Stable silicon anodes realized by multifunctional dynamic cross-linking structure with self-healing chemistry and enhanced ionic conductivity for lithium-ion batteries

Abstract

Silicon anodes have attracted enormous attention with the merits of outstanding theoretical capacity for high-energy-density lithium-ion batteries. However, the drastic volume variation will destroy the structural integrity of the electrode system during the alloying/dealloying process. Herein, based on the supramolecular self-assembly, a multifunctional dynamic cross-linking strategy with self-healing chemistry and enhanced ionic conductivity for silicon electrode network structure is rationally designed by amino-functionalized silicon (Si-NH2) and dopamine-modified poly(acrylic acid) (PAA-DA). Dynamic reversible hydrogen bonds and ionic bonds are formed by random cross-linking of the primitives carried by the material, which endow the electrode with rapid self-healing ability and strong adhesion, and provide a continuous internal pathway for the electrode system. Moreover, the presence of polar groups can beneficially heighten the transport kinetics of lithium ions. The prepared Si-NH2@PAA-DA electrode displays excellent high-rate capability with a reversible capacity of 2671.6 mAh g−1 at 1 C (1 C = 4000 mA g−1) and superior cycle stability (2160.1 mAh g−1 after 100 cycles at 400 mA g−1). Therefore, this design idea with dynamic reversible and multi-crosslink network structure provides in-depth insights for the advancement of the next-generation high-energy-density batteries.