摘要
Activated carbon(AC)has attracted tremendous research interest as an electrode material for supercapacitors owing to its high specific surface area,high porosity,and low cost.However,AC-based supercapacitors suffer from limited rate performance and low power density,which mainly arise from their inherently low electrical conductivity and sluggish ion dynamics in the micropores.Here,we propose a simple yet effective strategy to address the aforementioned issue by nitrogen/fluorine doping and enlarging the micropore size.During the treatment,the decomposition products of NH4F react with the carbon atoms to dope the AC with nitrogen/fluorine and simultaneously enlarge the pores by etching.The treated AC shows a higher specific surface area of 1826 m2 g^(−1)(by~15%),more micropores with a diameter around 0.93 nm(by~33%),better wettability(contact angle decreased from 120°to 45°),and excellent electrical conductivity(96 S m^(−1))compared with untreated AC(39 S m^(−1)).The as-fabricated supercapacitors demonstrate excellent specific capacitance(26 F g^(−1)at 1 A g^(−1)),significantly reduced electrical resistance(by~50%),and improved rate performance(from 46.21 to 64.39%at current densities of 1 to 20 A g^(−1)).Moreover,the treated AC-based supercapacitor achieves a maximum energy density of 25 Wh kg^(−1)at 1000 W kg^(−1)and a maximum power density of 10,875 W kg^(−1)at 15 Wh kg^(−1),which clearly outperforms pristine AC-based supercapacitors.This synergistic treatment strategy provides an effective way to improve the rate performance and power density of AC-based supercapacitors.
基金
supported by Royal Society Newton Advanced Fellowship(Nos.52061130218,NAF\R1\201127)
the State Key Laboratory of Clean Energy Utilization Open Fund(No.ZJUCEU2019002).
作者简介
Jian Zhang,contributed equally;Huachao Yang,contributed equally;Zheng Bo,bozh@zju.edu.cn。
