Spidroin-Inspired Hierarchical Structure Binder Achieves Highly Integrated Silicon-Based Electrodes.

Abstract

As a promising component for next-generation high energy lithium-ion batteries, silicon-based electrode has attracted increasing attention by virtue of ultrahigh theoretical specific capacities. Nevertheless, fast capacity fade posed by tremendous silicon-based electrode volume changes during cycling remains a huge challenge before large-scale applications. Herein we develop an aqueous-oil binary solution based blend (AOB) binder characterized by a spidroin-like hierarchical structure for tolerating huge volume change of silicon-based electrodes. In AOB binder, the hydrophobic tetrazole groups-containing polymer (donate as PPB) and water-soluble amorphous poly(acrylic acid) mimicks the β-sheet and α-helix structure of spidroin, respectively. Benefitted by such biomimetic design, AOB binder enables both high tensile strength and elasticity, and strong electrode adhesion, therefore apparently stabilizing silicon-based electrode structure and rendering prolonged electrode cycle life. Such a strategy endows a 3.3 Ah soft package cells assembled with Si/C composite anode and NCM811 cathode with a discharge specific capacity of 2.92 Ah after 700 cycles. This work marks a milestone in developing state-of-the-art silicon-based electrodes towards high energy density lithium battery applications. This article is protected by copyright. All rights reserved.