Carbon with Expanded and Well-Developed Graphene Planes Derived Directly from Condensed Lignin as a High-Performance Anode for Sodium-Ion Batteries

Abstract

In this study, we demonstrate that lignin, which constitutes 30-40 wt % of the terrestrial lignocellulosic biomass and is produced from second generation biofuel plants as a cheap byproduct, is an excellent precursor material for sodium-ion battery (NIB) anodes. Because it is rich in aromatic monomers that are highly cross-linked by ether and condensed bonds, the lignin material carbonized at 1300 °C (C-1300) in this study has small graphitic domains with well-developed graphene layers, a large interlayer spacing (0.403 nm), and a high micropore surface area (207.5 m g). When tested as an anode in an NIB, C-1300 exhibited an initial Coulombic efficiency of 68% and a high reversible capacity of 297 mA h g at 50 mA g after 50 cycles. The high capacity of 199 mA h g at less than 0.1 V with a flat voltage profile and an extremely low charge-discharge voltage hysteresis (<0.03 V) make C-1300 a promising energy-dense electrode material. In addition, C-1300 exhibited an excellent high-rate performance of 116 mA h g at 2.5 A g and showed stable cycling retention (0.2% capacity decay per cycle after 500 cycles). By comparing the properties of the lignin-derived carbon with oak sawdust-derived and sugar-derived carbons and a low-temperature carbonized sample (900 °C), the reasons for the excellent performance of C-1300 were determined to result from facilitated Na-ion transport to the graphitic layer and the microporous regions that penetrate through the less defective and enlarged interlayer spacings.

Lignin‐derived electrochemical energy materials and systems

“…Typical carbon materials from lignin: (a) Schematic pathway for the synthesis of nitrogen‐doped mesoporous carbon from beech wood lignin; (b) schematic illustration of the preparation of lignin‐derived carbon‐sheet aerogel and carbon‐fiber aerogel; (c) Field emission scanning electron microscope (FESEM) images of electrospun nanofibers from lignin; (d) TEM images of carbon with expanded and well developed graphene planes derived directly from condensed lignin …”

“…The development of a more efficient, lower cost, and more sustainable approach for large‐scale graphene production is urgently required. The synthesis of graphene from renewable and abundant biomass feedstocks using simple pyrolysis reactions has therefore been proposed and is regarded as a promising route, especially considering the unique polymeric structure of lignin, which is comprised of aromatic rings and condensed linkages and shows great similarity to the hexagonal structure of graphene, which makes it an excellent precursor for producing graphene and graphene‐like materials . Some valuable studies on graphene and graphene‐like carbon materials derived from biomass lignin have been reported .…”

“…There are three typical synthesis routes from lignin to graphene, including: (i) Catalytic graphitization with transitional metals/metal salt catalysts; (ii) direct carbonization in an inert atmosphere; and (iii) a two‐step route involving oxidative cleavage and aromatic refusion . Among these, catalytic graphitization is the most widely used synthesis route for lignin‐derived graphene materials.…”

“…It has also been reported that graphene‐encapsulated metal nanoparticles have been fabricated from lignin through a thermal treatment process under an argon atmosphere with Ni, Cu, Fe, and Mo catalysts . Small graphitic domains with well‐developed graphene layers and a high surface area of 207.5 m 2 g −1 , and 3D graphene and graphene‐like porous carbon were synthesized by the direct carbonization of lignin at a high temperature of 1300 °C . The graphene materials fabricated from lignin by hydrothermal reaction and other supporting steps exhibited a glass‐like microcrystal structure that was chemically bonded by sp carbon atoms .…”

“…In particular, lignin, representing up to 40% of the weight of trees and other lignocellulosic biomass, comprises a cheap and non‐toxic group of phenolic polymers composed of phenyl skeletons and oxygen‐containing branches, the largest natural source of aromatics, and one of the most abundant byproducts of the papermaking industry and biorefineries . Due to its unique polymeric structure, lignin is an excellent carbonaceous precursor for producing high‐performance carbon materials such as graphene . Meanwhile, direct lignin‐based materials without carbonization also exhibit electrochemical activity due to the formation of redox‐active quinone / hydroquinone (Q/QH 2 ) structures from the inside phenol groups .…”