Lithium-rich layered oxides (LLOs) are increasingly recognized as promising cathode materials for nextgeneration high-energy-density lithium-ion batteries (LIBs).However,they suffer from voltage decay and low initial ...Lithium-rich layered oxides (LLOs) are increasingly recognized as promising cathode materials for nextgeneration high-energy-density lithium-ion batteries (LIBs).However,they suffer from voltage decay and low initial Coulombic efficiency (ICE) due to severe structural degradation caused by irreversible O release.Herein,we introduce a three-in-one strategy of increasing Ni and Mn content,along with Li/Ni disordering and TM–O covalency regulation to boost cationic and anionic redox activity simultaneously and thus enhance the electrochemical activity of LLOs.The target material,Li_(1.2)Ni_(0.168)Mn_(0.558)Co_(0.074)O_(2)(L1),exhibits an improved ICE of 87.2%and specific capacity of 293.2 mA h g^(-1)and minimal voltage decay of less than 0.53 m V cycle-1over 300 cycles at 1C,compared to Li_(1.2)Ni_(0.13)Mn_(0.54)Co_(0.13)O_(2)(Ls)(274.4 mA h g^(-1)for initial capacity,73.8%for ICE and voltage decay of 0.84 mV/cycle over 300 cycles at 1C).Theoretical calculations reveal that the density of states (DOS) area near the Fermi energy level for L1 is larger than that of Ls,indicating higher anionic and cationic redox reactivity than Ls.Moreover,L1 exhibits increased O-vacancy formation energy due to higher Li/Ni disordering of 4.76%(quantified by X-ray diffraction Rietveld refinement) and enhanced TM–O covalency,making lattice O release more difficult and thus improving electrochemical stability.The increased Li/Ni disordering also leads to more Ni^(2+)presence in the Li layer,which acts as a pillar during Li+de-embedding,improving structural stability.This research not only presents a viable approach to designing low-Co LLOs with enhanced capacity and ICE but also contributes significantly to the fundamental understanding of structural regulation in high-performance LIB cathodes.展开更多
Li-rich layered transition metal oxides are one of the most promising cathode materials for their high energy density.However,the cathodes usually suffer from severe potential dropping and capacity fading during cycli...Li-rich layered transition metal oxides are one of the most promising cathode materials for their high energy density.However,the cathodes usually suffer from severe potential dropping and capacity fading during cycling,which are associated with the surface oxygen release and accompanied by cation densification and structural collapse.Herein,an integrative approach of simultaneous constructing uniform 3d Fe-ion doping in the transition metal layer and Li-rich Li_(5)FeO_(4) shell to grab the oxygen and prevent interfacial side reactions is proposed.The introduction of Fe induces higher redox potential and stronger 3 d Fe-O_(2)p covalent bond,triggering reversible anionic redox via a reductive coupling mechanism.And the delithiated product of Li-rich Li_(5)FeO_(4) not only acts as a protective layer alleviating the side reactions but also enhances the surface kinetic property.With the benefit of promoted reversibility of oxygen redox and enhanced surface stability,the cathode exhibits high reversible capacity and superior cycle performance.Density function theory calculation indicates that the O_(2)p non-bonding state in the cathode incorporated with Fe sits at a lower energy band,resulting in higher energy storage voltage and improved oxygen stability.Consequently,the modified cathode exhibits a discharge specific capacity of 307 m A h g^(-1)(1 C=250 m A g^(-1)),coulombic efficiency of 82.09%in the initial cycle at 0.1 C and 88.34%capacity retention after 100 cycles at 1 C.The work illustrates a strategy that could simultaneously enhance oxygen redox reversibility and interface stability by constructing lattice bond coordination and delithiation induced protective layer to develop Li-rich materials with high reversible capacity and long lifespan.展开更多
