(65f) Silicon-Rich Carbon Nanofibers From Water-Based Spinning to Control Combination of Silicon and Carbon for Li-Ion Battery

Silicon-rich carbon nanofibers from water-based spinning to control combination of silicon and carbon for Li-ion battery

Yong Seok Kim, Kyoung Woo Kim, Daehwan Cho, Nathaniel S. Hansen, and Yong Lak Joo*

School of Chemical and Biomolecular Engineering, Cornell University, Ithaca 14853, USA

ABSTRACT: Carbon (C) nanofibers with high silicon (Si) loading (> 65 wt%) were fabricated from water–based electrospinning of aqueous polyvinyl alcohol/Si nanoparticle solution for Li–ion battery anode applications. Our Si-rich C (SRC) nanofibers showed much facilitated charge transport features and increased activities because of continuous one–dimensional (1–D) carbon backbone structure, leading to superior battery performance to that of bare silicon nanoparticles. The presence of carbon as 1–D nanofibers could not only mitigate volume expansion of silicon but also avoid formation unstable solid electrolyte interface onto the surface of silicon. Our study on the optimum combination of carbon and silicon in the nanofibers for their electrochemical properties and battery performance revealed that the SRC nanofibers with 72.8 wt% Si content (27.2 wt% C) exhibits an adequate balance between high energy capacity of Si nanoparticles and dimensional stability with effective charge transport by carbon nanofibers, leading to an outstanding cycle life to maintain 1076 mAh/g normalized by total electrode mass and high Coulombic efficiency of about 99% for fifty cycles. Such scalable Si-rich C nanofibers made from water-based electrospinning using polyvinyl alcohol should be greatly contributed to a cost–effective development of high performance negative battery electrodes.