Lignin-based carbon fibers for renewable and multifunctional lithium-ion battery electrodes

Abstract

Lignin-based carbon fibers (LCFs) from the renewable resource softwood kraft lignin were synthesized via oxidative thermostabilization of pure melt-spun lignin and carbonization at different temperatures from 1000°C to 1700°C. The resulting LCFs were characterized by tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD) and confocal Raman spectroscopy. The microstructure is mainly amorphous carbon with some nanocrystalline domains. The strength and stiffness are inversely proportional to the carbonization temperature, while the LCFs carbonized at 1000°C exhibit a strength of 628 MPa and a stiffness of 37 GPa. Furthermore, the application potential of LCFs was evaluated as negative electrodes in a lithium-ion battery (LIB) by electrochemical cycling at different current rates in a half-cell setup. The capacity drops with the carbonization temperature and the LCFs carbonized at 1000°C have a capacity of 335 mAh g−1. All LCFs showed good cycling stability. Because of the mechanical integrity and conductivity of the LCFs, there is no need to apply current collectors, conductive additives or binders. The advantage is an increased gravimetric energy density compared to graphite, which is the most common negative electrode material. LCFs show a promising multifunctional behavior, including good mechanical integrity, conductivity and an ability to intercalate lithium for LIBs.

Bio‐derived Carbon Nanofibres from Lignin as High‐Performance Li‐Ion Anode Materials

“…To furtheri nvestigate the best-performing PLA-derived nanofibres (i.e.,5 0:50 and 70:30), rate capability testing was nitrogen-doped 1150 [21] PPy precursor,650 8Ca ctivation0.01-3.0 600 943 [29] electrospun from PAN0-2.8 1450 [32] multifilament 0-1.6 3320 melt-spinning [33] PEO and lignin electrospinning 0-3 50 576 [34] pyrolysis and carbonisation of lignin 0.005-1.5 65 340 [20] electrospun from PANa nd DMF 0-3 500 333…”

“…CNFs produced by electrospinning can be incorporated into the commercial production of LIBs owing to their lower cost (compared with CNTsorg raphene) and the possibility of producing electrodes with large areas. [32][33][34][35][36] In the presents tudy,w eh ave developed fully sustainable CNFs with differing tailoredm icrostructures by using lignin blended with two biobased polymers, at hermoplastic elastomer polyurethane (TPU) and polylactic acid (PLA). PANi sapetroleumbased polymerw ith serious drawbacks such as high production cost and environmental issues associated with high CO 2 emissions and solvent usage during synthesis.…”

Are lignin-derived carbon fibers graphitic enough?

“…4. [35][36][37] Unfortunately, the aforementioned statements regarding the lack of graphitic structure in lignin-derived CFs cannot be confidently validated due to a lack of published data showing evidence of such. However, there is an emerging field of research targeting the development of new methods to convert lignin and other bioresources into graphite for electrochemical applications, such as anodes for Li-ion batteries.…”

“…However, there is an emerging field of research targeting the development of new methods to convert lignin and other bioresources into graphite for electrochemical applications, such as anodes for Li-ion batteries. 35,[38][39][40][41][42][43][44][45] The lignin graphitization procedures used in these studies are similar to those used in carbon fiber studies, with the major exception being that strength properties are not optimized since electrode applications do not require such. Instead, lignin graphitization studies optimize for graphitic structure formation, and usually small graphitic particles are produced, not fibers.…”

Alternatives for Chemical and Biochemical Lignin Valorization: Hot Topics from a Bibliometric Analysis of the Research Published During the 2000–2016 Period

“…Besides, more advanced applications have been discovered for lignin-based carbons: their properties make them valuable materials for components in electronic devices. The development of electrodes with outstanding performance just by simple fabrication processes is very promising for future energy-storage systems and sensors [475][476][477][478].…”