The development of self-charging supercapacitor power cells(SCSPCs)has profound implications for smart electronic devices used in different fields.Here,we epitaxially electrodeposited Mo-and Fe-codoped MnO_(2)films on...The development of self-charging supercapacitor power cells(SCSPCs)has profound implications for smart electronic devices used in different fields.Here,we epitaxially electrodeposited Mo-and Fe-codoped MnO_(2)films on piezoelectric ZnO nanoarrays(NAs)grown on the flexible carbon cloth(denoted ZnO@Mo-Fe-MnO_(2)NAs).A self-charging supercapacitor power cell device was assembled with the Mo-and Fe-codoped MnO_(2)nanoarray electrode and poly(vinylidenefluoride-co-trifluoroethylene)(PVDF-Trfe)piezoelectric film doped with BaTiO_(3)(BTO)and carbon nanotubes(CNTs)(denoted PVDF-Trfe/CNTs/BTO).The self-charging supercapacitor power cell device exhibited an energy density of 30μWh cm^(-2)with a high power density of 40 mW cm^(-2)and delivered an excellent self-charging performance of 363 mV(10 N)driven by both the piezoelectric ZnO nanoarrays and the poly(vinylidenefluoride-co-trifluoroethylene)piezoelectric film doped with BaTiO_(3)and carbon nanotubes.More intriguingly,the device could also be self-charged by 184 mV due to residual stress alone and showed excellent energy conversion efficiency and low self-discharge rate.This work illustrates for the first time the self-charging mechanism involving electrolyte ion migration driven by both electrodes and films.A comprehensive analysis strongly confirmed the important contribution of the piezoelectric ZnO nanoarrays in the self-charging process of the self-charging supercapacitor power cell device.This work provides novel directions and insights for the development of selfcharging supercapacitor power cells.展开更多
MnO_(2)作为超级电容器电极材料具有理论比电容高、成本低、环境友好等优点,但其低导电性和低利用率阻碍了其潜在应用.本研究首先在柔性碳布上电化学生长ZnO纳米棒阵列作为电极衬底,然后通过阳极电沉积法在ZnO纳米棒阵列表面外延生长了M...MnO_(2)作为超级电容器电极材料具有理论比电容高、成本低、环境友好等优点,但其低导电性和低利用率阻碍了其潜在应用.本研究首先在柔性碳布上电化学生长ZnO纳米棒阵列作为电极衬底,然后通过阳极电沉积法在ZnO纳米棒阵列表面外延生长了Mo和碳纳米管(CNTs)共掺杂的MnO_(2)薄膜,可控构筑了有效、高导电性的MnO_(2)纳米阵列电极(定义为ZnO@Mo-CNT-MnO_(2)NA).柔性ZnO@Mo-CNTMnO_(2)NA电极在100 A g^(-1)的大电流充放电密度下比电容可达237.5 F g^(-1),10,000次循环后电容保留率高达86%.采用ZnO@Mo-CNTMnO_(2)NA电极组装成水系非对称超级电容器,弯曲状态下在132.35 mW cm^(-3)(5mA cm^(-2))高功率密度下获得了1.13 mW h cm^(-3)的高能量密度,5mA cm^(-2)充放电倍率下循环7600次后电容保留率高达88%.本研究构筑的MnO_(2)基纳米阵列电极结构可提高其电导率和利用率,为柔性金属氧化物超级电容器电极的设计与制备提供新途径.展开更多
The kinetic process of a slow oxygen evolution reaction (OER) always constrains the efficiency of overall water electrolysis for H2 production.In particular,nonprecious metal electrodes for the OER have difficulty in ...The kinetic process of a slow oxygen evolution reaction (OER) always constrains the efficiency of overall water electrolysis for H2 production.In particular,nonprecious metal electrodes for the OER have difficulty in possessing excellent electrocatalytic activity and stability in pH-universal media simultaneously.In this work,urea is first used as a pore-forming agent and active C/N source to fabricate a nanoporous NiFeCoCN medium-entropy alloy (MEA) by high-temperature sintering based on the nanoscale Kirkendall effect.The NiFeCoCN MEA achieves an overpotential of 432 mV at a current density of 10 mA·cm^(-2) and a lower Tafel slope of 52.4 mV·dec^(-1) compared to the IrO_(2)/Ti electrode (58.6 mV·dec^(-1)) in a 0.5 mol/L H_(2)SO_(4) solution.In a 1 mol/L KOH solution,the NiFeCoCN MEA obtains an overpotential of 175 mV for 10 mA·cm^(-2) and a Tafel slope of 40.8 mV·dec^(-1),which is better than IrO_(2)/Ni foam.This work proves a novel strategy to design and prepare nanoporous MEA materials with desirable C/N species,which provides promising prospects for the industrial production of H2 energy.展开更多