Two-dimensional conductive metal-organic frameworks(2D c-MOFs)with high flexibility in structure design and functionalization have inspired numerous research interests as promising multifunctional materials due to the...Two-dimensional conductive metal-organic frameworks(2D c-MOFs)with high flexibility in structure design and functionalization have inspired numerous research interests as promising multifunctional materials due to their porous structure,high conductivity,and rich redox active sites.This review offers a concise overview of 2D c-MOF syntheses and their applications in rechargeable batteries.The electron transport mechanism of 2D c-MOFs will be briefly introduced first.Then we discuss the designs and syntheses of 2D c-MOFs,emphasizing the conjugate structure for high conductivity and the redox activity for efficient energy storage.The electrochemical behaviors of the 2D c-MOFs in different rechargeable battery systems are summarized with attention to their structure-performance correlations and storage mechanism.Particular attention is paid to the significant applied potential of 2D c-MOFs in the Na-ion batteries(NIBs)and Kion batteries(KIBs),which are more sustainable battery chemistries but are plagued by the dissatisfactory battery performances due to the large size of the Na^(+)and K^(+).The challenges and opportunities regarding their efficient synthesis and rechargeable battery applications are also discussed.We expect this review will spark new endeavors to promote the further development of 2D c-MOFs for advanced rechargeable batteries.展开更多
The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using poly...The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using polychelates,PAA-Co X(X:3,5,7,and 10)where X represents the doping fraction(w/w)of Co in PAA.All polymer metal electrolytes were showed excellent bending-stretching properties,thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15×10^(-4) S cm^(-1).Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes.The electric double-layer capacitor(EDLC)and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g^(-1) with a device of PAA-Co7,which is at least 15 times enhancement compared to the device of pristine PAA.The PAA-Co7 device also provided energy density of 21.25 Wh kg^(-1) at a power density of 117.69 W kg^(-1).A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge-discharge cycles and the maintained 90%of its initial performance.In addition,the supercapacitor with a dimension of 1.5 cm×3 cm containing PAA-Co7 successfully operated the red-blue-green(RGB)LED light.展开更多
Due to the diversity and feasibility of structural modification for organic molecules,organic-based redox flow batteries(ORFBs)have been widely investigated,especially in aqueous solution under neutral circumstance.In...Due to the diversity and feasibility of structural modification for organic molecules,organic-based redox flow batteries(ORFBs)have been widely investigated,especially in aqueous solution under neutral circumstance.In this work,a symmetric aqueous redox flow battery(SARFB)was rationally designed by employing a bipolar redox active molecule(N,N’-dimethyl-4,4-bipyridinium diiodide,MVI2)as both cathode and anode materials and combining with an anion exchange membrane.For one MVI2 flow battery,MV2+/MV·+and I-/I3-serve as the redox couples of anode and cathode,respectively.The MVI2 battery with a working voltage of 1.02 V exhibited a high voltage efficiency of 90.30%and energy efficiency of 89.44%after 450 cycles,and crossover problem was prohibited.The comparable conductivity of MVI2 water solution enabled to construct a battery even without using supporting electrolyte.Besides,the bipolar character of MVI2 battery with/without supporting electrolyte was investigated in the voltage range between-1.2 V and 1.2 V,showing excellent stable cycling stability during the polarity-reversal test.展开更多
Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through s...Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through synergistic anionic and cationic redox reactions.However,these materials face challenges including oxygen release-induced structural degradation and consequent capacity fading.To address these issues,strategies such as surface modification and bulk phase engineering have been explored.In this study,we developed a facile and cost-effective quenching approach that simultaneously modifies both surface and bulk characteristics.Multi-scale characterization and computational analysis reveal that rapid cooling partially preserves the high-temperature disordered phase in the bulk structure,thereby enhancing the structural stability.Concurrently,Li^(+)/H^(+)exchange at the surface forms a robust rock-salt/spinel passivation layer,effectively suppressing oxygen evolution and mitigating interfacial side reactions.This dual modification strategy demonstrates a synergistic stabilization effect.The enhanced oxygen redox activity coexists with the improved structural integrity,leading to superior electrochemical performance.The optimized cathode delivers an initial discharge capacity approaching 307.14 mAh/g at 0.1 C and remarkable cycling stability with 94.12%capacity retention after 200 cycles at 1 C.This study presents a straightforward and economical strategy for concurrent surface–bulk modification,offering valuable insights for designing high-capacity LRM cathodes with extended cycle life.展开更多
