Lignin-based carbon mats – promising electrodes of supercapacitors from wood

Lignin is one of the major renewable sources which can be obtained from the forest, however, about 98% of lignin from pulping and papermaking industry has been wasted or simply burnt. Recent studies show that lignin can be spun and converted to carbon fibers of high quality due to its abundant phenolic structure. Moreover, electrospinning as a state-of-art process can be applied to produced lignin-based nanofiber mats, which gives the fiber mats significantly high specific surface area. Together with carbonization process, the lignin-based carbon mats are attractive to be used as electrodes in supercapacitors for energy saving and storage. In this study, lignin/poly(vinyl alcohol)-based fiber mats with very high lignin content (75 wt%) are prepared via electrospinning and the as-spun mats are carbonized at different temperatures up to 1400 °C. The fiber networks obtained from electrospinning remains intact after the carbonization process, which guarantees their outstanding specific surface areas as high as 1700 m2/g. Furthermore, the electrochemical measurements of the carbonized mats indicate that a superior specific capacitance of 241 F/g are reached compared with most of the literature-reported values, which shows that the lignin-based carbon mats have great potential to replace electrodes from fossil-based and/or unrenewable materials