| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF2-ThM |
| Session: | Area-selective Deposition and Sequential Infiltration Synthesis |
| Presenter: | Wenyi Xie, North Carolina State University |
| Authors: | W. Xie, North Carolina State University O.J. Rojas, North Carolina State University S. Khan, North Carolina State University G.N. Parsons, North Carolina State University |
| Correspondent: | Click to Email |
Common thermoplastic polymers, such as polyvinyl alcohol and cellulose derivatives are viable precursors to prepare carbon materials for supercapacitor electrodes. These polymers can be readily processed to prepare high external surface area nanofibers. However, thermoplastic polymers undergo melting transition upon heating, therefore result in loss of initial morphology and low carbon yield. In this study, vapor infiltration of diethyl zinc is applied to modify cellulose based nanofibers as the carbon precursor. Our goal is to investigate the effect of inorganic modification on the morphology, surface area and pore volume, as well as the supercapacitor performance of the carbon product from the modified cellulose based nanofibers.
Vapor infiltration of diethyl zinc (DEZ), was performed using a home-built viscous-flow hot-wall tube reactor. One cycle of the vapor infiltration chemistry consisted of a short dose of DEZ (1 s), followed by a DEZ-hold step (60 s) to enable the reactant to diffuse into the nanofibers, and then followed by a N2 purge step (40 s) to remove excess reactant and byproducts. Scanning electron microscopy (SEM) revealed that the fiber structure of cellulose-based nanofibers could be preserved with at least ~ 8.0 wt % of Zn. Nitrogen sorption measurements at 77 K showed that the surface area and pore volume could be tuned by the DEZ infiltration process. Two-electrode symmetric capacitors were fabricated using the carbon materials from the DEZ modified cellulose based nanofibers. Cyclic voltammetry measurements were performed using 1 M KOH as the electrolyte to determine the specific capacitance. The carbon materials obtained from the DEZ modified cellulose based nanofibers showed a specific capacitance in range of ~25 to 50 F/g.
In this work, vapor infiltration of DEZ has enabled the preparation of carbon nanofibers from cellulose based nanofibers. By varying the loading of Zn, the surface area and pore volume of the resulting carbon nanofibers can be tuned to enhance the supercapacitor performance. Therefore, we believe that inorganic modification by vapor infiltration of DEZ is promising for modifying thermoplastic polymers to produce high performance nanostructured carbon materials for supercapacitors