The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties ...The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.展开更多
Recently,rechargeable zinc-ion batteries have been considered as the future development direction of large-scale energy storage due to their low price,safety,environmental friendliness,and excellent electrochemical pe...Recently,rechargeable zinc-ion batteries have been considered as the future development direction of large-scale energy storage due to their low price,safety,environmental friendliness,and excellent electrochemical performance.However,highcapacity,long-cycle stable cathode materials that can meet the demand are still to be developed.Herein,the hollow mesoporous ZnMn2O4/C microsphere cathode material with carbon nanotubes embedded in the shell was prepared by spray pyrolysis for the first time.Its capacity remained at 209.71 mAh·g−1 after 150 cycles at a rate of 0.5 A·g−1,and still maintained a specific capacity of 100.06 mAh·g−1 at a rate of 1 A·g−1 after 1,000 cycles.The outstanding performance is attributed to the hollow structure that can effectively buffer large volume changes caused by ion intercalation and deintercalation,excellent porosity,cationic defects,and high electrical conductivity of carbon nanotubes and its strong adsorption to ZnMn2O4 nanoparticles.展开更多
Currently, lithium-ion batteries play a key role in energy storage; however, their applications are limited by their low energy density. Here, we design a facile method to prepare mesoporous ZnMn2O4 microspheres with ...Currently, lithium-ion batteries play a key role in energy storage; however, their applications are limited by their low energy density. Here, we design a facile method to prepare mesoporous ZnMn2O4 microspheres with ultrahigh rate performance and ultralong cycling properties by finely tuning the solution viscosity during synthesis. When the current density is raised to 2 A·g^-1, the discharge capacity is maintained at 879 mA·h·g^-1 after 500 cycles. The electro- chemical properties of mesoporous ZnMn2O4 microspheres are better than that for most reported ZnMn2O4. To understand the electrochemical processes on the mesoporous ZnMn2O4 microspheres, in situ Raman spectroscopy is used to investigate the electrode surface. The results show that mesoporous ZnMn2O4 microspheres have a great potential as an alternative to commercial carbon anode materials.展开更多
A ZnMn2O4 catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques.It is composed of numerous nanoparticles(15-110 nm)assembled into a porous structure wit...A ZnMn2O4 catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques.It is composed of numerous nanoparticles(15-110 nm)assembled into a porous structure with a specific surface area(SSA)o f 19.1 m^2.g^-1.Its catalytic activity has been investigated for the degradation of orange II dye using three different systems,i.e.,the photocatalysis system with visible light,the chemocatalysis system with bisulfite,and the photochemical catalysis system with both visible light and bisulfite.The last system exhibits the maximum degradation efficiency of 90%,much higher than the photocatalysis system(15%)and the chemocatalysis system(67%).The recycling experiments indicate that the ZnMn204 catalyst has high stability and reusability and is thus a green and eximious catalyst.Furthermore,the potential degradation mechanisms applicable to the three systems are discussed with relevant theoretical analysis and scavenging experiments for radicals.The active species such as Mn(III),o2^-,H^+,eaq,So4^- and Ho^-are proposed to be responsible for the excellent degradation results in the photo-chemical catalysis system with the ZnMn2o4 catalyst.展开更多
基金Ting-ting FENG acknowledges the financial support from Professor Paul V.BRAUN at Department of Materials Science and Engineering,University of Illinois at Urbana-Champaign,the support from Chinese Scholarship Council during her visit to University of Illinois at Urbana-Champaign,partial financial supports from Department of Science and Technology of Sichuan Province,China(2019YFH0002,2019YFG0222 and 2019YFG0526).The research was partly carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities,University of Illinois at Urbana-Champaign.
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.
基金This work was supported by the National Natural Science Foundation of China(Nos.21871005 and 22171005)the University Synergy Innovation Program of Anhui Province(Nos.GXXT-2020-005,GXXT-2021-012,and GXXT-2021-013)Open project of Shanghai Institute of Technical Physics(No.IIMOKFJJ-19-09).
