Solvent‐Free Manufacturing of Electrodes for Lithium‐Ion Batteries via Electrostatic Coating

Abstract

This work demonstrates the feasibility of a novel solvent‐free anode production for lithium‐ion batteries. It combines a modified dry‐mixing procedure with an innovative electrostatic coating process. The mixing is divided into two steps. At first, carbon black and binder are deagglomerated and recombined to a matrix structure by intensive mixing. In a second less intensive step, this matrix is blended with graphite. The powder mixture is fluidized and then transferred to the current collector by inducing a high voltage. After a subsequent hot pressing step, the powder coating is permanently fixed on the current collector. This procedure is presented with three different fluorinated binders. Furthermore, effects of different mixing intensities on the powder and electrode properties are examined. The electrodes are investigated in the three‐electrode T‐cell setup versus lithium metal to examine their C‐rates and cycle stabilities. The produced anodes offer comparable electrochemical performance to conventional wet‐coated ones on electrode and cell levels. Overall, this new process is a suitable alternative to the conventional electrode production techniques.

Current and future lithium-ion battery manufacturing

“…These improvements can be explained as the thermal treatment increased the elastic deformability (decrease of the shear modulus) of the thermoplastic binder, such as PVDF (Billot et al, 2019). Similar superior mechanical properties also occurred in the solvent-free coated electrodes, which were hot calendered or hot pressed after dry deposition (Ludwig et al, 2016;Schä licke et al, 2019).…”

“…Reproduced from Schälicke et al. ( Schälicke et al., 2019 ). (C) Innovative formation technologies: (I) Fast formation protocol by limiting the voltage window.…”

“…Schälicke et al. combined a fluidized bed and electrostatic system to achieve a solvent-free coating method for the graphite anode and compared the effect of different binders (tetrafluoroethylene, hexafluoropropylene vinylidene fluoride [THV], and fluorinated ethylene propylene [FEP]) ( Figure 3 BIII) ( Schälicke et al., 2019 ).…”

Opportunities for the State-of-the-Art Production of LIB Electrodes—A Review

“…The next generation processing of electrodes should reduce the costs and eliminate the toxicity to meet future battery production demands. Some of the most promising alternatives for the current wet slurry processing mentioned in literature are shown in Table 8, including solvent reduction, alternative solvent recovery methods, water-based processing [90,176,177], and dry electrode processing [73,[178][179][180][181][182][183][184][185]. Among future generations battery technologies, both new electrode chemistries and solid-state electrolyte (SSE) concepts have emerged.…”

Sustainable Solvent‐Free Production and Resulting Performance of Polymer Electrolyte‐Based All‐Solid‐State Battery Electrodes

“…It is already a current topic of LIB process research to reduce the solvent content during production or to even realize a solventfree processing. [36][37][38] In LIB production, the porosity of the electrode originates from the evaporation of the solvent. [39,40] However, reaching sufficient porosity via solvent-free production remains an issue.…”