A Facile Candle-Soot Nanoparticle Decoration Enables Dendrite-Free Zn Anodes for Long-Cycling Aqueous Batteries

The practical application of aqueous Zn-metal batteries (ZMBs) is largely hampered by awful parasitic reactions and notorious dendrite growth occurring on Zn anodes. Herein, we directly form a uniform candle-soot (CS) carbon nanoparticle layer on the Zn anode (denoted as CS-Zn) using a facile flame vapor deposition method. The CS layer tightly covers the Zn surface and thus mitigates electrolyte corrosion products. In addition, it balances the electric field and induces fast and even Zn nucleation, promoting interfacial reaction kinetics and suppressing dendrite growth. Benefiting from this synergy effect, CS-Zn allows a low voltage overpotential of 28 mV and a good cyclability (256 h) under an aggressive 5 mA cm–2/5 mAh cm–2 cycling in symmetric cells. Furthermore, the CS-Zn||NaV3O8·1.5H2O (NVO) full cell delivers a high initial capacity of 123.9 mAh g–1 and a capacity retention of 77.2% after over 1000 cycles at 2 A g–1, significantly surpassing those of the Zn||NVO cells (93.9 mAh g–1, 50.3%). The present work offers a simple and cost-efficient strategy to stabilize metallic Zn anodes in progressive aqueous batteries.