Extensively interconnected silicon nanoparticles via carbon network derived from ultrathin cellulose nanofibers as high performance lithium ion battery anodes

Jong Min Kim, Valentina Guccini, Kwang-dong Seong, Jiseop Oh, German Salazar-Alvarez*, Yuanzhe Piao*.

Carbon 118 (2017) 8–17
DOI: 10.1016/j.carbon.2017.03.028

Abstract:
Silicon is a good alternative to conventional graphite anode but it has bad cycling and rate performance. To overcome these severe problems, extensively interconnected silicon nanoparticles using carbon network derived from ultrathin cellulose nanofibers were synthesized. Ultrathin cellulose nanofibers, an abundant and sustainable material, 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 LIBs applications.