近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的Mn...近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的MnO纳米颗粒,为立方晶系结构,作为Li-O2电池阴极在500次循环中表现出优异的循环稳定性,首次充电过电位为0.46 V,在500 mA·g−1的高电流密度下实现了1000 h的稳定循环,优于大多数已报道的用于Li-O2电池的MnOx催化剂。In recent years, transition metal oxides have been considered the most promising materials to replace precious metals as cathode catalysts for lithium-oxygen batteries. This study investigates MnO nanoparticles that spontaneously form after calcining electrospun fibers as an efficient catalyst for lithium-oxygen (Li-O2) batteries. Physical characterization shows that MnO nanoparticles with an average particle size of 61.82 nm and a cubic crystal structure were successfully synthesized. They exhibit excellent cycling stability as a cathode in Li-O2 batteries, enduring over 500 cycles with an initial overpotential of 0.46 V. Concurrent, they also achieve stable cycling for 1000 hours at a high current density of 500 mA·g−1, outperforming most reported catalysts such as MnOx for Li-O2 batteries.展开更多
The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal de...The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal deposition behaviors through in situ forming stable artificial solid electrolyte interface(SEI)passivating layers.The concentration of MnO in the cells can be maintained at a constant based on quite low solubility of MnO in the liquid electrolyte,and the dissolved MnO can be reduced to produce Li_(2)O and Mn metal nanoparticles,which can not only function as nucleating seeds of lithium metal deposits but also repair the broken SEI layer.Dendritic-free Li deposits can be obtained by simple separator coating.It can also improve the electrochemical performance of lithium metal batteries.And it is benefit for applications of Li metal anodes.展开更多
The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effec...The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effective direct heating method for synthesizing MnO2 nanoflowers on coil substrates for the removal of organic pollutants.Traditional methods often require high power,expensive equipment,and long synthesis times.In contrast,the direct heating approach successfully synthesized MnO2 nanoflowers in just 10 min with a heating power of approximately 40 W·h after the heating power and duration were optimized.These nanoflowers effectively degraded 99%Rhodamine B in 60 min with consistent repeatability.The catalytic mechanisms are attributed to crystal defects in MnO2,which generate electrons to produce H2O2.Mn2+ions in the acidic solution further dissociate H2O2 molecules into hydroxyl radicals(·OH).The high efficiency of this synthesis method and the excellent reusability of MnO2 nanoflowers highlight their potential as a promising solution for the development of supporting MnO2 catalysts for organic dye removal applications.展开更多
Rational developing high-performance and economically efficient dual-functional oxygen electrocatalysts to drive the lumberly reactivity rates of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in Zn-a...Rational developing high-performance and economically efficient dual-functional oxygen electrocatalysts to drive the lumberly reactivity rates of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in Zn-air batteries is highly attractive,yet remains conceptually challenging.Herein,Ni/MnO heterostructure nanosheets and nanoparticles firmly anchored onto the N-doped carbon nanofibers(noted as Ni/MnO@N-C NS/NFs)for efficient bifunctional ORR/OER electrocatalysis are designed and realized through a facile electrospinning-pyrolysis-etching strategy.The epitaxial in situ grown Ni/MnO with enriched oxygen vacancies stimulated the charge redistribution in their coupling regions,which effectively optimizes the adsorption/desorption of O-related intermediates in ORR/OER.Benefiting from the Ni/MnO heterostructure moieties and the unique two-dimensional/one-dimensional(2D/1D)superstructure of carbon support with abundantly dispersive active species,the resultant Ni/MnO@N-C NS/NFs deliver robust ORR activity and OER property(an overpotential of 306 mV to obtain 10 mA·cm^(-2))with a smaller potential gap(ΔE=0.77 V)in alkaline electrolyte.More significantly,practical zinc-air battery building with Ni/MnO@N-C NS/NFs delivers a higher open circuit voltage,excellent output power density,and prominent durability with stable charging and discharging cycle life.The present work demonstrates a crucial understanding of building advanced heterostructure electrocatalysts with enriched oxygen vacancies for metal-air batteries application.展开更多