文摘Recently,rechargeable zinc-ion batteries have been considered as the future development direction of large-scale energy storage due to their low price,safety,environmental friendliness,and excellent electrochemical performance.However,highcapacity,long-cycle stable cathode materials that can meet the demand are still to be developed.Herein,the hollow mesoporous ZnMn2O4/C microsphere cathode material with carbon nanotubes embedded in the shell was prepared by spray pyrolysis for the first time.Its capacity remained at 209.71 mAh·g−1 after 150 cycles at a rate of 0.5 A·g−1,and still maintained a specific capacity of 100.06 mAh·g−1 at a rate of 1 A·g−1 after 1,000 cycles.The outstanding performance is attributed to the hollow structure that can effectively buffer large volume changes caused by ion intercalation and deintercalation,excellent porosity,cationic defects,and high electrical conductivity of carbon nanotubes and its strong adsorption to ZnMn2O4 nanoparticles.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21522508, 51625402, and 21521004）, the Fundamental Research Funds for the Central Universities （No. 20720150039）, ＂111＂ Project （Nos. B16029 and B17027）, and the Thousand Youth Talents Plan of China.
文摘Currently, lithium-ion batteries play a key role in energy storage; however, their applications are limited by their low energy density. Here, we design a facile method to prepare mesoporous ZnMn2O4 microspheres with ultrahigh rate performance and ultralong cycling properties by finely tuning the solution viscosity during synthesis. When the current density is raised to 2 A·g^-1, the discharge capacity is maintained at 879 mA·h·g^-1 after 500 cycles. The electro- chemical properties of mesoporous ZnMn2O4 microspheres are better than that for most reported ZnMn2O4. To understand the electrochemical processes on the mesoporous ZnMn2O4 microspheres, in situ Raman spectroscopy is used to investigate the electrode surface. The results show that mesoporous ZnMn2O4 microspheres have a great potential as an alternative to commercial carbon anode materials.
基金the National Natural Science Foundation of China(Grant No.21477009)Natural Science Foundation of Jiangsu Province(No.SBK2016021419)+1 种基金“333 project”of Jiangsu Province and the Opening Project of Guangxi Key Laboratory of Green Processing of Sugar Resources(No.GXTZY201803)One of us(SK)was supported by the College of Agricultural Sciences under Station Research Project No.PEN04566.
文摘A ZnMn2O4 catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques.It is composed of numerous nanoparticles(15-110 nm)assembled into a porous structure with a specific surface area(SSA)o f 19.1 m^2.g^-1.Its catalytic activity has been investigated for the degradation of orange II dye using three different systems,i.e.,the photocatalysis system with visible light,the chemocatalysis system with bisulfite,and the photochemical catalysis system with both visible light and bisulfite.The last system exhibits the maximum degradation efficiency of 90%,much higher than the photocatalysis system(15%)and the chemocatalysis system(67%).The recycling experiments indicate that the ZnMn204 catalyst has high stability and reusability and is thus a green and eximious catalyst.Furthermore,the potential degradation mechanisms applicable to the three systems are discussed with relevant theoretical analysis and scavenging experiments for radicals.The active species such as Mn(III),o2^-,H^+,eaq,So4^- and Ho^-are proposed to be responsible for the excellent degradation results in the photo-chemical catalysis system with the ZnMn2o4 catalyst.
文摘采用溶胶凝胶法合成出锂离子电池用Zn Mn2O4负极材料,并用XRD,SEM和电化学性能测试对材料进行了表征。实验结果表明,随着焙烧温度与时间升高,晶体结晶更好。在焙烧温度达到800℃,焙烧时间为12 h时,能够形成单一四方相尖晶石结构的Zn Mn2O4粉体,结晶良好,当焙烧温度和时间继续升高,颗粒会出现较大的团聚体;将所制备的Zn Mn2O4粉体组装成扣式电池进行电化学测试的结果表明,800℃焙烧12 h的样品具有较好的电化学性能。首次充放电比容量分别为1096 m Ah·g-1和1310 m Ah·g-1,库伦效率为83.66%。有望成为锂离子电池石墨负极替代材料。
