites and ZnO passiva...Zn-air batteries are promising energy storage and conversion systems to replace the conventional lithiumbased ones.However,their applications have been greatly hindered by the formation of Zn dendrites and ZnO passivation layer on the Zn anodes.Herein,we report the fabrication of an artificial protective layer comprised of N-doped threedimensional hollow porous multi-nanochannel carbon fiber with well-dispersed TiO_(2) nanoparticles(HMCNF).The incorporated TiO;nanoparticles and N dopants improve the ion flux distribution and promote the surface adsorption,facilitating the interfacial pseudocapacitive behaviors during Zn deposition.The hierarchical architecture also induces homogenous electric field distribution at the anode/electrolyte interface.Accordingly,the deposition behavior of Zn is regulated,giving rise to enhanced utilization and rechargeability of Zn.When integrated in alkaline Zn-air batteries,the HMCNF-coated Zn anodes exhibit improved electrochemical performances relative to those with the bare Zn anodes,demonstrating a versatile strategy to boost energy storage of metal anodes through optimizing surface adsorption properties.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 52377222)the Natural Science Foundation of Hunan Province, China (Nos. 2023JJ20064, 2023JJ40759)。
文摘Aqueous zinc-ion batteries(AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety,cost-effectiveness and environmental friendliness.However,issues such as dendrite growth,hydrogen evolution reaction,and interfacial passivation occurring at the anode/electrolyte interface(AEI) have hindered their practical application.Constructing a stable AEI plays a key role in regulating zinc deposition and improving the cycle life of AZIBs.The fundamentals of AEI and the challenges faced by the Zn anode due to unstable interfaces are discussed.A comprehensive summary of electrolyte regulation strategies by electrolyte engineering to achieve a stable Zn anode is provided.The effectiveness evaluation techniques for stable AEI are also analyzed,including the interfacial chemistry and surface morphology evolution of the Zn anode.Finally,suggestions and perspectives for future research are offered about enabling a durable and stable AEI via electrolyte engineering,which may pave the way for developing high-performance AZIBs.
基金National Natural Science Foundation of China(52073253)。
文摘Solid-state Na metal batteries(SSNBs),known for its low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of NaK alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the intimate contact of electrode-electrolyte interface.Additionally,the filling of SiO_(2)nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 h.The full cell coupled with Na_(3)V_(3)(PO_(4))_(2)cathodes had an initial discharge capacity of 106.8 mAh·g^(-1)with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1)even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.
基金Project(2016YFB0300801)supported by the National Key Research and Development Program of ChinaProject(2012CB619502)supported by the National Basic Research Program of China
文摘Lithium metal is one of the most promising anode materials for rechargeable battery with high energy density,but its practical use is still hindered by two main problems,namely,lithium dendrite growth and low Coulombic efficiency.To address the issues,cesium nitrate(CsNO3)is selected as the additive to modify the electrolyte for lithium secondary battery.Here we report electrochemical performance of lithium secondary battery with different concentration of CsNO3 as electrolyte additive.The study result demonstrates that Coulombic efficiency of Li–Cu cells and the lifetime of symmetric lithium cells contained CsNO3 additive are improved greatly.Li–Cu cell with 0.05 mol/L CsNO3 and 0.15 mol/L LiNO3 as electrolyte additive presents the best electrochemical performance,having the highest Coulombic efficiency of around 97%and the lowest interfacial resistance.With increasing the concentration of CsNO3 as electrolyte additive,the electrochemical performance of cells becomes poor.Meanwhile,the morphology of lithium deposited films with CsNO3-modified electrolyte become smoother and more uniform compared with the basic electrolyte.
