Lignin-derived porous carbons via nitrogen-enhanced activation for efficient supercapacitors

Lignin, an abundant industrial by-product, has gained attention as a sustainable precursor for porous carbon electrodes in supercapacitors due to its intrinsic aromaticity and high carbon content. While nitrogen doping is known to enhance electrochemical properties, its impact on lignin char activat...

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Detalles Bibliográficos
Autores: Yi, Minghao, Budarin, Vitaliy, Yue, Hangbo, Tajuelo-Castilla, Guillermo, Morales, Enrique, Ellis, Gary James, Shuttleworth, Peter S.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/397789
Acceso en línea:http://hdl.handle.net/10261/397789
https://api.elsevier.com/content/abstract/scopus_id/105010846771
Access Level:acceso abierto
Palabra clave:Lignin
Microwave solvothermal treatment
Nitrogen-enhanced activation
Porous carbon
Supercapacitor
Descripción
Sumario:Lignin, an abundant industrial by-product, has gained attention as a sustainable precursor for porous carbon electrodes in supercapacitors due to its intrinsic aromaticity and high carbon content. While nitrogen doping is known to enhance electrochemical properties, its impact on lignin char activation mechanisms and porosity development remains underexplored. This study reports a novel, microwave-assisted nitrogen doping strategy using ethanolamine, followed by optimised chemical activation leading to the formation of highly porous carbons with enhanced charge storage capabilities. The activated carbon synthesised at an optimal NaOH-to-char weight ratio of 3:1 exhibits a uniformly distributed pore structure, as confirmed by scanning electron microscopy (SEM), along with a high specific surface area of 2749 m2 g-1 and a pore volume of 1.48 cm3 g-1. Elemental Analysis, Raman spectroscopy, and X-ray Photoelectron Spectroscopy provides information on the thermal transformation of nitrogen species upon pyrolysis, and their differential roles in the activation process. Partial least squares (PLS) analysis further confirms that nitrogen functionality loss and activator dosage both govern porosity development. Electrochemical testing using a 2 M H2SO4 electrolyte demonstrates a high specific capacitance of 292 F g-1 at 0.1 A g-1, a remarkable capacitance retention of 90 % after 4000 cycles at 2 A g-1, and an energy density of 9.2 Wh kg-1 at a power density of 1.1 kW kg-1. These results further establish nitrogen-enhanced NaOH activation as an effective route for tailoring porosity and enhancing electrochemical performance, offering a sustainable pathway for the revalorization of lignin into high-performance supercapacitor electrode materials.