This article examines the late Qing urban transformation as a conscious effort by reformist officials, like Zhang Zhidong, to confront imperialist expansion and the challenges of the treaty port system during the dyna...This article examines the late Qing urban transformation as a conscious effort by reformist officials, like Zhang Zhidong, to confront imperialist expansion and the challenges of the treaty port system during the dynasty＇s last decades. It shows how ＂commercial warfare （shangzharo＂ thought among the urban, reformist elite provided impetus for the radical transformation of traditional cities from military and administrative centers to battlefields of commercial warfare （shangzhan） against the West. No place better illustrates the urban structural changes in the late Qing dynasty than the tri-cities of Wuchang, Hanyang, and Hankou, the base of Zhang Zhidong＇s late Qing reform in Hubei. Zhang＇s daring urban modernizing efforts replaced the hierarchical structure of the three cities with relatively equal and symbiotic relationships. More importantly, Zhang Zhidong resurrected the concept of shangzhan （commercial warfare）--the idea that China could fight foreign expansion through commercial competition, which Zeng Guofan first used to address Western commercial advancement in the 1860s. This thought enabled Zhang to use the increasing global pressure and Chinese nationalistic sentiments to advance his reform agenda and break from the restrictions of the traditional urban ideal. Analyzing the intellectual foundations of late Qing urban reform is also crucial to understanding cities＇ central position in Qing＇s defensive global engagement.展开更多
基金the support by the Key Research and Development Program of Jiangxi Province(20203BBE53069)the National Key R&D Program of China(2017YFA0208200)+5 种基金the National Natural Science Foundation of China(51862026,22022505,and 21872069)the Fundamental Research Funds for the Central Universities of China(02051438026,020514380272 and 020514380274)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(BK20220008)the Natural Science Foundation of Jiangxi Province(20192ACBL21048)the Nanjing International Col aboration Research Program(202201007 and 2022SX00000955)the Suzhou Gusu Leading Talent Program of Science and Technology Innovation and Entrepreneurship in Wujiang District(ZXL2021273)
文摘The development of self-charging supercapacitor power cells(SCSPCs)has profound implications for smart electronic devices used in different fields.Here,we epitaxially electrodeposited Mo-and Fe-codoped MnO_(2)films on piezoelectric ZnO nanoarrays(NAs)grown on the flexible carbon cloth(denoted ZnO@Mo-Fe-MnO_(2)NAs).A self-charging supercapacitor power cell device was assembled with the Mo-and Fe-codoped MnO_(2)nanoarray electrode and poly(vinylidenefluoride-co-trifluoroethylene)(PVDF-Trfe)piezoelectric film doped with BaTiO_(3)(BTO)and carbon nanotubes(CNTs)(denoted PVDF-Trfe/CNTs/BTO).The self-charging supercapacitor power cell device exhibited an energy density of 30μWh cm^(-2)with a high power density of 40 mW cm^(-2)and delivered an excellent self-charging performance of 363 mV(10 N)driven by both the piezoelectric ZnO nanoarrays and the poly(vinylidenefluoride-co-trifluoroethylene)piezoelectric film doped with BaTiO_(3)and carbon nanotubes.More intriguingly,the device could also be self-charged by 184 mV due to residual stress alone and showed excellent energy conversion efficiency and low self-discharge rate.This work illustrates for the first time the self-charging mechanism involving electrolyte ion migration driven by both electrodes and films.A comprehensive analysis strongly confirmed the important contribution of the piezoelectric ZnO nanoarrays in the self-charging process of the self-charging supercapacitor power cell device.This work provides novel directions and insights for the development of selfcharging supercapacitor power cells.
