蔗糖溶液制备微/介孔炭球及其电容性能

Micro/mesopore carbon spheres derived from sucrose for use in high performance supercapacitors

以蔗糖溶液为炭前驱体,通过简单的水热炭化和KOH/NaOH碱活化方法制备微/介孔炭球。研究了KOH和NaOH活化参数对炭球比表面积和相应孔径分布的影响。炭球作为超级电容器电极,在6 mol L^(−1) KOH电解液中具有高的比电容和良好的倍率性能。此外,在1 mol L^(−1) MeEt_(3)NBF_(4)/PC有机电解液中,微/介孔炭球电极组成的对称电容器表现出高达30.4 Wh kg^(−1)的能量密度和18.5 kW kg^(−1)的功率密度。在5 A g^(−1)的电流密度下,充放电循环15000次后比容量保持率为73.0%。

Micro/mesopore carbon spheres for use as the electrode materials of supercapacitors were prepared by hydrothermal carbonization followed by KOH/NaOH activation using sucrose as the carbon precursor.The effects of the KOH and NaOH activation parameters on the specific surface area,pore size distribution and electrochemical performance of the carbon spheres were investigated.Results indicate that the use of NaOH leads to the development of mesopores while the use of KOH increases the specific surface area and micropore volume.The pore size distribution of carbon spheres could be adjusted by varying the relative amounts of the reagents in the activation.Using a NaOH/KOH mass ratio of 2∶1 and a reagent/carbon sphere mass ratio of 3∶1,a good capacitance and rate performance of the supercapacitor electrode in both a 6 mol L^(−1) KOH aqueous electrolyte and a 1 mol L^(−1) MeEt_(3)NBF_(4)/propylene carbonate electrolyte was achieved.The prepared activated carbon gave a capacitance of 235 F g^(−1) at 0.1 A g^(−1) and a capacitance retention of 81.5%at 20 A g^(−1) in the 6 mol L^(−1) KOH aqueous electrolyte,and in a cell using the 1 mol L^(−1) MeEt_(3)NBF_(4)/propylene carbonate electrolyte,it gave the highest energy density of 30.4 Wh kg^(−1) and a power output of 18.5 kW kg^(−1).