Mechanically Interlocked Polymer Electrolyte with Built-In Fast Molecular Shuttles for All-Solid-State Lithium Batteries

The mobility of molecular shuttles inside a mechanically interlocked polymer (MIP) can improve the ionic conductivity and electron transport capacity of a solid polymer electrolyte (SPE) and maintain a mechanically tough structure. The polyrotaxane-based MIP electrolyte with a necklace-like molecular structure exhibits high ionic conductivity (σ = 5.93 × 10⁻³ S cm⁻¹ at 25 °C and 1.44 × 10⁻² S cm⁻¹ at 60 °C), a high Li⁺ ion transference number (t₊ = 0.71), and high electrochemical oxidation stability (≈4.7 V vs Li⁺/Li). When SPEs are used in Li-based batteries, a high Coulombic efficiency (≥98.5%), an excellent rate capability, and fast charging (≥2C) can be achieved using a “built-in molecular shuttle” design.