Additive Influence on Binder Migration in Electrode Drying

Two main goals for the industrial, slurry-based electrode processing are a high process speed and the maximum possible material efficiency. This makes an increased drying rate and active material share favorable, but both are limited by adverse effects on the electrode quality. The adverse effects of fast drying are associated with the migration of binder. In this article, the slurry properties of water-based graphite slurries are manipulated using a synthetic, layered silicate as additive. The influence of the polymer-particle composite network on the viscosity, adhesion strength, and cell performance is investigated. By addition of a small amount of additive (0.5 wt% of the dry electrode), the binder migration is mitigated up to a drying rate of 6 g m−2 s−1 for graphite anodes with ≈4.2 mAh cm−2 (corresponding with 30 s drying time) leading to a possible increase of eight times the process speed compared to drying with 0.75 g m−2 s−1 if adverse effects on the tortuosity of the electrodes can be solved. In this work, a combination of additive usage is pointed out with a multilayer approach and first insights are provided in how the binder migration may be mitigated to gain structurally optimized fast-dried electrodes without losses in electrode quality.