Remodeling Proton Insertion Chemistry via Interfacial Organic Layer for Fast-Charging and Robust Zn-VO₂ Batteries

Aqueous Zn-vanadium (Zn-V) batteries with high theoretical capacity are limited by sluggish Zn²⁺ diffusion kinetics, limited electronic conductivity, and structural instability, which impede the battery lifespan and rate capability. Herein, we fabricate a core-shell organic/inorganic heterostructure of modified VO₂ (denoted as P-VO₂) uniformly wrapped by poly(p-phenylenediamine, p-PDA) featuring interfacial V─N bonds for enhanced structural integrity and suppressed V dissolution. Theoretical calculations and in/ex situ characterizations proved the regulated proton insertion chemistry via ─C═N/─NH- chemistry in poly(p-PDA) for facilitated V⁵⁺/V⁴⁺/V³⁺ reaction kinetics and reversibility. As a result, the Zn//P-VO₂ battery showed a superb capacity of 383 mAh g^-1 at 0.2 A g^-1, superior rate performance (330 mAh g^-1 at 5 A g^-1), and extraordinary lifespan over 16 000 cycles. Moreover, a 143.6 Wh kg^-1 pouch cell shows ultrastability at -15°C after 200 cycles, underscoring its considerable potential. This work provides a new perspective on the study of organic-modified vanadium oxides for advanced Zn batteries.