Redox-active Mn is introduced into the B site of redox-stable perovskite niobate-titanate to improve the electrocatalytic activity of composite cathode in an oxide-ion-conducting solid oxide electrolyzer. The XRD and ...Redox-active Mn is introduced into the B site of redox-stable perovskite niobate-titanate to improve the electrocatalytic activity of composite cathode in an oxide-ion-conducting solid oxide electrolyzer. The XRD and XPS results reveal the successful partial replacement of Ti/Nb by Mn in the B site of niobate-titanate. The ionic conductivities of the Mndoped niobate-titanate are significantly improved by approximately 1 order of magnitude in reducing atmosphere and 0.5 order of magnitude in oxidizing atmosphere compared with bare niobate-titanate at 800 ℃. The current efficiency for Mn-doped niobate-titanate cathode is accordingly enhanced by ,-25% and 30% in contrast to the bare cathode with and without reducing gas flowing over the cathode under the applied voltage of 2.0 V at 800 ℃ in an oxide-ion-conducting solid oxide electrolyzer, respectively.展开更多
Making use of the relativistic BBGKY technique,the relativistic generalization of Landau collision integral is obtained.Furthermore,we calculate the relativistic hydrodynamic modes up to the second order in the hydrod...Making use of the relativistic BBGKY technique,the relativistic generalization of Landau collision integral is obtained.Furthermore,we calculate the relativistic hydrodynamic modes up to the second order in the hydrodynamic wave number.Combining Résibois' method,we present the first principle formula of the relativistic heat conductivity of Coulomb electronic plasmas for low-order corrections.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
Titanium niobium oxides emerge as promising anode materials with potential for applications in lithium ion batteries with high safety and high energy density.However,the innate low electronic conductivity of such a co...Titanium niobium oxides emerge as promising anode materials with potential for applications in lithium ion batteries with high safety and high energy density.However,the innate low electronic conductivity of such a composite oxide seriously limits its practical capacity,which becomes a serious concern especially when a high rate charge/discharge capability is expected.Here,using a modified template-assisted synthesis protocol,which features an in-situ entrapment of both titanium and niobium species during the formation of polymeric microsphere followed by a pyrolysis process,we succeed in preparing hollow microspheres of titanium niobium oxide with high efficiency in structural control.When used as an anode material,the structurally-controlled hollow sample delivers high reversible capacity(103.7 m A h g^(-1)at 50 C)and extraordinary cycling capability especially at high charge/discharge currents(164.7 m A h g^(-1)after 500 cycles at 10 C).展开更多
The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vana...The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vanadium redox flow batteries(VRFBs),a series of poly(fluorenyl ether)samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities(IECs)were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether)precursors.The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of micro-phase-separated morphologies and enhances anion conductivity.Moreover,the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes,thus complicating the relationship between the density of cationic group distribution and anion conductivity.The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms(DQA-PFE-C6)showed the highest anion conductivity.A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm^−2 at 250 mA cm^−2,which is significantly higher than a VRFB assembled with Nafion 212.Therefore,side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.展开更多
基金V. ACKNOWLEDGEMENTS This work was supported by the National Natural Science Foundation of China （No.21303037）, China Postdoctoral Science Foundation （No.2013M53150）, and tile Fundamental Research Funds for the Central Univcrsitics （No.2012HGZY0001）.
文摘Redox-active Mn is introduced into the B site of redox-stable perovskite niobate-titanate to improve the electrocatalytic activity of composite cathode in an oxide-ion-conducting solid oxide electrolyzer. The XRD and XPS results reveal the successful partial replacement of Ti/Nb by Mn in the B site of niobate-titanate. The ionic conductivities of the Mndoped niobate-titanate are significantly improved by approximately 1 order of magnitude in reducing atmosphere and 0.5 order of magnitude in oxidizing atmosphere compared with bare niobate-titanate at 800 ℃. The current efficiency for Mn-doped niobate-titanate cathode is accordingly enhanced by ,-25% and 30% in contrast to the bare cathode with and without reducing gas flowing over the cathode under the applied voltage of 2.0 V at 800 ℃ in an oxide-ion-conducting solid oxide electrolyzer, respectively.
文摘Making use of the relativistic BBGKY technique,the relativistic generalization of Landau collision integral is obtained.Furthermore,we calculate the relativistic hydrodynamic modes up to the second order in the hydrodynamic wave number.Combining Résibois' method,we present the first principle formula of the relativistic heat conductivity of Coulomb electronic plasmas for low-order corrections.
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 (51672282, 21373238)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA09010101)
文摘Titanium niobium oxides emerge as promising anode materials with potential for applications in lithium ion batteries with high safety and high energy density.However,the innate low electronic conductivity of such a composite oxide seriously limits its practical capacity,which becomes a serious concern especially when a high rate charge/discharge capability is expected.Here,using a modified template-assisted synthesis protocol,which features an in-situ entrapment of both titanium and niobium species during the formation of polymeric microsphere followed by a pyrolysis process,we succeed in preparing hollow microspheres of titanium niobium oxide with high efficiency in structural control.When used as an anode material,the structurally-controlled hollow sample delivers high reversible capacity(103.7 m A h g^(-1)at 50 C)and extraordinary cycling capability especially at high charge/discharge currents(164.7 m A h g^(-1)after 500 cycles at 10 C).
基金the National Natural Science Foundation of China(51873037 and 51503038)。
文摘The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vanadium redox flow batteries(VRFBs),a series of poly(fluorenyl ether)samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities(IECs)were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether)precursors.The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of micro-phase-separated morphologies and enhances anion conductivity.Moreover,the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes,thus complicating the relationship between the density of cationic group distribution and anion conductivity.The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms(DQA-PFE-C6)showed the highest anion conductivity.A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm^−2 at 250 mA cm^−2,which is significantly higher than a VRFB assembled with Nafion 212.Therefore,side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.