The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,thes...The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,these organic molecules often exhibit sluggish reaction kinetics and unsatisfactory utilization of active sites,presenting significant challenges for their practical deployment as electrode materials in aqueous batteries.In this study,we have synthesized a novel organic compound(PTPZ),comprised of a centrally symmetric and fully ladder-type structure,tailored for aqueous proton storage.This unique configuration imparts the PTPZ molecule with high electron delocalization and enhanced structural stability.As an electrode material,PTPZ demonstrates a substantial proton-storage capacity of 311.9mAh g^(-1),with an active group utilization efficiency of up to 89% facilitated by an 8-electron transfer process,while maintaining a capacity retention of 92.89% after 8000 chargingdischarging cycles.Furthermore,in-situ monitoring technologies and various theoretical analyses have pinpointed the associated electrochemical processes of the PTPZ electrode,revealing exceptional redox activity,rapid proton diffusion,and efficient charge transfer.These attributes confer a significant competitive advantage to PTPZ as an anode material for high-performance proton storage devices.Consequently,this work contributes to the rational design of organic electrode materials for the advancement of rechargeable aqueous batteries.展开更多
α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the wi...α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.展开更多
The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide...The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.展开更多
Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reduc...Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria（SRB） on mercury（Hg） methylation at sediment–water interfaces. Concentrations of dissolved methyl mercury（DMe Hg） in the overlying water of the control cores with bioactivity maintained（BAC） and cores with only sulfate-reducing bacteria inhibited（SRBI） and bacteria fully inhibited（BACI） were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMe Hg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations（r =- 0.5311 and r =- 0.4977 for BAC and SRBI, respectively）. The water DMe Hg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment–water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster（hgc AB）, besides SRB,causing Hg methylation in the sediment–water system.展开更多
An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of th...An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.展开更多
Lithium rich layered oxide(LRLO) has been considered as one of the promising cathodes for lithium-ion batteries(LIBs). The high voltage and large capacity of LRLO depend on Li2MnO_(3)phase. To ameliorate the electroch...Lithium rich layered oxide(LRLO) has been considered as one of the promising cathodes for lithium-ion batteries(LIBs). The high voltage and large capacity of LRLO depend on Li2MnO_(3)phase. To ameliorate the electrochemical performance of Li2MnO_(3), also written as Li(Li1/3Mn2/3)O_(2), we propose a strategy to substitute Mn4+and Li+in Mn/Li transition metal layer with Ti4+, which can stabilize the structure of Li2MnO_(3)by inhibiting the excessive oxidation of O_(2)-above 4.5 V. More significantly, the unequal-valent substitution brings about the emergence of interlayer Li vacancies, which can promote the Li-ion diffusion based on the enlarged interlayer and increase the capacity by activating the Mn3+/4+redox. We designed Li0.7[Li1/3Mn2/3]0.7Ti0.3O_(2)with high interlayer Li vacancies, which presents a high capacity(290 m Ah/g at 10 m A/g) and stable cycling performance(84% over 60 cycles at 50 m A/g). We predict that this strategy will be helpful to further improve the electrochemical performance of LRLOs.展开更多
