Harnessing N─H···O═V Bonding Toward Stable Vanadium Cathodes in Ah-Level Zn-Ion Batteries.

Abstract

The vanadium-based batteries deliver great potential in Ah-level energy storage systems, ascribing to their high specific capacity. Nevertheless, the metal-oxygen bonds are unstable in aqueous electrolytes, resulting in structural degradation and capacity attenuation. Here, inspired by the robust N─H···O═C bonding that stabilizes protein structures, we propose a bioinspired polymer-integrated electrolyte based on poly(N-acryloyl glycinamide) (PNAGA). The amide-rich N-H groups in PNAGA can anchor onto vanadium oxide units (O═V) via strong protein-like intermolecular N─H···O═V interactions, which effectively stabilize the cathode framework by suppressing vanadium dissolution and preserving structural integrity during Zn²⁺ intercalation and deintercalation. In addition, the PNAGA can establish an electron-enriched environment on the vanadium cathode surface via N─H···O═V hydrogen bonding to accelerate redox kinetics for high rate capability and cycling stability. Consequently, the Zn/Zn_0.25V₂O₅ full battery delivers a high specific capacity of 286.2 mA h g^-1 with 97% capacity retention over 1000 cycles at 2 A g^-1. Meanwhile, the PNAGA-enabled pouch cell can achieve 1.35 Ah at 0.15 A g^-1, demonstrating a universal molecular design strategy for high-performance aqueous vanadium-based batteries.