Resilient ion/electron dual conductive network with covalent/hydrogen bond cross-linking enables stable and high-energy-density Si–C anodes for lithium-ion batteries

Abstract

The application of Si-based anodes is mainly impeded by their intrinsic volumetric stress. Recently proposed elastic binders have been demonstrated as an efficient approach to alleviate this large stress, but the excessive dosage of binders leads to inadequate energy density. Herein, a 3D resilient ion/electron dual conductive network (LPCC) composed of carboxylic carbon nanotubes (c-CNTs) interwoven with carboxymethyl chitosan (c-CS) and lithiated poly(acrylic acid) (LiPAA) was developed. The formed covalent and hydrogen bonds can endure and dissipate volumetric stress, thereby maintaining electrode integrity. Additionally, the LPCC network intimately wraps Si–C particles and provides a continuous ion/electron dual conductive skeleton. Therefore, this novel 3D network enables Si–C anodes to deliver superior electrochemical performance even at a high Si–C content of 96 wt%. Moreover, an NCM811‖Si–C/LPCC full-cell (>3.1 mA h cm⁻²) achieves unprecedented high gravimetric and volumetric energy densities of 510 W h kg⁻¹ and 1173 W h L⁻¹, respectively. This study provides novel insights for developing efficient Si-based binders for next-generation high-energy-density systems.