Aqueous Zn//MnO2 batteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness,high safety,high output voltage,and energy density.However,the MnO2 cathode suffers from intrin...Aqueous Zn//MnO2 batteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness,high safety,high output voltage,and energy density.However,the MnO2 cathode suffers from intrinsically poor rate performance and rapid capacity deterioration.Here,we remove the roadblock by compositing MnO2 nanorods with highly conductive graphene,which remarkably enhances the electrochemical properties of the MnO2 cathode.Benefiting from the boosted electric conductivity and ion diffusion rate as well as the structural protection of graphene,the Zn//MnO2-graphene battery presents an admirable capacity of 301 mAh g^-1 at 0.5 A g^-1,corresponding to a high energy density of 411.6 Wh kg^-1.Even at a high current density of 10 A g^-1,a decent capacity of 95.8 mAh g^-1 is still obtained,manifesting its excellent rate property.Furthermore,an impressive power density of 15 kW kg^-1 is achieved by the Zn//MnO2-graphene battery.展开更多
γ-MnO2 nanorod-assembled hierarchical micro-spheres with abundant oxygen defects are synthesized by a simple thermal treatment approach as oxygen reduction electrocatalysts for Al(aluminum)-air batteries. The rich ox...γ-MnO2 nanorod-assembled hierarchical micro-spheres with abundant oxygen defects are synthesized by a simple thermal treatment approach as oxygen reduction electrocatalysts for Al(aluminum)-air batteries. The rich oxygen vacancies on the surface of γ-MnO2 are verified by morphology, structure,electron paramagnetic resonance(EPR) and X-ray photoelectron spectroscopy(XPS) results. The oxygen reduction reaction(ORR) electrocatalytic activity of γ-MnO2 is significantly improved by the incoming oxygen vacancies. The γ-MnO2 nanorod-assembled hierarchical micro-spheres calcined under 300 °C in Ar atmosphere show the best ORR performance. The primary Al-air batteries using γ-MnO2 catalysts as the cathode, which demonstrates excellent peal power density of 318 m W cm^(-2) when applying theγ-MnO2 catalysts with optimal amount of oxygen vacancies.展开更多
The MXenes,a new class of two-dimensional layered materials,have found extensive applications in water treatment for its excellent thermal stability,electrical conductivity,and excellent adsorption ability.Sulfidized ...The MXenes,a new class of two-dimensional layered materials,have found extensive applications in water treatment for its excellent thermal stability,electrical conductivity,and excellent adsorption ability.Sulfidized nano zero-valent iron(S-nZVI)is a good reducing agent,however,the practical application of S-nZVI is currently restricted due to the tendency of nano materials to agglomerate.Herein,MXenes use as a support and in situ loading S-nZVI on it to prepare a new material(S-nZVI/Ti_(3)C_(2)T_(x)),and applied it to U(VI)removal in water treatment.The microscopic characterization proves that S-nZVI on Ti_(3)C_(2)T_(x) has good dispersion and effectively alleviates agglomeration.Batch experiments shown that SnZVI/Ti_(3)C_(2)T_(x) has a very good effect on U(VI)removal,and themaximumadsorption capacity reaches 674.4mg/g under the aerobic condition at pH=6.0.The pseudo-second-order kinetic model and the Langmuir isotherm model were found to be more appropriate for describing the adsorption behavior.This indicates that the removal process is a single molecular layer chemisorption.Moreover,the S-nZVI/Ti_(3)C_(2)T_(x) maintained a removal efficiency of over 85%for U(VI)even after being reused five times,demonstrating its excellent reusability.It is worth noting that the material can remove 79.8%of 50 mg/L of U(VI)in simulated seawater,indicating that S-nZVI/Ti_(3)C_(2)T_(x) possessed an excellent uranium extraction performance from seawater.Experimental results and XPS analysis showed that U(VI)was removed by adsorption,reduction and co-precipitation.Moreover,S-nZVI/Ti_(3)C_(2)T_(x) was a lowtoxicitymaterial to Hyriopsis cumingii.Therefore,S-nZVI/Ti_(3)C_(2)T_(x) was expected to be a candidate as adsorbent with great potential in removal of uranium from wastewater and seawater.展开更多
基金financially supported by the Guangdong Power Grid Co.,Ltd.(Grant No.GDKJXM20160000)。
文摘Aqueous Zn//MnO2 batteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness,high safety,high output voltage,and energy density.However,the MnO2 cathode suffers from intrinsically poor rate performance and rapid capacity deterioration.Here,we remove the roadblock by compositing MnO2 nanorods with highly conductive graphene,which remarkably enhances the electrochemical properties of the MnO2 cathode.Benefiting from the boosted electric conductivity and ion diffusion rate as well as the structural protection of graphene,the Zn//MnO2-graphene battery presents an admirable capacity of 301 mAh g^-1 at 0.5 A g^-1,corresponding to a high energy density of 411.6 Wh kg^-1.Even at a high current density of 10 A g^-1,a decent capacity of 95.8 mAh g^-1 is still obtained,manifesting its excellent rate property.Furthermore,an impressive power density of 15 kW kg^-1 is achieved by the Zn//MnO2-graphene battery.
