Unlocking Interfacial Binder Chemistry for Efficient Li⁺ Desolvation in 3C-Rate Lithium Metal Pouch Cells

Lithium-ion transport dynamics at the cathode electrolyte interface play a crucial role in determining the performance of lithium batteries. However, most studies of ion-transport dynamics have focused on electrolyte-governed solvation structures and cathode electrolyte interphase (CEI) chemistry, while largely overlooking the complex interactions at the actual cathode surface. Herein, we unveil that interfacial binder chemistry plays a pivotal role in regulating Li⁺ desolvation dynamics and interfacial solvation configuration. Specifically, strongly polar functional groups (e.g., ─COOH and ─C≡N) engage in stronger interactions with Li⁺, facilitating rapid ion transport and reducing solvent molecule retention at the interface. This enhanced transport dynamics mitigates interphase degradation and preserves the cathode surface structure, thereby enabling stable cycling and high-rate performance of the LiNi_0.92Co_0.04Mn_0.04O₂ (Ni92) cathode. At the pouch-cell level, Ni92-PAN||Li cells deliver 505.1 Wh kg^-1 at 4.9 Ah and 506.2 Wh kg^-1 at 10.3 Ah, with stable cycling over 140 and 80 cycles, respectively. Moreover, a 5.8 Ah Ni92-PAN||Li pouch cell exhibits energy densities ranging from 523.8 to 405.7 Wh kg^-1 at discharge rates of 0.2 to 3 C. These findings identify interfacial binder chemistry as a key regulator of ion transport at the cathode electrolyte interface and underscore its importance in high-performance lithium batteries.