An Ultrastable Integrated Anode with ∼95 wt.% SiO_x via In Situ Electrode-Scale Conformal Coating

SiO_x-based anodes, considered the most promising candidate for high-energy density batteries, have long been bothered by mechanical integrity issues. Research efforts focus on particle modifications, often overlooking the enhancement of interparticle connections, which can reduce the active material content within the electrode. Herein, an integrated electrode with strong covalent bonding at the electrode scale is designed, achieving excellent mechanical stability with ∼95 wt.% SiO_x. Thermal treatment triggers in situ copolymerization of the organic binder to form a three-dimensional continuous conductive mechanical matrix throughout the electrode. The synergistic effects of surficial electron dispersion and stress mitigation combine to improve structural integrity and restrain volume expansion. As a result, the integrated anode delivers a promising capacity of 1277 mAh g^-1 and a capacity retention of 81.82% after 250 cycles at 1580 mA g^-1. The assembled full-cell realizes a high initial Coulombic efficiency of 91.33% and a superior energy density of 400.05 Wh kg^-1. The crucial formation mechanism of two-layered SEI on the integrated electrode is also thoroughly investigated. This work provides a facile procedure that is compatible with commercial production to develop a microsized SiO_x-based anode with ultrahigh active material proportion and emphasizes modification at the electrode scale.