The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary mate...The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary material.Consequently,this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method,marking its initial application in aqueous magnesium ion capacitors(AMICs).The fabricated MnS/MnO heterostructure,characterized by S defects,also generates Mn defects via in-situ initiation of early electrochemical processes.This unique dual ion defects MnS/MnO heterostructure(DID-MnS/MnO)enables the transformation of MnS and MnO,initially not highly active electrochemically for Mg^(2+),into cathode materials exhibiting high electrochemical activity and superior performance.Moreover,DID-MnS/MnO enhances conductivity,improves the kinetics of surface redox reactions,and increases the diffusion rate of Mg^(2+).Furthermore,this study introduces a dual energy storage mechanism for DID-MnS/MnO,which,in conjunction with dual ion defects,offers additional active sites for Mg^(2+)insertion/deinsertion in the host material,mitigating volume expansion and structural degradation during repeated charge-discharge cycles,thereby significantly enhancing cycling reversibility.As anticipated,using a three-electrode system,the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of 0.1 A/g.Remarkably,the constructed AMIC maintained a capacity retention rate of 94.3%after 10000 cycles at a current density of 1.0 A/g,with a specific capacitance of 165.7 F/g.Hence,DID-MnS/MnO offers insightful perspectives for designing alternative clean energy sources and is expected to contribute significantly to the advancement of the clean energy sector.展开更多
Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is s...Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.展开更多
文摘近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的MnO纳米颗粒,为立方晶系结构,作为Li-O2电池阴极在500次循环中表现出优异的循环稳定性,首次充电过电位为0.46 V,在500 mA·g−1的高电流密度下实现了1000 h的稳定循环,优于大多数已报道的用于Li-O2电池的MnOx催化剂。In recent years, transition metal oxides have been considered the most promising materials to replace precious metals as cathode catalysts for lithium-oxygen batteries. This study investigates MnO nanoparticles that spontaneously form after calcining electrospun fibers as an efficient catalyst for lithium-oxygen (Li-O2) batteries. Physical characterization shows that MnO nanoparticles with an average particle size of 61.82 nm and a cubic crystal structure were successfully synthesized. They exhibit excellent cycling stability as a cathode in Li-O2 batteries, enduring over 500 cycles with an initial overpotential of 0.46 V. Concurrent, they also achieve stable cycling for 1000 hours at a high current density of 500 mA·g−1, outperforming most reported catalysts such as MnOx for Li-O2 batteries.
文摘The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal deposition behaviors through in situ forming stable artificial solid electrolyte interface(SEI)passivating layers.The concentration of MnO in the cells can be maintained at a constant based on quite low solubility of MnO in the liquid electrolyte,and the dissolved MnO can be reduced to produce Li_(2)O and Mn metal nanoparticles,which can not only function as nucleating seeds of lithium metal deposits but also repair the broken SEI layer.Dendritic-free Li deposits can be obtained by simple separator coating.It can also improve the electrochemical performance of lithium metal batteries.And it is benefit for applications of Li metal anodes.
基金supported by Ministry of Higher Education,Malaysia,through the Fundamental Research Grant Scheme(FRGS)(Grant No.FRGS/1/2020/TK0/USM/02/27)。
文摘The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effective direct heating method for synthesizing MnO2 nanoflowers on coil substrates for the removal of organic pollutants.Traditional methods often require high power,expensive equipment,and long synthesis times.In contrast,the direct heating approach successfully synthesized MnO2 nanoflowers in just 10 min with a heating power of approximately 40 W·h after the heating power and duration were optimized.These nanoflowers effectively degraded 99%Rhodamine B in 60 min with consistent repeatability.The catalytic mechanisms are attributed to crystal defects in MnO2,which generate electrons to produce H2O2.Mn2+ions in the acidic solution further dissociate H2O2 molecules into hydroxyl radicals(·OH).The high efficiency of this synthesis method and the excellent reusability of MnO2 nanoflowers highlight their potential as a promising solution for the development of supporting MnO2 catalysts for organic dye removal applications.
