Cross-Linked Poly(acrylic acid) with Polycarbodiimide as Advanced Binder for Si/Graphite Composite Negative Electrodes in Li-Ion Batteries

Abstract

Cross-linked poly(acrylic acid) (PAA) with polycarbodiimide (PCD) is utilized as a binder for the Si/graphite composite electrode. Cross-linkage of PAA can be modulated by the addition of the PCD as a cross-linker into the slurry. Compared to PAA binder, initial reversible capacity of Si/graphite composite electrodes is increased with suppressed electrolyte decomposition by the use of cross-linked PAA. The electrode adhesion strength onto current collector is increased by the cross-linking of PAA with PCD. The Si-composite electrode with optimal amount of 1 wt% PCD cross-linker delivers more than 1,000 mAh g⁻¹ of reversible capacity with improved capacity retention.