Elastic Framework Driven Mg ²⁺ Autocapture and Autocatalysis: Mechanistic Origin of Fast Hydrogen Release in 2LiBH ₄ –MgH ₂

The protracted incubation time has long been the Achilles' heel of the promising 2LiBH 4 –MgH 2 hydrogen storage system. Instead of the usual route‐creating heterogeneous nucleation sites to hasten MgB 2 formation, we shortened both de‐ and re‐hydrogenation incubation periods by steering the Mg transformation itself. Herein, this paper engineered a Prussian blue analog whose surface charge landscape traps Mg 2+ and the released electrons in a non‐stoichiometric lattice, keeping them instantly available for MgB 2 nucleation. Theory and experiment show that CoFe–PBA stores both ions and electrons. Under the same experimental temperature, the optimized LiBH 4 –MgH 2 hydrogen storage system demonstrates remarkable performance improvements: Its incubation period is significantly reduced to just one seventh that of the original hydrogen storage material, achieving a leap forward in reaction kinetics efficiency. The above concept provides a versatile tool for any catalytic system constrained by nucleation delays and opens new avenues for energy‐related research.