Synergistic interface engineering with carbon quantum dots for dendrite-free zinc anodes via regulated ion flux and...

Aqueous zinc-ion batteries (AZIBs) are promising eco-friendly energy storage systems, yet their practical application is hampered by issues such as uncontrolled zinc dendrite growth and parasitic side reactions. This study designs a flexible composite separator from cellulose acetate (CA) and carbon quantum dots (CQDs) to address these challenges. The CA-CQDs separator features a dense, homogeneous microstructure, abundant zincophilic functional groups, and high mechanical strength. Combined theoretical and experimental analyses demonstrate that this separator homogenizes the Zn²⁺ flux, accelerates ion transport kinetics, reduces the energy barrier for Zn²⁺ desolvation, and effectively suppresses dendrite formation. Consequently, a Zn||Zn symmetric cell with the CA-CQDs separator achieves exceptional cycling stability exceeding 2000 h at 1 mA cm^-2. When configured in Zn||V₂O₅ full cells and Zn||AC hybrid capacitors, the separator also enhances electrochemical kinetics and rate capability, confirming its practical utility. This work thus presents an effective separator design by integrating CQDs with low-cost biomaterials for AZIBs, providing a viable path toward high-performance, sustainable energy storage.