Harnessing interlayer-active organic polymer anchoring in ammonium vanadate realize high-capacity and durable zinc-ion storage

Ammonium vanadate (NH₄V₄O₁₀, NVO) has attracted attention as a promising AZIB cathode due to its ability to undergo multi-electron redox reactions, enabling large capacity, and its NH₄⁺-stabilized layered structure, which provides excellent structural stability. However, its application is limited by sluggish Zn²⁺ kinetics and structural degradation caused by irreversible de-ammoniation. Herein A dual-active-site composite (NVO-PSBQ) was synthesized hydrothermally in a single step, wherein poly(2,3-disulfide-1,4-benzoquinone) (PSBQ) was intercalated in situ into NVO interlayers. PSBQ intercalation expands the interlayer spacing to 10.2 Å, optimizes charge distribution, and reduces Zn²⁺ diffusion barriers. The reversible C=O/C-O redox transformation in PSBQ enables additional pseudocapacitive Zn²⁺ storage. Furthermore, strong polar carbonyl groups form electrostatic anchoring interactions with interlayer NH₄⁺, suppressing de-ammoniation and preserving structural integrity. Benefiting from the cooperative effects between the inorganic host and organic intercalant, the NVO-PSBQ hybrid delivers excellent electrochemical properties, including a reversible capacity of 410 mAh g^-1 at 1 A g^-1, sustained performance of 250 mAh g^-1 even under 5 A g^-1, and long-term durability with 82.3 % capacity retention over 1500 cycles. This study highlights inorganic-organic co-intercalation as an effective strategy for next-generation AZIB cathode design.