Gradient Multi‐Barrier Architecture Enabling High‐Performance Silicon‐Carbon Anodes

ABSTRACT Silicon (Si) as an ideal lithium‐ion battery anode is severely limited in industrial applications due to its inherent low electrical conductivity and electrode/electrolyte interface instability caused by volume expansion. Although alloying has emerged as a promising strategy to address the inherent drawbacks of Si anodes, achieving uniform dispersion of the alloy and enhancing alloying efficiency remain significant challenges. Here, we synergistically exploit metal–organic frameworks and graphene to construct a novel alloyed composite material (S/CS@CG) with a gradient multi‐barrier protective architecture. Uniform metal sites achieve atomic‐level anchoring of cobalt within the Si matrix, while a gradient multifunctional carbon layer is further engineered to stabilize electrode/electrolyte interface reactions. This gradient design endows S/CS@CG with superior rate capability and cycling stability. More importantly, full cells pairing S/CS@CG/graphite composite anodes with LiFePO 4 (LFP) or LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathodes deliver impressive energy densities of 510.5 and 434.1 Wh kg −1 , respectively. Even after 200 cycles at 1 C, the S/CS@CG/Graphite//LFP full cell maintained a capacity retention rate of 93.8%. This study demonstrates the effectiveness of gradient functional coatings in synergistically optimizing diffusion kinetics and interface stability, while also providing a unique design concept and research strategy for homogenized alloys.