Regulating electrostatic phenomena by cationic polymer binder for scalable high-areal-capacity Li battery electrodes.

Kim, Jung-Hui; Lee, Kyung Min; Kim, Ji Won; Kweon, Seong Hyeon; Moon, Hyun-Seok; Yim, Taeeun; Kwak, Sang Kyu; Lee, Sang-Young · Nat Commun · 2023

basic_science · Level V

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Abstract

Despite the enormous interest in high-areal-capacity Li battery electrodes, their structural instability and nonuniform charge transfer have plagued practical application. Herein, we present a cationic semi-interpenetrating polymer network (c-IPN) binder strategy, with a focus on the regulation of electrostatic phenomena in electrodes. Compared to conventional neutral linear binders, the c-IPN suppresses solvent-drying-induced crack evolution of electrodes and improves the dispersion state of electrode components owing to its surface charge-driven electrostatic repulsion and mechanical toughness. The c-IPN immobilizes anions of liquid electrolytes inside the electrodes via electrostatic attraction, thereby facilitating Li<sup>+</sup> conduction and forming stable cathode-electrolyte interphases. Consequently, the c-IPN enables high-areal-capacity (up to 20 mAh cm<sup>-2</sup>) cathodes with decent cyclability (capacity retention after 100 cycles = 82%) using commercial slurry-cast electrode fabrication, while fully utilizing the theoretical specific capacity of LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub>. Further, coupling of the c-IPN cathodes with Li-metal anodes yields double-stacked pouch-type cells with high energy content at 25 °C (376 Wh kg<sub>cell</sub><sup>-1</sup>/1043 Wh L<sub>cell</sub><sup>-1</sup>, estimated including packaging substances), demonstrating practical viability of the c-IPN binder for scalable high-areal-capacity electrodes.