Three‐Dimensional Through‐Localized Amorphization Engineering of Crystalline/Amorphous Heterophase Ammonium Vanadate Nanobelts for Advanced Aqueous Zinc‐Ion Batteries

Abstract A 3D through‐localized amorphization strategy is proposed to concurrently address the sluggish Zn ²⁺ diffusion kinetics and structural instability for aqueous zinc‐ion batteries (AZIBs) cathodes by constructing crystalline/amorphous heterophase ammonium vanadate ( c/a ‐NVO) nanobelts. The crystalline networks enhance electron transport efficiency and stabilize the amorphous active domains via their rigid structure, thereby reducing the dissolution of unsaturated vanadium by over 51.67%. The amorphous phase introduces 45.4% oxygen defects and isotropic Zn ²⁺ diffusion channels, effectively shortening diffusion paths and reducing structural strain during Zn ²⁺ insertion/de‐insertion. Furthermore, theoretical calculation indicates that the heterointerface‐induced built‐in electric field redistributes charge density, thus accelerating charge transfer kinetics and lowering Zn ²⁺ diffusion barriers. As a proof‐of‐concept application, the c/a ‐NVO cathode delivers a specific capacity of 304 mAh g ⁻¹ at 0.5 A g ⁻¹ and retains 166.39 mAh g ⁻¹ after 10,000 cycles at 15 A g ⁻¹ , achieving 89.22% capacity retention even after 16,000 cycles. Notably, this c/a heterophase design preserves 77.13% of its initial specific capacity in a functional pouch cell after 1,000 cycles. The findings provide a c/a heterophase engineering strategy for designing advanced cathode materials for next‐generation AZIBs.