A Dry-Mechanical Approach for Scrap Recycling of Dry-Processed Lithium Ion Battery Cathodes

Abstract

Dry electrode processing using polytetrafluoroethylene (PTFE) as binder is promising for the manufacturing of lithium ion battery cathodes, as it eliminates energy- and cost-intensive solvent evaporation and recovery. Above-average scrap rates are expected due to production optimization, ramp-up, and extensive trimming of rough electrode film edges after granules calendering, which renders direct recycling of in-production scrap industrially relevant. This work demonstrates an approach for a dry-mechanical, scalable, non-toxic, and profitable delamination and granulation process sequence. The low adhesive forces of the PTFE-based composite to the current collector enable a mechanical non-destructive recovery of the composite via mild milling, where even the secondary particle structure of the cathode active material (CAM) and the PTFE fibril network remain intact. The granule size in the composite is shown to be restored via tuning the cutting mill time. Finally, electrodes from recycled composite exhibit similar electrochemical properties as from pristine composite. According to a life cycle cost assessment (LCCA) for an exemplary scrap rate of 5% and LiNi0.8Co0.1M0.1O2 as CAM, $0.8 per kWh can be saved, representing 2.6% of the total electrode processing cost.