A Microscopically Heterogeneous Colloid Electrolyte for Extremely Fast‐Charging and Long‐Calendar‐Life Silicon‐Based Lithium‐Ion Batteries

Abstract Fast‐charging capability and calendar life are critical metrics in rechargeable batteries, especially in silicon‐based batteries that are susceptible to sluggish Li + desolvation kinetics and HF‐induced corrosion. No existing electrolyte simultaneously tackles both these pivotal challenges. Here we report a microscopically heterogeneous covalent organic nanosheet (CON) colloid electrolyte for extremely fast‐charging and long‐calendar‐life Si‐based lithium‐ion batteries. Theoretical calculations and operando Raman spectroscopy reveal the fundamental mechanism of the multiscale noncovalent interaction, which involves the mesoscopic CON attenuating the microscopic Li + ‐solvent coordination, thereby expediting the Li + desolvation kinetics. This electrolyte design enables extremely fast‐charging capabilities of the full cell, both at 8 C (83.1 % state of charge) and 10 C (81.3 % state of charge). Remarkably, the colloid electrolyte demonstrates record‐breaking cycling performance at 10 C (capacity retention of 92.39 % after 400 cycles). Moreover, benefiting from the robust adsorption capability of mesoporous CON towards HF and water, a notable improvement is observed in the calendar life of the full cell. This study highlights the role of microscopically heterogeneous colloid electrolytes in enhancing the fast‐charging capability and calendar life of Si‐based Li‐ion batteries. Our work offers fresh perspectives on electrolyte design with multiscale interactions, providing insightful guidance for the development of alkali‐ion/metal batteries operating under harsh environments.