Achieving dendrite-free anodes for aqueous zinc ion batteries using zinc anode coated with a rGO/biomass carbon composite for interfacial modification

Aqueous zinc ion batteries (AZIBs) have emerged as a promising member of the emerging energy storage battery family, attributed to their merits such as low cost, high safety, and environmental friendliness. However, their practical applications have been hampered by issues like side reactions and the growth of zinc dendrites. In this paper, we developed a method to prepare reduced graphene oxide (rGO)-attached biomass carbon composites (rGO/BC) for coating the zinc anode surface by using a simple hydrothermal method. Firstly, rGO was incorporated to offer more Zn-friendly sites, effectively suppressing the growth of zinc dendrites. Secondly, the flexible structure of rGO not only enhanced the reaction kinetics but also improved the structural stability of the rGO/BC composites. In addition, the synergistic effect of rGO and BC resulted in excellent electrical conductivity and electrolyte wettability of the zinc anode, thereby reducing the interfacial resistance. Thanks to these advantages, the AZIBs assembled with the rGO/BC@Zn anode exhibited excellent electrochemical performance. In composite experiments with different ratios, the symmetric cell assembled with rGO/BC-5, which demonstrated the best performance, had a low overpotential and achieved a cycle life of 2400 h at 1 mA cm-2 and 0.15 mA h cm-2. When this anode was paired with VO2, the rGO/BC-5@Zn//VO2 full cell showed outstanding cycling performance, maintaining a capacity retention of 83% after 2400 cycles at 5 A g-1. This work presents a novel interfacial approach for modifying zinc anodes with biomass-carbon composites, providing valuable insights for the development of high-performance AZIBs.