Direct Growth of Leopard-Patterned Graphene on Zinc Anodes via Sonochemistry for High-Performance Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries encounter issues with the formation of Zn dendrites and parasitic reactions at Zn anodes. To address these issues, coating Zn anodes with two-dimensional (2D) nanocarbon materials, such as graphene, has proven effective in ensuring uniform current distribution and facilitating charge transfer. While direct growth of 2D nanocarbon on Zn substrates offers significant advantages, it remains challenging due to Zn's low melting point (420°C). In this study, as a first proof-of-concept, a unique sonochemical route was developed to directly grow crystalline-amorphous mixed 2D nanocarbon films, named “Leopard-patterned graphene,” on Zn substrates. This unique structure provides uniform nucleation sites while maintaining high Zn2+ ion permeability, mitigating dendrite formation. In Zn symmetric coin cell tests, the Zn electrodes coated with Leopard-patterned graphene maintained stable cycling for over 2000 h at a constant current density of 3 mA cm−2. This study introduces an innovative approach for bottom-up synthesis of 2D nanocarbon on Zn substrates under ambient conditions and demonstrates its potential to address critical challenges in Zn-ion battery performance. The findings provide insights into advanced electrode design strategies for next-generation energy storage devices.