基金supported by the National Natural Science Foundation of China(No.22302096)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Nos.23KJB150039 and 24KJB150026)+1 种基金Natural Science Foundation of Zhejiang Province(No.LQ24E040002)the Natural Science Foundation of Huzhou City(No.2023YZ18).
文摘Rational developing high-performance and economically efficient dual-functional oxygen electrocatalysts to drive the lumberly reactivity rates of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in Zn-air batteries is highly attractive,yet remains conceptually challenging.Herein,Ni/MnO heterostructure nanosheets and nanoparticles firmly anchored onto the N-doped carbon nanofibers(noted as Ni/MnO@N-C NS/NFs)for efficient bifunctional ORR/OER electrocatalysis are designed and realized through a facile electrospinning-pyrolysis-etching strategy.The epitaxial in situ grown Ni/MnO with enriched oxygen vacancies stimulated the charge redistribution in their coupling regions,which effectively optimizes the adsorption/desorption of O-related intermediates in ORR/OER.Benefiting from the Ni/MnO heterostructure moieties and the unique two-dimensional/one-dimensional(2D/1D)superstructure of carbon support with abundantly dispersive active species,the resultant Ni/MnO@N-C NS/NFs deliver robust ORR activity and OER property(an overpotential of 306 mV to obtain 10 mA·cm^(-2))with a smaller potential gap(ΔE=0.77 V)in alkaline electrolyte.More significantly,practical zinc-air battery building with Ni/MnO@N-C NS/NFs delivers a higher open circuit voltage,excellent output power density,and prominent durability with stable charging and discharging cycle life.The present work demonstrates a crucial understanding of building advanced heterostructure electrocatalysts with enriched oxygen vacancies for metal-air batteries application.
基金supported by the National Natural Science Foundation of China(Nos.52071171,52202248)Liaoning BaiQianWan Talents Program(LNBQW2018B0048)+8 种基金Shenyang Science and Technology Project(21-108-9-04)Key Research Project of Department of Education of Liaoning Province(LJKZZ20220015)the Research Fund for the Doctoral Program of Liaoning Province(2022-BS-114)Chunhui Program of the Ministry of Education of the People’s Republic of China(202201135)Australian Research Council(ARC)through Future Fellowship(FT210100298,FT210100806)Discovery Project(DP220100603)Linkage Project(LP210100467,LP210200504,LP210200345,LP220100088)Industrial Transformation Training Centre(IC180100005)schemes,and the Australian Government through the Cooperative Research Centres Projects(CRCPXIII000077)the Australian Renewable Energy Agency(ARENA)as part of ARENA’s Transformative Research Accelerating Commercialisation Program(TM021).
文摘The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary material.Consequently,this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method,marking its initial application in aqueous magnesium ion capacitors(AMICs).The fabricated MnS/MnO heterostructure,characterized by S defects,also generates Mn defects via in-situ initiation of early electrochemical processes.This unique dual ion defects MnS/MnO heterostructure(DID-MnS/MnO)enables the transformation of MnS and MnO,initially not highly active electrochemically for Mg^(2+),into cathode materials exhibiting high electrochemical activity and superior performance.Moreover,DID-MnS/MnO enhances conductivity,improves the kinetics of surface redox reactions,and increases the diffusion rate of Mg^(2+).Furthermore,this study introduces a dual energy storage mechanism for DID-MnS/MnO,which,in conjunction with dual ion defects,offers additional active sites for Mg^(2+)insertion/deinsertion in the host material,mitigating volume expansion and structural degradation during repeated charge-discharge cycles,thereby significantly enhancing cycling reversibility.As anticipated,using a three-electrode system,the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of 0.1 A/g.Remarkably,the constructed AMIC maintained a capacity retention rate of 94.3%after 10000 cycles at a current density of 1.0 A/g,with a specific capacitance of 165.7 F/g.Hence,DID-MnS/MnO offers insightful perspectives for designing alternative clean energy sources and is expected to contribute significantly to the advancement of the clean energy sector.
基金supported by the National Natural Science Foundation of China(Nos.U2030206,12104022,52271014 and 22075003)the Presidential Foundation of CAEP(No.YZJJZL2023173)Sichuan Science and Technology Program(No.2021YFH0092).
文摘Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.
