One-Pot Electrochemical Exfoliation and Deposition of 3D Zincophilic Graphene Hosts for Dendrite-Free Zinc Metal Anodes

Owing to their safety, low cost, and high theoretical energy densities, aqueous Zn-ion batteries (ZIBs) are one of the most promising large-scale energy-storage devices. However, Zn anodes typically degrade the ZIB cycle stability and reversibility owing to dendrite formation and side reactions. Therefore, a three-dimensional (3D) N/O-codoped graphene (NOG) host is electrochemically synthesized in one pot for application to dendrite-free Zn anodes. The 3D NOG host exhibits a limited local current density, low nucleation overpotential, and uniform electric field distribution, which is more advantageous for reversible Zn plating/stripping. A symmetric cell fabricated using a Zn-deposited NOG (Zn@NOG) electrode exhibits excellent cycling stability for 300 h with apparently low voltage hysteresis and dendrite-free behavior, even at a high current density of 1 mA cm^-2. Consequently, the Zn@NOG//MnO₂ full battery exhibits considerably improved cycling stability and a high coulombic efficiency of more than 99% over 2500 cycles at 0.6 A g^-1, whereas the Zn-deposited graphite-sheet-based Zn//MnO₂ cell short-circuits over 1000 cycles. Therefore, this method can be used for preparing dendrite-free Zn anodes in a scalable and cost-effective manner.