122nd General Meeting of the KCS

Type Symposium
Area Electrochemical Energy Conversion and Storage: Progress and New Challenges
Room No. Room 320
Time THU 17:20-:
Code ELEC1-5
Subject Interconnected Silicon Nanoparticles via Carbon Network Derived from Cellulose Nanofibers for Lithium Ion Battery Anodes
Authors Yuanzhe Piao
Graduate School of Convergence Science and Technol, Seoul National University, Korea
Abstract The application of nanocellulose-based scaffolds as precursors for electrode materials can result in cost-effective materials. In this work, pyrolysis of three-dimensional wood-based lignocellulosic materials was studied for the preparation of lithium ion battery electrodes with high surface area and adjustable porosity to obtain conductive open networks that show a high electronic conductivity. Preliminary experiments using pyrolysed nanocellulose aerogels have shown that, by increasing the micropore volume and tailoring them to specific electrolytes, higher specific capacitances could be obtained. Ultrathin cellulose nanofibers entangle each silicon nanoparticle and become extensively interconnected carbon network after pyrolysis. This wide range interconnection provides an efficient electron path by decreasing the likelihood that electrons experience contact resistivity and also suppresses the volume expansion of silicon during lithiation. In addition, ultrathin cellulose nanofibers are carboxylated and therefore adhesive to silicon nanoparticles through hydrogen bonding. This property makes ultrathin cellulose the perfect carbon source when making silicon composites. As a consequence, it exhibits 808 mAh g-1 of the reversible capacity after 500 cycles at high current density of 2 A g-1 with a coulombic efficiency of 99.8 %. Even at high current density of 8 A g-1, it shows a high reversible discharge capacity of 464 mAh g-1. Moreover, extensively interconnected carbon network prevents the formation of a brittle electrode with a water-based binder. Therefore, this remarkable material has a huge potential for lithium-ion battery applications.
E-mail parkat9@snu.ac.kr