Homogeneous 3D Porous Conductive Electrodes for High-Energy Battery Fast Charging
Huayue Ai, Angela Cai, John Holoubek, Wenbo Zhang, Louisa C. Greenburg, Junyoung Lee, Sarah E. Holmes, Yoshiaki Suzuki, Hideaki Kuwajima, Ryuhei Matsumoto, Yusheng Ye, Yuri Nakayama, Yi Cui
Abstract
Fast charging in high-energy-density lithium-ion batteries (LIBs) is hindered by increased impedance and sluggish kinetics associated with thicker electrode coatings. In conventional batteries, the topmost active layer of the electrodes often experiences the highest electrical resistance due to its distance from the current collector. This, along with variations in planar electrical conductivity, creates localized charge flux imbalances that promote electrode reaction heterogeneity and, ultimately, lithium plating. Thicker electrodes also extend ionic pathways, further limiting the rate performance. Here, we develop three-dimensional porous electrodes─integrating current collectors and active materials─with homogeneous electrical conductivity and double the ionic transfer efficiency of traditional electrodes. These electrodes demonstrate thickness-independent electrical conductivity in both in-plane and out-of-plane directions. At an areal capacity of 3 mAh/cm 2, pouch cells with the designed electrodes exhibit excellent performance and stability, achieving 79.2%, 72.5%, and 62.3% state-of-charge (SOC) at 5C, 7C, and 10C, respectively. The straightforward fabrication process expands a potential route toward large-scale manufacturing.