Seven square planar bis（o-diiminobenzosemiquinonato）nickel（II） complexes, [Ni（o-C6H4（NH）（NAr））2] （Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3）, [Ni（o-4,5-F2-C6H2（NH）（NPh））2] （4）, and [Ni（o-4,5-CIz-C6H2...Seven square planar bis（o-diiminobenzosemiquinonato）nickel（II） complexes, [Ni（o-C6H4（NH）（NAr））2] （Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3）, [Ni（o-4,5-F2-C6H2（NH）（NPh））2] （4）, and [Ni（o-4,5-CIz-C6H2（NH）（NAr））2] （Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7）, have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies （1 and 7）. The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n＋. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni（o-C6Ha（NH）（NPh））2] （8） and [Ni（o-3,5-Butz-C6Hz（NH）2）2] （9）, are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na（THF）3][I] and [Na（THF）3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill（lL-1 ）（IL2-）]1- and [Ni1]（1L2 ）212-, which are in line with those of [9]n （n = 1-, 2-） suggested by spectroelectrochemical study.展开更多
Given post-operative aseptic loosening in orthopedic disease treatment,osteointegration occurs at the bone-implant interface as a holistic process,including immunoregulation(e.g.,macrophage polarization),angiogenesis ...Given post-operative aseptic loosening in orthopedic disease treatment,osteointegration occurs at the bone-implant interface as a holistic process,including immunoregulation(e.g.,macrophage polarization),angiogenesis and osteogenesis in sequence.In order to achieve early rapid and satisfactory osseointegration,different nano-shaped(nanocone,nanopolyhedron and nanoflower abbr.NC,NP&NF)cerium oxide(CeO_(2-x))coatings,endowed with“nanozyme-like”activities for multiple free radical elimination and osteoimmunology regulation,were hydrothermally synthesized on titanium alloy(TC4).In vitro cell experiments showed that nano-CeO_(2-x) coated TC4 not only induced polarization of RAW264.7 cells toward M2 phenotype,but also promoted angiogenesis and vascularization of endothelial cells along with differentiation and mineralization of osteogenic precursor cells.Improvements in M2-polarized macrophage,angiogenesis,and bone regeneration were further confirmed in a rat femoral condyle model.Among the above three nano-morphologies,NF exhibited the best osseoinetegration.RNA sequencing and mechanism exploration suggested that the inhibition of PI3K-AKT signaling pathway was essential for immunomodulatory capacity of NF.In conclusion,it provided promising insights into the immunomodulatory exploitation of orthopedic implants.展开更多
基金National Natural Science Foundation of China (No.52202046)Natural Science Foundation of Shaanxi Province (No.2021JQ-034)。
文摘Lithium-rich layered oxides (LLOs) are increasingly recognized as promising cathode materials for nextgeneration high-energy-density lithium-ion batteries (LIBs).However,they suffer from voltage decay and low initial Coulombic efficiency (ICE) due to severe structural degradation caused by irreversible O release.Herein,we introduce a three-in-one strategy of increasing Ni and Mn content,along with Li/Ni disordering and TM–O covalency regulation to boost cationic and anionic redox activity simultaneously and thus enhance the electrochemical activity of LLOs.The target material,Li_(1.2)Ni_(0.168)Mn_(0.558)Co_(0.074)O_(2)(L1),exhibits an improved ICE of 87.2%and specific capacity of 293.2 mA h g^(-1)and minimal voltage decay of less than 0.53 m V cycle-1over 300 cycles at 1C,compared to Li_(1.2)Ni_(0.13)Mn_(0.54)Co_(0.13)O_(2)(Ls)(274.4 mA h g^(-1)for initial capacity,73.8%for ICE and voltage decay of 0.84 mV/cycle over 300 cycles at 1C).Theoretical calculations reveal that the density of states (DOS) area near the Fermi energy level for L1 is larger than that of Ls,indicating higher anionic and cationic redox reactivity than Ls.Moreover,L1 exhibits increased O-vacancy formation energy due to higher Li/Ni disordering of 4.76%(quantified by X-ray diffraction Rietveld refinement) and enhanced TM–O covalency,making lattice O release more difficult and thus improving electrochemical stability.The increased Li/Ni disordering also leads to more Ni^(2+)presence in the Li layer,which acts as a pillar during Li+de-embedding,improving structural stability.This research not only presents a viable approach to designing low-Co LLOs with enhanced capacity and ICE but also contributes significantly to the fundamental understanding of structural regulation in high-performance LIB cathodes.