基金supported by the National Natural Science Foundation of China (21975163, 51902204)。
文摘γ-MnO2 nanorod-assembled hierarchical micro-spheres with abundant oxygen defects are synthesized by a simple thermal treatment approach as oxygen reduction electrocatalysts for Al(aluminum)-air batteries. The rich oxygen vacancies on the surface of γ-MnO2 are verified by morphology, structure,electron paramagnetic resonance(EPR) and X-ray photoelectron spectroscopy(XPS) results. The oxygen reduction reaction(ORR) electrocatalytic activity of γ-MnO2 is significantly improved by the incoming oxygen vacancies. The γ-MnO2 nanorod-assembled hierarchical micro-spheres calcined under 300 °C in Ar atmosphere show the best ORR performance. The primary Al-air batteries using γ-MnO2 catalysts as the cathode, which demonstrates excellent peal power density of 318 m W cm^(-2) when applying theγ-MnO2 catalysts with optimal amount of oxygen vacancies.
基金supported by the National Natural Science Foundation of China(No.42277063)the Postdoctoral Research Foundation of China(No.2021M702886)+1 种基金the Leading Innovative Talents cultivation Project of Changzhou City(No.CQ20230096)the Research Initiation Project of Changzhou University.
文摘The MXenes,a new class of two-dimensional layered materials,have found extensive applications in water treatment for its excellent thermal stability,electrical conductivity,and excellent adsorption ability.Sulfidized nano zero-valent iron(S-nZVI)is a good reducing agent,however,the practical application of S-nZVI is currently restricted due to the tendency of nano materials to agglomerate.Herein,MXenes use as a support and in situ loading S-nZVI on it to prepare a new material(S-nZVI/Ti_(3)C_(2)T_(x)),and applied it to U(VI)removal in water treatment.The microscopic characterization proves that S-nZVI on Ti_(3)C_(2)T_(x) has good dispersion and effectively alleviates agglomeration.Batch experiments shown that SnZVI/Ti_(3)C_(2)T_(x) has a very good effect on U(VI)removal,and themaximumadsorption capacity reaches 674.4mg/g under the aerobic condition at pH=6.0.The pseudo-second-order kinetic model and the Langmuir isotherm model were found to be more appropriate for describing the adsorption behavior.This indicates that the removal process is a single molecular layer chemisorption.Moreover,the S-nZVI/Ti_(3)C_(2)T_(x) maintained a removal efficiency of over 85%for U(VI)even after being reused five times,demonstrating its excellent reusability.It is worth noting that the material can remove 79.8%of 50 mg/L of U(VI)in simulated seawater,indicating that S-nZVI/Ti_(3)C_(2)T_(x) possessed an excellent uranium extraction performance from seawater.Experimental results and XPS analysis showed that U(VI)was removed by adsorption,reduction and co-precipitation.Moreover,S-nZVI/Ti_(3)C_(2)T_(x) was a lowtoxicitymaterial to Hyriopsis cumingii.Therefore,S-nZVI/Ti_(3)C_(2)T_(x) was expected to be a candidate as adsorbent with great potential in removal of uranium from wastewater and seawater.
