Constructing Ionic Transport Network via Supramolecular Composite Binder in Cathode for All‐Solid‐State Lithium Batteries

Abstract

Binders play a pivotal role in maintaining the structural integrity and stability of electrodes. However, conventional polyvinylidene fluoride binder with low ionic conductivity could not meet the ionic transport requirements of the cathode in all‐solid‐state lithium batteries (ASSLBs). Herein, a composite binder (PPCL) derived from the cross‐linking of linear molecules and mechanically interlocked molecules with typical supramolecular channel structure is designed. The supramolecular channel structure is afforded through β‐cyclodextrin rings crosslinked polyethylene oxide chains by hydrogen bond interaction. Through the coordination of supramolecular with linear polymer, the PPCL binder provides multiple and synergistic Li+ transport channels to achieve stable Li+ transport inside the cathode. As a result, the obtained PPCL binder not only maintains exceptional adhesive strength which could achieve robust electrode structural stability but also helps to construct multiple and highly efficient Li+ transport channels. Therefore, with PPCL binder, the LiFePO4‐based ASSLBs show an excellent rate capability and long cyclic stability over 1000 cycles at 1 C. Notably, a pouch ASSLB shows excellent cycling stability over 250 cycles at 0.2 C. This work provides guidance on designing high‐loading cathodes for advanced ASSLBs.