基金funded by the project from the national natural science foundation of China(21805018 and 21878195)the applied basic research project of Sichuan science and technology department(2020YJ0134)the everest scientific research program of chengdu university of technology。
文摘Li-rich layered transition metal oxides are one of the most promising cathode materials for their high energy density.However,the cathodes usually suffer from severe potential dropping and capacity fading during cycling,which are associated with the surface oxygen release and accompanied by cation densification and structural collapse.Herein,an integrative approach of simultaneous constructing uniform 3d Fe-ion doping in the transition metal layer and Li-rich Li_(5)FeO_(4) shell to grab the oxygen and prevent interfacial side reactions is proposed.The introduction of Fe induces higher redox potential and stronger 3 d Fe-O_(2)p covalent bond,triggering reversible anionic redox via a reductive coupling mechanism.And the delithiated product of Li-rich Li_(5)FeO_(4) not only acts as a protective layer alleviating the side reactions but also enhances the surface kinetic property.With the benefit of promoted reversibility of oxygen redox and enhanced surface stability,the cathode exhibits high reversible capacity and superior cycle performance.Density function theory calculation indicates that the O_(2)p non-bonding state in the cathode incorporated with Fe sits at a lower energy band,resulting in higher energy storage voltage and improved oxygen stability.Consequently,the modified cathode exhibits a discharge specific capacity of 307 m A h g^(-1)(1 C=250 m A g^(-1)),coulombic efficiency of 82.09%in the initial cycle at 0.1 C and 88.34%capacity retention after 100 cycles at 1 C.The work illustrates a strategy that could simultaneously enhance oxygen redox reversibility and interface stability by constructing lattice bond coordination and delithiation induced protective layer to develop Li-rich materials with high reversible capacity and long lifespan.
基金supported by the National Natural Science Foundation of China(22109052,52202221,22150004)Guangdong Basic and Applied Basic Research Foundation(2022B1515020001,2024A1515010277)Guangzhou Science and Technology Program(2024A04J3899).
文摘Two-dimensional conductive metal-organic frameworks(2D c-MOFs)with high flexibility in structure design and functionalization have inspired numerous research interests as promising multifunctional materials due to their porous structure,high conductivity,and rich redox active sites.This review offers a concise overview of 2D c-MOF syntheses and their applications in rechargeable batteries.The electron transport mechanism of 2D c-MOFs will be briefly introduced first.Then we discuss the designs and syntheses of 2D c-MOFs,emphasizing the conjugate structure for high conductivity and the redox activity for efficient energy storage.The electrochemical behaviors of the 2D c-MOFs in different rechargeable battery systems are summarized with attention to their structure-performance correlations and storage mechanism.Particular attention is paid to the significant applied potential of 2D c-MOFs in the Na-ion batteries(NIBs)and Kion batteries(KIBs),which are more sustainable battery chemistries but are plagued by the dissatisfactory battery performances due to the large size of the Na^(+)and K^(+).The challenges and opportunities regarding their efficient synthesis and rechargeable battery applications are also discussed.We expect this review will spark new endeavors to promote the further development of 2D c-MOFs for advanced rechargeable batteries.
基金Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work。
文摘The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using polychelates,PAA-Co X(X:3,5,7,and 10)where X represents the doping fraction(w/w)of Co in PAA.All polymer metal electrolytes were showed excellent bending-stretching properties,thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15×10^(-4) S cm^(-1).Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes.The electric double-layer capacitor(EDLC)and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g^(-1) with a device of PAA-Co7,which is at least 15 times enhancement compared to the device of pristine PAA.The PAA-Co7 device also provided energy density of 21.25 Wh kg^(-1) at a power density of 117.69 W kg^(-1).A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge-discharge cycles and the maintained 90%of its initial performance.In addition,the supercapacitor with a dimension of 1.5 cm×3 cm containing PAA-Co7 successfully operated the red-blue-green(RGB)LED light.
基金supported by the National Key R&D Program of China(Nos.2016YFA0202500 and 2016YFB0901502)the National Natural Science Foundation of China(NSFC,Nos.21673243,51771094 and 21805141)the Ministry of Education(MOE)of China(No.B12015)and Tianjin High-Tech(No.18JCZDJC31500)。
文摘Due to the diversity and feasibility of structural modification for organic molecules,organic-based redox flow batteries(ORFBs)have been widely investigated,especially in aqueous solution under neutral circumstance.In this work,a symmetric aqueous redox flow battery(SARFB)was rationally designed by employing a bipolar redox active molecule(N,N’-dimethyl-4,4-bipyridinium diiodide,MVI2)as both cathode and anode materials and combining with an anion exchange membrane.For one MVI2 flow battery,MV2+/MV·+and I-/I3-serve as the redox couples of anode and cathode,respectively.The MVI2 battery with a working voltage of 1.02 V exhibited a high voltage efficiency of 90.30%and energy efficiency of 89.44%after 450 cycles,and crossover problem was prohibited.The comparable conductivity of MVI2 water solution enabled to construct a battery even without using supporting electrolyte.Besides,the bipolar character of MVI2 battery with/without supporting electrolyte was investigated in the voltage range between-1.2 V and 1.2 V,showing excellent stable cycling stability during the polarity-reversal test.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2502200)the National Natural Science Foundation of China(Grant Nos.52325207,22239003,and 22393904).
