Ferroelectric‐Conductive Cathode‐Collector Contacts Enable Deep and Reversible Zn Storage

ABSTRACT

Aqueous Zn‐ion batteries are promising for grid‐scale storage, yet cathode capacities are often limited by the sluggish kinetics and poor reversibility of deep Zn ²⁺ insertion. Although extensive efforts have focused on tuning cathode chemistries, the cathode–current collector contact remains largely overlooked as a kinetic bottleneck where ionic and electronic transport become mismatched. Here, we introduce a ferroelectric‐conductive BaTiO ₃ @carbon nanotube (BTO@CNT) bridging interlayer between VO ₂ cathodes and Ti collectors, constructed via catalytic pyrolysis to integrate BTO nanoparticles within a percolating CNT network. The CNT framework preserves durable ohmic contact and efficient electronic conduction during cycling, while ferroelectric polarization from BTO alleviates the large voltage hysteresis associated with deep Zn ²⁺ insertion in VO ₂ cathodes. Together, these effects improve the synchronization between Zn ²⁺ insertion and electron delivery at the electrode level, suppress kinetic trapping, and enable deeper and more reversible charge storage. As a result, BTO@CNT‐modified 3.28 Ah Zn||VO ₂ pouch cells cycle stably for over 130 cycles, whereas control cells show pronounced capacity fading from the fifth cycle. More broadly, this ferroelectric‐conductive bridging strategy establishes functional interlayers as a practical route to regulate active‐material–current‐collector interfaces in aqueous batteries.