基金supported by the National Key R&D Program of China(2017YFA0208200)the National Natural Science Foundation of China(51862026,22022505 and 21872069)+4 种基金the Aeronautical Science Foundation of China(2017ZF56027)the Natural Science Foundation of Jiangxi Province(20192ACBL21048)the Key Research and Development Program of Jiangxi Province(20203BBE53069)the Fundamental Research Funds for the Central Universities(020514380266,020514380272 and 020514380274)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(BK20220008)。
文摘MnO_(2)作为超级电容器电极材料具有理论比电容高、成本低、环境友好等优点,但其低导电性和低利用率阻碍了其潜在应用.本研究首先在柔性碳布上电化学生长ZnO纳米棒阵列作为电极衬底,然后通过阳极电沉积法在ZnO纳米棒阵列表面外延生长了Mo和碳纳米管(CNTs)共掺杂的MnO_(2)薄膜,可控构筑了有效、高导电性的MnO_(2)纳米阵列电极(定义为ZnO@Mo-CNT-MnO_(2)NA).柔性ZnO@Mo-CNTMnO_(2)NA电极在100 A g^(-1)的大电流充放电密度下比电容可达237.5 F g^(-1),10,000次循环后电容保留率高达86%.采用ZnO@Mo-CNTMnO_(2)NA电极组装成水系非对称超级电容器,弯曲状态下在132.35 mW cm^(-3)(5mA cm^(-2))高功率密度下获得了1.13 mW h cm^(-3)的高能量密度,5mA cm^(-2)充放电倍率下循环7600次后电容保留率高达88%.本研究构筑的MnO_(2)基纳米阵列电极结构可提高其电导率和利用率,为柔性金属氧化物超级电容器电极的设计与制备提供新途径.
基金supported by the National Key R&D Program of China(2017YFA0208200)the National Natural Science Foundation of China(51862026,22022505 and 21872069)+6 种基金the Aeronautical Science Foundation of China(2017ZF56027)the Natural Science Foundation of Jiangxi Province(20192ACBL21048)the Key Research and Development Program of Jiangxi Province(20203BBE53069)the Fundamental Research Funds for the Central Universities of China(020514380266,020514380272 and 020514380274)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(BK20220008)the Nanjing International Collaboration Research Program(202201007 and 2022sx00000955)the 2021 Suzhou Gusu Leading Talent Program of Science and Technology Innovationand Entrepreneurship in Wujiang District(ZXL2021273).
文摘The kinetic process of a slow oxygen evolution reaction (OER) always constrains the efficiency of overall water electrolysis for H2 production.In particular,nonprecious metal electrodes for the OER have difficulty in possessing excellent electrocatalytic activity and stability in pH-universal media simultaneously.In this work,urea is first used as a pore-forming agent and active C/N source to fabricate a nanoporous NiFeCoCN medium-entropy alloy (MEA) by high-temperature sintering based on the nanoscale Kirkendall effect.The NiFeCoCN MEA achieves an overpotential of 432 mV at a current density of 10 mA·cm^(-2) and a lower Tafel slope of 52.4 mV·dec^(-1) compared to the IrO_(2)/Ti electrode (58.6 mV·dec^(-1)) in a 0.5 mol/L H_(2)SO_(4) solution.In a 1 mol/L KOH solution,the NiFeCoCN MEA obtains an overpotential of 175 mV for 10 mA·cm^(-2) and a Tafel slope of 40.8 mV·dec^(-1),which is better than IrO_(2)/Ni foam.This work proves a novel strategy to design and prepare nanoporous MEA materials with desirable C/N species,which provides promising prospects for the industrial production of H2 energy.
文摘This article examines the late Qing urban transformation as a conscious effort by reformist officials, like Zhang Zhidong, to confront imperialist expansion and the challenges of the treaty port system during the dynasty＇s last decades. It shows how ＂commercial warfare （shangzharo＂ thought among the urban, reformist elite provided impetus for the radical transformation of traditional cities from military and administrative centers to battlefields of commercial warfare （shangzhan） against the West. No place better illustrates the urban structural changes in the late Qing dynasty than the tri-cities of Wuchang, Hanyang, and Hankou, the base of Zhang Zhidong＇s late Qing reform in Hubei. Zhang＇s daring urban modernizing efforts replaced the hierarchical structure of the three cities with relatively equal and symbiotic relationships. More importantly, Zhang Zhidong resurrected the concept of shangzhan （commercial warfare）--the idea that China could fight foreign expansion through commercial competition, which Zeng Guofan first used to address Western commercial advancement in the 1860s. This thought enabled Zhang to use the increasing global pressure and Chinese nationalistic sentiments to advance his reform agenda and break from the restrictions of the traditional urban ideal. Analyzing the intellectual foundations of late Qing urban reform is also crucial to understanding cities＇ central position in Qing＇s defensive global engagement.
