The application of a water-based hybrid polymer binder to a high-voltage and high-capacity Li-rich solid-solution cathode and its performance in Li-ion batteries

Uniform cathode films were prepared with a Li-rich solid-solution (Li[Li 0.2 Ni 0.18 Co 0.03 Mn 0.58 ]O 2 ) cathode material and a water-based hybrid polymer binder (TRD202A, JSR, Japan) composed of acrylic polymer and fluoropolymer, carboxymethyl cellulose, and conducting carbon additive. The films exhibited stable charge/discharge cycling performances (average discharge capacity: 260 mAh g −1 ) when cycled between 4.8 and 2.0 V for 80 cycles. After 80 cycles in the chemical environment of Li-ion cells, a cathode film prepared with the water-based hybrid polymer binder showed longer-term reliability as well as higher electrochemical resistance when compared with a cathode film using the conventional polyvinylidene difluoride binder. Additionally, even without electrochemical pretreatment, the Al 2 O 3 coating on the cathode surfaces improved the cycling stability by preventing the cathode surface from making direct contact with H 2 O. Graphical Abstract