Laser Printing of Silicon-Containing Anodes with Polyacrylic Acid

To enhance the performance of state-of-the-art lithium-ion batteries, high-capacity silicon is increasingly introduced as active material for anodes. Furthermore, advanced batteries with new electrode architectures—so-called 3D architectures—can provide significantly enhanced electrochemical performance compared to state-of-the-art batteries. To facilitate and speed up the architectural development, the laser-induced forward transfer (LIFT) process was applied as a digital additive manufacturing method. As polyvinylidene fluoride (PVDF), the binder commonly used in the LIFT process, is not a suitable binder for silicon-containing electrodes due to its weak binding forces, polyacrylic acid (PAA) was introduced as a binder for use in printable electrode pastes. Since water as a solvent in such pastes evaporates quickly and the corresponding printing time would be too short, glycerol was added to the solvent mixture in different amounts. The silicon in the printed electrodes reaches a specific capacity of more than 3000 mAh·g–1 for most of the printed anodes. To further improve the electrochemical performance of the printed electrodes, as well as the rheology of the slurries, two different conductive additives with different particle sizes were used.