A Novel Organosilicon-Type Binder for Licoo2 Cathode in Li-Ion Batteries

Abstract

The conventional binder used in LIBs, polyvinylidene fluoride (PVDF), possesses low mechanical ductility and weak affinity to electrode materials and therefore cannot prevent pulverization of the cathode materials or undesirable battery swelling after prolonged cycling. Herein, we introduce a novel organosilicon-type binder (S-binder), composed of siloxane (Si–O–Si), silanol (Si–O–H), and cyclohexene oxide (C6H10O) groups. It is demonstrated that S-binder exhibits the enhanced adhesion to the cathode, high elasticity, and great flexibility compared with PVDF, resulting in exceptionally improved electrochemical performances of LiCoO2. In terms of cyclability, S-binder-applied LiCoO2 electrode with high mass loading of the active material (~8 mg cm−2) exhibits outstanding capacity retention of ~92.0% compared with the initial capacity after 100 cycles. From industrial perspective, simulation of the slot-die coating on S-binder- and PVDF-applied slurries indicates the high competitiveness of S-binder compared with PVDF for the mass-production of LiCoO2 electrode for LIBs.

Keywords: High structural stability, Silicon-organic-based binder, Li-ion Batteries, Slot-die coating, First-principles calculation