Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response me...Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.展开更多
This article studies the role of electrochemical parameters in controlling the morphology of oxidized TiO_(2)nanotubes and the electrochemical performance of modified TiO_(2)nanotubes.Humidity is a key factor for fabr...This article studies the role of electrochemical parameters in controlling the morphology of oxidized TiO_(2)nanotubes and the electrochemical performance of modified TiO_(2)nanotubes.Humidity is a key factor for fabricating TiO_(2)nanotubes.When the relative humidity belows 70%,the TiO_(2)nanotubes can be successfully prepared.What's more,by changing the anodization voltage and time,the diameter and the length of TiO_(2)nanotubes can be adjusted.In addition,the TiO_(2)nanotubes are modified through electrochemical self-doping and loading Pt metal particles on the surface of the nanotubes,which promotes the performance of the supercapacitor.The sample anodized at 100 V for 3 h has a specific capacity of up to 2.576 mF/cm~2 at a scan rate of 100 mV/s after self-doping,and its capacity retention rate still remains at 89.55%after 5000 cycles,demonstrating excellent cycling stability.The Pt-modified sample has a specific capacity of up to 3.486 mF/cm~2 at the same scan rate,exhibiting more outstanding electrochemical performance.展开更多
文摘Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.
基金National Natural Science Foundation of China(No.12004070)。
文摘This article studies the role of electrochemical parameters in controlling the morphology of oxidized TiO_(2)nanotubes and the electrochemical performance of modified TiO_(2)nanotubes.Humidity is a key factor for fabricating TiO_(2)nanotubes.When the relative humidity belows 70%,the TiO_(2)nanotubes can be successfully prepared.What's more,by changing the anodization voltage and time,the diameter and the length of TiO_(2)nanotubes can be adjusted.In addition,the TiO_(2)nanotubes are modified through electrochemical self-doping and loading Pt metal particles on the surface of the nanotubes,which promotes the performance of the supercapacitor.The sample anodized at 100 V for 3 h has a specific capacity of up to 2.576 mF/cm~2 at a scan rate of 100 mV/s after self-doping,and its capacity retention rate still remains at 89.55%after 5000 cycles,demonstrating excellent cycling stability.The Pt-modified sample has a specific capacity of up to 3.486 mF/cm~2 at the same scan rate,exhibiting more outstanding electrochemical performance.
