Stabilizing the Bulk-phase and Solid Electrolyte Interphase of Silicon Microparticle Anode by Constructing Gradient-Hierarchically Ordered Conductive Networks

The poor bulk-phase and interphase stability, attributable to adverse internal stress, impede the cycling performance of silicon microparticles (μSi) anodes and its commercial application for high-energy-density lithium-ion batteries. In this work, we propose a groundbreaking gradient-hierarchically ordered conductive (GHOC) network structure, ingeniously engineered to enhance the stability of both bulk-phase and the solid electrolyte interphase (SEI) configurations of μSi. Within the GHOC network architecture, two-dimensional transition metal carbides (Ti3C2Tx) acts as a conductive "brick", establishing a highly conductive inner layer on μSi, while the porous outer layer, composed of one-dimensional Tempo-oxidized cellulose nanofibers (TCNF) and polyacrylic acid (PAA) macromolecule, functions akin to structural "rebar" and "concrete", effectively preserves the tightly interconnected conductive framework though multiple bonding mechanisms, including covalent and hydrogen bonds. Additionally, Ti3C2Tx enhances the development of a LiF-enriched SEI. Consequently, the μSi-MTCNF-PAA anode presents a high discharge capacity of 1413.7 mAh g-1 even after 500 cycles at 1.0 C. Moreover, a full cell, integrating LiNi0.8Mn0.1Co0.1O2 with μSi-MTCNF-PAA, exhibits a capacity retention rate of 92.0% following 50 cycles. This GHOC network structure could offer an efficacious pathway for stabilizing both the bulk-phase and interphase structure of anode materials with high volumetric strain. This article is protected by copyright. All rights reserved.