基金Project(2007SK2009) supported by the Science and Technology Research Project of Hunan Province, China
文摘A new type of lead-based porous anode in zinc electrowinning was prepared by negative pressure infiltration. The anodic polarization potential and corrosion rate were studied and compared with those of traditional fiat anodes (Pb-0.8%Ag) used in industry. The anode corrosion rate was determined by anode actual current density and microstructure. The results show that the anodic oxygen evolution potential decreases first and then increases with the decrease of pore diameter. The anodic potential decreases to the lowest value of 1.729 V at the pore diameter of 1.25-1.60 mm. The porous anode can decrease its actual current density and thus decrease the anodic corrosion rate. When the pore diameter is 1.60-2.00 mm, the anodic relative corrosion rate reaches the lowest value of 52.1%.
基金This work was supported by the National Nature Science Foun-dation (Grant No.DMR-60376027) .
文摘In order to explain the phenomenon of negative capacitance(NC) in light emitting diodes LEDs, we present a new model based on local strong recombination in active region and firstly deduce the analytic expression of NO from continuity equation. The theoretical result indicates that the NC effect becomes stronger when the carrier recombination rate increases in a certain range,which is consistent with the experimental result. Accordingly,we confirm that the NO is caused by carrier recombination in active reaion instead of by other exterior factors.
基金supported by the National Natural Science Foundation of China under Grant No.10775035
文摘Using the method of matrix diagonalization, we investigate an off-center D^- in a spherical quantum dot (QD) subjected to a parabolic potential confinement. We discuss the effect of the position of an impurity in the QD on the binding energy of the D system, Eurthermore, we compare a negatively charged donor D^- with a neutral donor DO confined by a spherical QD with a parabolic potentiM. The results have clearly demonstrate the so-called quantum size effect. The binding energy is dependent on the confining potential hw0 and the impurity ion distance D.
基金Supported by Quaid-i-Azam University Research Fund,URF Project No.URF/(2007-2009)
文摘The formation and propagation of shocks and solitons are investigated in an unmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi model. For this purpose, a deformed Korteweg-de Vries-Berger (dKdVB) equation is derived using the reductive perturbative technique for cold, adiabatic, and isothermal ions. Localized analytical solutions of dKdVB equation in planar geometry are obtained for dispersion as well as dissipation dominant cases. For nonplanar (cylindrical and spherical) geometry, time varying numerical shock wave solution of dKdVB equation is found. Its dispersion dominant case leading to the soliton solution is also discussed. The effect of ion temperature, positron concentration and dissipation is found significant on these nonlinear structures. The relevance of the results to the systems of scientific interest is pointed out.
文摘As there are increasing numbers of small farms in Germany, it is necessary for them, to keep the workload as small as possible by enhancing the use of automatism. Important as those energetic-technical capabilities and features in a modem dairy farm are, the final decision when using automatic machinery depends on the animal itself and its behavior. As a result, all animal-physiological criteria, animal protection and animal welfare have to be taken into consideration. Therefore tests have been done to investigate dairy cattle behavior on suddenly occurring energy failures, fluctuations or postponements due to a load management. The experiments have been taken in four different stables. In each stable, 12 "focus cows" have been selected. Their daily stress response was measured by a heart rate monitor and faecal cortisol metabolites. Video observation showed modifications in behavior, escape or avoidance reactions; pedometers recorded the movement activity. These scientific experiments will demonstrate cattle behavior in situations driven by a power load management, but no statistically significant effects on the usual daily routine are being expected.
文摘The reliability of electric supply to consumers is one of the most important factors that determine the requirements imposed on modem utility companies. This paper presents the results of investigation by computer software of the overvoltages resulting from a ferroresonance conditions in MV networks at open phase operating condition with and without connection to earth on source and load sides of distribution transformer. This overvoltage may reach 4.2 pu on one of the HV side of transformer unswitched phases. The results of the study show that ferroresonance overvoltage may be controlled by replacing fuses with circuit breakers on HV side to ensure switching-off all phases. Insertion of resistor or reactor in the neutral of source and loadsides of the transformer with 5% active load will help in suppressing overvoltages.
基金This work was supported by National Key Research and Development Program(2016YFA0202500)National Natural Science Foundation of China(21776019)Beijing Natural Science Foundation(L182021).
