Preparation and formation mechanism of size-controlled lignin based microsphere by reverse phase polymerization

Abstract Commercial lignin, by-product of enzymatic hydrolysis of biomass for bioethanol production, was used to prepare lignin based microsphere by reverse phase polymerization. The reverse phase polymerization had favorable influence on the morphology, size distribution and thermal stability by coordinating solid content and dispersed phase content of lignin emulsion. The carbonization yield at 870 °C of lignin based microsphere reaches to 38.87% by improving 5% from lignin precursor 33.43%, at solid content 0.059 and dispersed phase content 0.050. The mechanism is postulated based on the results from elemental analysis, FT–IR spectroscopy and thermogravimetric analysis. Furthermore, the lignin based microsphere could directly carbonize without pre-oxidization process. Hence, the reverse phase polymerization is a meaningful and possible industrial process. And the gravimetric capacitance of lignin based activated carbon microsphere (LAC-M) is as high as 334 F g −1 , and even after 10,000 cycles at 1 A g −1 a specific capacity of 286 F g −1 remains. Thus, LAC-M is a promising material for high performance SCs.