Ni/MnO2 doping pulping lignin-based porous carbon as supercapacitors electrode materials

Lignin extracted from pulping black liquor as carbon source, C4H6O4Ni center dot 4H(2)O as acatalyst and KMnO4 as dopant, a lignin-based porous carbon material (PC-Ni/MnO2) co-doped with Ni and MnO2 was prepared and used in electrode materials for supercapacitors. During the high-temperature carbonization process, part of amorphous carbon generates a multi-layer graphene structure, causing the PC-Ni/MnO2 to has a high degree of graphitization. Meanwhile, KMnO4 gradually decomposes and reacts with C to produce MnO2. The lignin-based porous carbon material has a higher pseudocapacitance, the specific capacitance of PC-Ni/ MnO2 can reach 267.34 F g(-1) at a current density of 0.1 A g(-1). After 5 000 cycles charge and discharge test, the specific capacitance retention rate kept 83.6% at a current density of 1 A g(-1), showing good rate performance and electrochemical stability. A symmetrical supercapacitor prepared by PC-Ni/MnO2 as electrodes, its energy density can reach 28 Wh.kg(-1) as the power density of the capacitor is 360 W kg(-1). And the supercapacitor also exhibited good cyclic stability with 86.3% retention of initial capacitance after 5000 cycles at 1.0 A g(-1). When two such supercapacitors in series, a LED lamp can be light. These induct that the doping of Ni and MnO2 can improve the capacitance characteristics, showing that the biomass porous carbon has great practical application value. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, a lignin-based porous carbon material (PC-Ni/MnO2) co-doped with Ni and MnO2 was prepared and used in electrode materials for supercapacitors. The doping of Ni and MnO2 improved the capacitance characteristics, showing good rate performance and electrochemical stability. The biomass porous carbon has great practical application value in energy storage devices.