Entropy‐Driven Ultrafast Ion Conduction Via Confining Organic Plastic Crystals in Ordered Nanochannels of Covalent Organic Frameworks

Abstract Low conductivity over a wide temperature region due to ultra‐slow ion migration dynamics is a key issue in the field of solid‐state electrolytes (SSE), which needs to be solved and improved. Covalent organic frameworks (COFs), a rapidly growing class of porous crystalline materials, emerge as a new research hotspot in the field of SSEs. This is due to their homogeneously dispersed sites and well‐defined pathways for ion diffusion, demonstrating great advantages over conventional non‐porous solids. Herein, a composite solid electrolyte by confining organic ionic plastic crystal (OIPC) in the 1D ordered nanochannels of COFs as the host matrix for solid‐state lithium‐ion conduction, is reported. Due to the loss of coupling between PBu 4 + cations and TFSI − anions, the cation–anion interaction is weakened; and thus, the lithium‐ion transportation is facilitated. As a result, the COF‐confining OIPC SSEs show ultra‐high lithium‐ion conductivity of 0.048 S cm −1 at 30 °C and 0.021 S cm −1 at the extremely low temperature of −30 °C. The dynamic origin of this fast ion conduction is characterized by differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopy (XPS), and variable temperature solid‐state nuclear magnetic resonance (NMR) spectroscopy.