High-Areal-Loading Zinc-Ion Batteries with Long-Term Cycling at Practical Current Densities with Scalable Electrode Design.

Aqueous zinc-ion batteries (ZIBs) offer a safe and cost-effective solution for stationary energy storage, but achieving long-term cycling at high areal loadings and low C-rates remains challenging. Here, we present a polyaniline-based ZIB with a unique 3D interconnected sponge-like carbon nanotube (CNT) host that provides high porosity, mechanical resilience, and robust conductivity. This architecture supports active material loading up to 6 mg cm^-2, enabling stable cycling at practical current densities. With a dimethyl sulfoxide electrolyte additive, the cell retains 70% capacity over ∼6,000 cycles at 0.68C, highlighting its outstanding long-term stability at low rates. It also maintains ∼9,000 cycles at 6.8C, demonstrating high-rate capability. To demonstrate scalability, we implemented a solvent-free dry electrode process using CNT chunks and polytetrafluoroethylene binder, achieving a high areal loading of 7.9 mg cm^-2 and delivering 140 mAh g^-1 at 0.5 C. These results represent a significant step toward durable, high-loading, and scalable ZIBs for grid-level energy storage applications.