Gradient H-Bonding Binder Enables Stable High-Areal-Capacity Si-Based Anodes in Pouch Cells

Abstract

Alleviating large stress is critical for high-energy batteries with large volume change upon cycling, yet this still presents a challenge. Here, a gradient hydrogen-bonding binder is reported for high-capacity silicon-based anodes that are highly desirable for the next-generation lithium-ion batteries. The well-defined gradient hydrogen bonds, with a successive bond energy of -2.88- -10.04 kcal mol^-1 , can effectively release the large stress of silicon via the sequential bonding cleavage. This can avoid recurrently abrupt structure fracture of traditional binder due to lack of gradient energy dissipation. Certainly, this regulated binder endows stable high-areal-capacity silicon-based electrodes >4 mAh cm^-2 . Beyond proof of concept, this work demonstrates a 2 Ah silicon-based pouch cell with an impressive capacity retention of 80.2% after 700 cycles (0.028% decay/cycle) based on this gradient hydrogen-bonding binder, making it more promising for practical application.

Keywords: gradient hydrogen bonding; high-energy-dissipation binders; lithium-ion batteries; pouch cells; silicon-based anodes.