Encapsulating Silicon Nanoparticles Within a 3D Interconnected Ultra‐Conductive Sodium Alginate@Ti ₃ C ₂ T _x Network for Robust and High‐Capacity Lithium‐Ion Batteries

ABSTRACT 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 Ti ₃ C ₂ T _x , thereby enhancing the mechanical stability and charge transfer efficiency within silicon anodes. The SA@Ti ₃ C ₂ T _x 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.