Encapsulating Silicon Nanoparticles Within a 3D Interconnected Ultra-Conductive Sodium Alginate@Ti3C2Tx Network for Robust and High-Capacity Lithium-Ion Batteries.

High-capacity silicon-based electrodes experience significant volumetric expansion and contraction during cycling, which induces critical mechanical stress, leading to the fracture of conductive networks and instability of the solid-electrolyte interphase (SEI). To address these challenges, we develop a 3D resilient and conductive binding network through the cross-linking of sodium alginate (SA) with MXene Ti3C2Tx, thereby enhancing the mechanical stability and charge transfer efficiency within silicon anodes. The SA@Ti3C2Tx binding network effectively reduces the growth rate of electrode thickness from 100.6% to 46.6%, mitigating electrolyte decomposition and excessive SEI growth during cycling, and contributing to the formation of a stable LiF-rich SEI layer on silicon surfaces. Enhanced mechanical strength and electron conduction provided by the 3D interconnected conductive network facilitate a high reversible capacity of 1247.01 mAh g-1 after 300 cycles and excellent rate capability of 778.12 mAh g-1 at a current density of 2 A g-1, even with a silicon content as high 80% by weight. By simultaneously reinforcing the mechanical stability and electron transport pathways, this work paves the way for innovative design of high-capacity negative electrodes.