Porous structure-tuned cellulose nanofiber paper separators (designated as S-CNP separators) are demonstrated as a promising alternative to commercial polyolefin separators for use in lithium-ion batteries. A new architectural strategy based on colloidal silica (SiO2) nanoparticle-assisted structural control is presented to overcome the difficulty in forming controllable porous structure of pure cellulose nanofiber paper separators (designated as CNP separators) from densely-packed cellulose nanofibers (CNFs). The new S-CNP separators proposed herein incorporate SiO2 nanoparticles as a CNF-disassembling agent (i.e., as non-conductive spacer particles). This structural uniqueness allows loose packing of CNFs, thereby facilitating the evolution of more porous structure. The unusual porous structure of S-CNP separators can be fine-tuned by varying SiO2 contents in the CNF suspension. Notably, the S-CNP separator (fabricated with 5 wt.% SiO2 content) exhibits the highest ionic conduction due to the well-balanced combination of nanoporous structure and separator thickness, thus contributing to excellent cell performance. This study underlines that the colloidal SiO2 nanoparticle-directed structural tuning of CNPs offers a promising route for the fabrication of advanced paper separators with optimized attributes and functionality.
Bibliographical noteFunding Information:
This work was supported by the Korea Forest Research Institute FP 0400-2007-03 grant. This work was also supported by the leading industry of Sustainable Energy of the Chungcheong Leading Industry Office of the Korean Ministry of Knowledge Economy.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering