Fast charging capability has become one of the key features of lithium-ion batteries (LIBs) to facilitate the rapid growth of the electric vehicle (EV) market. However, charging thick electrodes in conventional EV batteries at high current densities always leads to adverse battery performance and safety issues. To address these challenges, thick graphite electrodes with patterned porous architecture were developed through a facile printing process. With selected graphite and developed formula, an appropriate graphite ink was printed onto the copper foil through the screen printing with designed patterned pore channels. The porous structure including pore diameter and pore-to-pore distance was controlled via adjusting the designed patterns on the screens. The presence of porous structure was confirmed through microscopic images. The printed graphite electrodes exhibited superior electrochemical behaviors over traditional electrodes in terms of rate capability and cycle life. It is believed that the improved battery performance is associated with the improved Li-ion transport arising from the patterned porous structure in printed electrodes. Results from the electrochemical impedance spectroscopy (EIS) indicate that, compared with traditional electrodes without patterned pores, printed electrodes have significantly reduced tortuosity. The post-mortem analysis of cycled cells demonstrates that the printed electrodes have the capability to suppress the Li plating related to fast charging rates. Combining with the advantages of low cost and high throughput, the printed electrode with patterned pores, thus, has the potential of replacing conventional electrodes in commercial LIBs to realize the fast-charging application.

Keywords: Graphite, Printing, Fast charging, Li-Ion Batteries