Abstract:
Corn straw enzymatic hydrolyzed lignin carbon LC
1, LC
2and LC
3 were prepared using purified corn straw enzymatic hydrolyzed lignin as carbon source and carbonized at high temperature under N
2 conditions for 1, 2 and 3 h. SEM, TEM and nitrogen adsorption/desorption curve were used to analyze the prepared carbon materials. The results showed that LC
1, LC
2 and LC
3 had microporous, mesoporous and macroporous structures with specific surface areas of 894.75, 1 376.74 and 776.47 m
2/g, respectively. The pore volumes of the samples were 0.41, 0.70 and 0.40 cm
3/g, respectively. XRD and Raman spectrum showed that the order of the enzymatic hydrolyzed lignin carbon increased with the prolongation of carbonization time. XPS analysis showed that the enzymatic hydrolyzed lignin carbon mainly contained C, O and N(small amount) elements. The electrochemical properties of LC
1, LC
2 and LC
3 were tested using a three-electrode system. The results showed that LC
2 had the highest specific capacitance of 222.2 F/g at 0.2 A/g current density, and the specific capacitance of LC
2 reached 149 F/g at higher current density of 20 A/g. Further study on its practical application in supercapacitors, the results showed that LC
2 assembled symmetric supercapacitor had the largest specific capacitance per electrode and the highest capacitance retention(70.2%). At 1 A/g current density, the LC
2 supercapacitor showed good rate performance and electrochemical stability after 5 000 charge-discharge cycles. Moreover, a series battery composed of symmetric LC
2 supercapacitor could directly light the LED lamp.