文摘Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through synergistic anionic and cationic redox reactions.However,these materials face challenges including oxygen release-induced structural degradation and consequent capacity fading.To address these issues,strategies such as surface modification and bulk phase engineering have been explored.In this study,we developed a facile and cost-effective quenching approach that simultaneously modifies both surface and bulk characteristics.Multi-scale characterization and computational analysis reveal that rapid cooling partially preserves the high-temperature disordered phase in the bulk structure,thereby enhancing the structural stability.Concurrently,Li^(+)/H^(+)exchange at the surface forms a robust rock-salt/spinel passivation layer,effectively suppressing oxygen evolution and mitigating interfacial side reactions.This dual modification strategy demonstrates a synergistic stabilization effect.The enhanced oxygen redox activity coexists with the improved structural integrity,leading to superior electrochemical performance.The optimized cathode delivers an initial discharge capacity approaching 307.14 mAh/g at 0.1 C and remarkable cycling stability with 94.12%capacity retention after 200 cycles at 1 C.This study presents a straightforward and economical strategy for concurrent surface–bulk modification,offering valuable insights for designing high-capacity LRM cathodes with extended cycle life.
基金National Natural Science Foundation of China,Grant/Award Numbers:22279166,52002157National Institute of Education,Singapore,under its Academic Research Fund,Grant/Award Numbers:RI 1/21 EAH,RI 3/23 EAH+1 种基金China Postdoctoral Science Foundation,Grant/Award Numbers:2022M711686,2023M741471Postgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:SJCX24_2512。
文摘The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,these organic molecules often exhibit sluggish reaction kinetics and unsatisfactory utilization of active sites,presenting significant challenges for their practical deployment as electrode materials in aqueous batteries.In this study,we have synthesized a novel organic compound(PTPZ),comprised of a centrally symmetric and fully ladder-type structure,tailored for aqueous proton storage.This unique configuration imparts the PTPZ molecule with high electron delocalization and enhanced structural stability.As an electrode material,PTPZ demonstrates a substantial proton-storage capacity of 311.9mAh g^(-1),with an active group utilization efficiency of up to 89% facilitated by an 8-electron transfer process,while maintaining a capacity retention of 92.89% after 8000 chargingdischarging cycles.Furthermore,in-situ monitoring technologies and various theoretical analyses have pinpointed the associated electrochemical processes of the PTPZ electrode,revealing exceptional redox activity,rapid proton diffusion,and efficient charge transfer.These attributes confer a significant competitive advantage to PTPZ as an anode material for high-performance proton storage devices.Consequently,this work contributes to the rational design of organic electrode materials for the advancement of rechargeable aqueous batteries.
基金supported by the National Natural Science Foundation of China(under grant numbers 12174272 and 11974136)。
文摘α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.
基金financial support from the National Natural Science Foundation of China(Grant Nos.52172198,51902117,91733301)。
文摘The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.
基金supported by the National Natural Science Foundation of China(nos.41063006,41363007,and 41273099)the Science and Technology Fund of Guizhou Province(no.[2013]2296)
文摘Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria（SRB） on mercury（Hg） methylation at sediment–water interfaces. Concentrations of dissolved methyl mercury（DMe Hg） in the overlying water of the control cores with bioactivity maintained（BAC） and cores with only sulfate-reducing bacteria inhibited（SRBI） and bacteria fully inhibited（BACI） were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMe Hg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations（r =- 0.5311 and r =- 0.4977 for BAC and SRBI, respectively）. The water DMe Hg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment–water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster（hgc AB）, besides SRB,causing Hg methylation in the sediment–water system.
