Study On Nitrogen/Sulfur Co-doped Activated Carbon And Its Application In Flexible Supercapacitor

This article is based on the activated carbon material which is widely used in the field of supercapacitor.In view of the low specific capacitance of activated carbon material,we modified the activated carbon material by simple hydrogen peroxide pretreatment and high temperature annealing doping.While widen the pores of activated carbon,the modification achieves high levels of nitrogen/sulfur atom doping,and improve electrochemical energy storage performance of activated carbon materials.At the same time,the modified activated carbon material was further prepared into printable activated ink.With the help of screen-printing technology,the nitrogen/sulfur co-doped activated carbon based fully printed flexible supercapacitor with excellent electrochemical energy storage performance and mechanical flexibility was finally obtained.The specific research content is as follows:（1）For the nitrogen and sulfur co-doped activated carbon（N/S-HAC）prepared by hydrogen peroxide pre-oxidation and high temperature annealing,the two-step reaction is not a simple process superposition.Hydrogen peroxide pretreatment introduced a large number of oxygen-containing functional groups into the activated carbon,and the high activity of these oxygen-containing functional groups greatly promoted the process of nitrogen and sulfur co-doped and channel expansion in the annealing process.（2）Nitrogen and sulfur co-doped activated carbon（N/S-HAC）has excellent energy storage performance.At the current density of 0.5 A g^-1,the specific capacitance of N/S-HAC reaches 175 F g^-1,which is more than twice that of the original commercial activated carbon AC(80 F g^-1).At the same time,N/S-HAC also has excellent rate capability.When the current density of the electrode increases 200 times,its capacitance still maintains 70%,which is higher than 60%of the original commercial activated carbon AC.（3）Using screen-printing technology,N/S-HAC based fully printed flexible supercapacitor with both energy storage performance and mechanical flexibility was prepared.When the current density is 2 mA cm^-2,the area ratio capacitance of N/S-HAC based flexible supercapacitor is up to 100 mF cm^-2,and when the current density increases by 40 mA cm^-2,the specific capacitance can still maintain 83%.The N/S-HAC device has a maximum power density of 28 mW cm^-2,a maximum energy density of 0.0271 mWh cm^-2,and a high capacitance retention rate of 90%after 20,000 charge-discharge cycles.At the same time,N/S-HAC based flexible supercapacitor also showed excellent flexibility in multi-angle bending test and 1000 bending cycle test.（4）Design and assemble flexible supercapacitor array and a set of integrated light-emitting T-shirt.The device can work stably in the process of bending or moving,which fully demonstrates the excellent integration ability of N/S-HAC based flexible supercapacitor and broad application prospect in wearable field.