Electrophoretic deposition of LiFePO4 onto 3-D current collectors for high areal loading battery cathodes

Abstract

Three-dimensional (3-D) current collectors in lithium-ion batteries with high areal loading of cathode materials enables reduced packaging weight and cost compared to planar current collector materials. Here, we demonstrate the use of electrophoretic deposition (EPD) as a route to prepare thick cathode assembles in 3-D scaffolds using LiFePO4 with areal loadings measured from 2 mg/cm2 and up to 20 mg/cm2 in conductive carbon cloth materials. Our findings demonstrate the LiFePO4 cathodes with areal capacity up to ∼2.4 mAh/cm2 and minimal decay (<0.11%) per cycle. This emphasizes EPD as both a technique to overcome the limitations of conventional manufacturing approaches in scaling to 3-D collector architectures for improved cell-level energy density, but also a route to transition away from costly NMP processing toward cheaper, less toxic solvents, such as ethanol as is demonstrated in this study.