The Use of TEMPO-oxidized Nanofibrillated Cellulose as Anode Binder for Lithium-ion Batteries

Abstract

Expansion of the anode coating layer during lithium-ion battery charging and discharging is of significant concern because it can delaminate or break the coating layer, thus critically affecting battery lifespan and the efficiency, especially in silicon-based electrodes. Therefore, control of expansion and improvement of the mechanical properties of the anode layer are essential. Nanofibrillated cellulose (NFC) exhibits excellent network-forming and mechanical properties and have been extensively researched in terms of high-value applications. This study aims to enhance the rheological and mechanical properties of conventional anode layers by using TEMPO-oxidized NFC (TNFC) as the binder. Anode coating processability was investigated through rheological properties, and the interaction mechanisms between TNFC and electrode graphite were explored. Performance changes were examined using tensile and peel tests to assess adhesion between the electrode and copper foil. The tensile properties of an anode with TNFC improved dramatically. The use of TNFC alone as binder reduced the electrode abrasion resistance to copper foil, but this can be countered by combining TNFC with a traditional SBR binder. This study thus highlights the potential of TNFC as novel renewable binders for anodes.