文摘Lithium (Li) metal is considered as the ultimate anode choice for developing next-generation high-energy batteries. However, the poor tolerance against moist air and the unstable solid electrolyte interphases (SEI) induced by the intrinsic high reactivity of lithium bring series of obstacles such as the rigorous operating condition, the poor electrochemical performance, and safety anxiety of the cell, which to a large extent hinder the commercial utilization of Li metal anode. Here, an effective encapsulation strategy was reported via a facile drop-casting and a following heat-assisted cross-linking process. Benefiting from the inherent hydrophobicity and the compact micro-structure of the cross-linked poly(vinylidene-co-hex afluoropropylene) (PVDF–HFP), the as-encapsulated Li metal exhibited prominent stability toward moisture, as well corroborated by the evaluations both under the humid air at 25 °C with 30% relative humidity (RH) and pure water. Moreover, the encapsulated Li metal anode exhibits a decent electrochemical performance without substantially increasing the cell polarization due to the uniform and unblocked ion channels, which originally comes from the superior affinity of the PVDF–HFP polymer toward nonaqueous electrolyte. This work demonstrates a novel and valid encapsulation strategy for humiditysensitive alkali metal electrodes, aiming to pave the way for the large-scale and low-cost deployment of the alkali metal-based high-energy-density batteries.
基金supported by the National Natural Science Foundation of China(91963118 and 52173246)Science Technology Program of Jilin Province(20200201066JC)the 111 Project(B13013)。
文摘Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers.Herein,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ.This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration electrolytes.Thus,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.
基金supported by the National Natural Science Foundation of China(51972346,51932011)the Hunan Natural Science Fund for Distinguished Young Scholar(2021JJ10064)+1 种基金the Program of Youth Talent Support for Hunan Province(2020RC3011)the Innovation-Driven Project of Centra South University(2020CX024)。
文摘Aqueous zinc-ion batteries(ZIBs)are perceived as one of the most upcoming grid-scale storage systems.However,the issues of electrode dissolution,dendrite formation,and corrosion in traditional liquid electrolytes have plagued its progress.In this work,Zn dendrite growth and side reactions are effectively suppressed by a highly-confined tannic acid(TA)modified sodium alginate(SA)composite gel electrolyte(TA-SA).The ion-confinement effect is enhanced by divalent zinc ions coordinated with carboxyl groups and chelated with phenolic hydroxyl groups,thus guiding and regulating Zn deposition to achieve steady zinc plating/stripping behavior.As a consequence,the Zn/TA-SA/NH_(4)V_(4)O_(10) full cells deliver a high specific capacity of 238.6 mAh g^(-1) and maintain 94.51%over 900 cycles at 2 A g^(-1).Notably,after resting over 5 d,the capacity can be stabilized with a capacity retention of 97.25%after 200 cycles at 2 A g^(-1).This highlyconfined and hydrogen bond-strengthened gel electrolyte may provide an effective strategy for the future development of quasi-solid-state metal batteries.
基金supported by the National Natural Science Foundations of China(21573265 and 21673263)the Zhaoqing Municipal Science and Technology Bureau(2019K038)+2 种基金the Key Cultivation Projects of the Institute in 13th Five-Yearthe Instruments Function Development&Technology Innovation Project of Chinese Academy of Sciences(2020g105)the Western Young Scholars Foundations of Chinese Academy of Sciences。
文摘Development of high-voltage electrolytes with non-flammability is significantly important for future energy storage devices.Aqueous electrolytes are inherently non-flammable,easy to handle,and their electrochemical stability windows(ESWs)can be considerably expanded by increasing electrolyte concentrations.However,further breakthroughs of their ESWs encounter bottlenecks because of the limited salt solubility,leading to that most of the high-energy anode materials can hardly function reversibly in aqueous electrolytes.Here,by introducing a non-flammable ionic liquid as co-solvent in a lithium salt/water system,we develop a"water in salt/ionic liquid"(WiSIL)electrolyte with extremely low water content.In such WiSIL electrolyte,commercial niobium pentoxide(Nb2O5)material can operate at a low potential(-1.6 V versus Ag/AgCl)and contribute its full capacity.Consequently,the resultant Nb2O5-based aqueous lithium-ion capacitor is able to operate at a high voltage of 2.8 V along with long cycling stability over 3000 cycles,and displays comparable energy and power performance(51.9 Wh kg^-1 at 0.37 kW kg^-1 and 16.4 Wh kg^-1 at 4.9 kW kg^-1)to those using non-aqueous electrolytes but with improved safety performance and manufacturing efficiency.
基金the National Natural Science Foundation of China(52071144,51621001,51822104 and 51831009)。
文摘The unstable interfaces between a SnO_(2)anode and an electrolyte in a Li-ion battery dramatically impair the reversibility and cycling stability of lithiation and delithiation,resulting in low roundtrip Coulombic efficiency(CE)and fast capacity decay of SnO_(2)-based anode materials.Herein,a simple strategy of modifying the solid electrolyte interphase(SEI)is developed to enhance the interfacial stability and lithium storage reversibility of SnO_(2)by compositing it with graphite(G)and an inorganic component of the SEI,such as Li_(2)CO_(3)or LiF,which results in the SnO_(2)-Li_(2)CO_(3)/G and SnO_(2)-LiF/G composite anodes with high CEs,large capacities and long cycle lives.Specifically,the SnO_(2)-Li_(2)CO_(3)/G composite anode exhibits an average initial CE of 79.6%,a stable reversible capacity of 927.5 mA hg^(-1)at a current rate of 0.2 A g^(-1),and a charge capacity over 1200 mA hg^(-1)with a CE>99%after 900 cycles at a higher current rate of 1 A g^(-1).It is revealed that Li_(2)CO_(3)induces the formation of a dense and stable SEI on SnO_(2)grains and inhibits the coarsening of nanosized Sn particles generated from the dealloying reaction in the SnO_(2)-Li_(2)CO_(3)/G electrode.Moreover,the CE and cycling stability of other alloying-type(Si)and conversion reaction(MnO_(2)and Fe_(3)O_(4))anodes can also be greatly promoted by simply milling with Li_(2)CO_(3).Thus,a universal and simple strategy is developed to achieve highly reversible and stable electrodes for large-capacity lithium storage.
基金Supported by the National Natural Science Foundation of China (NNSFC) under the grant Nos. 10875015,11175023,10965006,11165014partially by the Fundamental Research Funds for the Central Universities (FRFCU)
文摘Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining pair production rate is presented,and approximate analytical expressions are given both for the low frequency strong field regime and the high frequency weak field regime.We found that for an elliptically polarized field,the electron-positron pair production rate decrease when the elliptic eccentricity increase in the high frequency weak field regime,however,in the low frequency strong field regime,there is almost the same electron-positron pair production rate as in the constant electric field case.
基金supported by the National Natural Science Foundation of China(52002060)Shanghai Sailing Program(20YF1400600)the Fundamental Research Funds for the Central Universities(2232021D-06)。
文摘Zn-air batteries are promising energy storage and conversion systems to replace the conventional lithiumbased ones.However,their applications have been greatly hindered by the formation of Zn dendrites and ZnO passivation layer on the Zn anodes.Herein,we report the fabrication of an artificial protective layer comprised of N-doped threedimensional hollow porous multi-nanochannel carbon fiber with well-dispersed TiO_(2) nanoparticles(HMCNF).The incorporated TiO;nanoparticles and N dopants improve the ion flux distribution and promote the surface adsorption,facilitating the interfacial pseudocapacitive behaviors during Zn deposition.The hierarchical architecture also induces homogenous electric field distribution at the anode/electrolyte interface.Accordingly,the deposition behavior of Zn is regulated,giving rise to enhanced utilization and rechargeability of Zn.When integrated in alkaline Zn-air batteries,the HMCNF-coated Zn anodes exhibit improved electrochemical performances relative to those with the bare Zn anodes,demonstrating a versatile strategy to boost energy storage of metal anodes through optimizing surface adsorption properties.