Dual‐Armor Architecture‐Mediated Microstructural Engineering of Germanium Anode for Advanced Liquid‐ and Solid‐State Batteries

Germanium (Ge) is an attractive anode material for advanced lithium‐ion batteries (LIBs) due to its high theoretical capacity, excellent Li + diffusivity, and high electronic conductivity. However, its substantial volume variation and unstable solid electrolyte interphase (SEI) during cycling lead to rapid capacity decay. Here, a p‐Ge/SiO 2 /NC‐2 composite with a dual‐armor architecture is developed through a rational pore‐filling and interface engineering strategy. This unique structure features a porous Ge skeleton with embedded SiO 2 microspheres and an outer N‐doped carbon layer, forming a stable inner support and outer confinement system. The mechanical integrity is enhanced by the porous structure and the rigid SiO 2 particles, which collectively inhibit pore collapse and mitigate volume expansion. Meanwhile, the N‐doped carbon layer not only facilitates rapid charge transfer but also promotes the formation of a stable SEI enriched with LiF and Li 3 N in liquid electrolyte systems. Finite element simulation further verifies that this synergistic dual‐armor design enables low stress strain and high structural stability during cycling. As a result, the composite anode demonstrates exceptional lithium storage performance, achieving a high capacity retention of 94.4% after 250 cycles at 0.5 C in the LFP||p‐Ge/SiO 2 /NC‐2 full cells. Notably, the p‐Ge/SiO 2 /NC‐2||LPSC||Li all‐solid‐state lithium‐ion batteries (ASSLIBs) with a sulfide solid electrolyte maintain stable cycling, delivering a specific capacity of 449 mAh g −1 at 0.5 A g −1 . This work highlights the crucial role of rational structural design in advancing Ge‐based anodes for high‐performance energy storage systems.