BAE Seminar, Tuesday, April 29, 2014

Please join us for the weekly BAE seminar 

Tuesday, April 29, 2014 
3:10 4 pm 

Topic: Preparation of activated carbon particulates and fibers from lignin and its application as electric supercapacitors 

Presenter: Sixiao Hu 
PhD Student, Agricultural and Environment Chemistry 

High carbon content and highly crosslinked polypropanoid structure of lignin make it ideal precursor to various carbon materials. Lignin has been thermally processed into graphitic carbon fibers with excellent mechanical properties, however at temperature exceeding 2000 oC, thus very costly. Converting lignin to non-graphitic porous carbons, on the other hand, could be achieved at much lower temperatures of less than 1000 oC. This paper focused on the fabrication of chemically activated carbon fiber (ACFs) and activated carbon particulate (ACP) from low-sulfonated alkali lignin. Water-soluble lignin was dissolved in aqueous alkali hydroxide then dried into ACP precursor, or mixed with a small amount of polyethylene oxide (PEO) and electrospun into ACF precursor. Both precursors were simultaneously carbonized and activated into porous carbon particles and fibers in one fast single step. The obtained ACPs and ACFs exhibited very high specific surface (up to~1500 m2/g BET surface area) and pore volume (single point pore volume up to 0.9 cm3/g). Electric supercapacitors assembled from either ACPs or ACFs exhibited excellent capacitance, power and energy density up to 344 F/g, 3 kW/kg and 8.1 Wh/kg respectively. Such performances were superior to graphene and carbon nanotubes based counterparts. The electrochemical properties of the ACP and ACF based supercapacitors were strongly dependent on the composition, size and defects of the basal plane and amorphous sp2 carbon, as well as pore size and structures, all could be essentially controlled by amounts and types of alkali hydroxides, carbonization temperature and heating time. 

Sixiao Hu received his BE degree in Polymeric Material Science and Engineering from Donghua University in Shanghai, China where he was awarded national scholarship twice and an honor undergraduate thesis. He then pursued his PhD degree in Agricultural and Environmental Chemistry at UC-Davis with Dr. You-Lo Hsieh. He was awarded the Grand Prize of Graduate Student Research Competition by the National Textile Center as well as a Travel Award and Excellence in Graduate Polymer Research by the Polymer Division of the American Chemical Society for his works on utilization of lignocellulosic biomasses. His research includes three major areas: (1) preparation of activated carbon particulates and fibers from lignin and its application as electric supercapacitors; (2) synthesis of silver nanoparticles using lignin in solution and on solid cellulose substrate; (3) preparation of activated carbon and silica particles from rice straw extracts. 

Coffee and cookies will be served.