Wet-processed high-areal-capacity electrodes via transformative spandex-poly(acrylic acid) binder toward 450 Wh kg^-1...

Driven by the increasing interest in lithium-ion batteries with high energy density, the design of high-mass-loading electrodes with Ni-rich positive materials has recently been considered one of the most promising strategies to achieve this goal. However, the conventional binder, poly(vinylidene fluoride), cannot ensure structural integrity and uniform charge transfer in high-mass-loading electrodes. Herein, we propose a dual-acting hybrid polymer as an advanced wet-processable binder, comprising a crosslinked network of spandex and polyacrylic acid. Spandex imparts high elasticity and strong affinity with Ni-rich positive electrode, while poly(acrylic acid) forms lithium polyacrylate on the electrode surface to enhance interfacial Li⁺ transport. The distinct roles of each polymer ensure mechanical robustness, enhance Li⁺ transport, and suppress binder migration during the drying process, thereby alleviating chronic issues in high-mass-loading electrodes. Notably, proposed hybrid polymer binder enables the fabrication of high-mass-loading electrodes (70 mg cm^-2) with stable cyclability, despite a low binder content of 2 wt%. Moreover, pouch cell employing high-loading positive electrode based on the hybrid polymer binder exhibited improved cycling stability over its conventional poly(vinylidene fluoride)-based counterparts, ultimately highlighting its industrial applicability. This study provides practical insights into rational design of binders and highlights their potential to enable wet-processable fabrication of high-mass-loading electrodes.