基金supported by the National Natural Science Foundation of China (Nos. 21871074 and 21971051)the National Key R&D Program of China (No. 2018YFB1501604)+1 种基金the Fundamental Research Funds for the Central Universities (No. PA2020GDKC0021)the Key Research and Development Program Projects in Anhui Province (No. 201904a07020069)。
文摘An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.
基金financially supported by the National Natural Science Foundation of China (Nos. 51972258 and 22109186)Open Fund by Sanya Science and Education Innovation Park of Wuhan University of Technology (No. 2021KF0021)supported by 21C Innovation Laboratory,Contemporary Amperex Technology Ltd. by Project No. 21C-OP-202002。
文摘Lithium rich layered oxide(LRLO) has been considered as one of the promising cathodes for lithium-ion batteries(LIBs). The high voltage and large capacity of LRLO depend on Li2MnO_(3)phase. To ameliorate the electrochemical performance of Li2MnO_(3), also written as Li(Li1/3Mn2/3)O_(2), we propose a strategy to substitute Mn4+and Li+in Mn/Li transition metal layer with Ti4+, which can stabilize the structure of Li2MnO_(3)by inhibiting the excessive oxidation of O_(2)-above 4.5 V. More significantly, the unequal-valent substitution brings about the emergence of interlayer Li vacancies, which can promote the Li-ion diffusion based on the enlarged interlayer and increase the capacity by activating the Mn3+/4+redox. We designed Li0.7[Li1/3Mn2/3]0.7Ti0.3O_(2)with high interlayer Li vacancies, which presents a high capacity(290 m Ah/g at 10 m A/g) and stable cycling performance(84% over 60 cycles at 50 m A/g). We predict that this strategy will be helpful to further improve the electrochemical performance of LRLOs.
基金We thank the financial supports from the National Natural Science Foundation of China，the Science and Technology Commission of Shanghai Municipality
文摘Seven square planar bis（o-diiminobenzosemiquinonato）nickel（II） complexes, [Ni（o-C6H4（NH）（NAr））2] （Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3）, [Ni（o-4,5-F2-C6H2（NH）（NPh））2] （4）, and [Ni（o-4,5-CIz-C6H2（NH）（NAr））2] （Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7）, have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies （1 and 7）. The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n＋. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni（o-C6Ha（NH）（NPh））2] （8） and [Ni（o-3,5-Butz-C6Hz（NH）2）2] （9）, are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na（THF）3][I] and [Na（THF）3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill（lL-1 ）（IL2-）]1- and [Ni1]（1L2 ）212-, which are in line with those of [9]n （n = 1-, 2-） suggested by spectroelectrochemical study.
基金supported by grants from the National Key Research and Development Program of China(grant number 2017YFC1104900)the National Natural Science Foundation of China(No.82372124,51871239,and 51771227)+1 种基金the support from the Incubation Program of China Army Medical Science and Technology Youth Training Program(No.17QNP021)the Everest Program of Air Force Military Medical University(No.2020ZFC002)。
文摘Given post-operative aseptic loosening in orthopedic disease treatment,osteointegration occurs at the bone-implant interface as a holistic process,including immunoregulation(e.g.,macrophage polarization),angiogenesis and osteogenesis in sequence.In order to achieve early rapid and satisfactory osseointegration,different nano-shaped(nanocone,nanopolyhedron and nanoflower abbr.NC,NP&NF)cerium oxide(CeO_(2-x))coatings,endowed with“nanozyme-like”activities for multiple free radical elimination and osteoimmunology regulation,were hydrothermally synthesized on titanium alloy(TC4).In vitro cell experiments showed that nano-CeO_(2-x) coated TC4 not only induced polarization of RAW264.7 cells toward M2 phenotype,but also promoted angiogenesis and vascularization of endothelial cells along with differentiation and mineralization of osteogenic precursor cells.Improvements in M2-polarized macrophage,angiogenesis,and bone regeneration were further confirmed in a rat femoral condyle model.Among the above three nano-morphologies,NF exhibited the best osseoinetegration.RNA sequencing and mechanism exploration suggested that the inhibition of PI3K-AKT signaling pathway was essential for immunomodulatory capacity of NF.In conclusion,it provided promising insights into the immunomodulatory exploitation of orthopedic implants.
