Coordination Engineering of N, O Co-Doped Cu Single Atom on Porous Carbon for High Performance Zinc Metal Anodes

Abstract

Traditional challenges of poor cycling stability and low Coulombic efficiency in Zinc (Zn) metal anodes have limited their practical application. To overcome these issues, this work introduces a single metal-atom design featuring atomically dispersed single copper (Cu) atoms on 3D nitrogen (N) and oxygen (O) co-doped porous carbon (CuNOC) as a highly reversible Zn host. The CuNOC structure provides highly active sites for initial Zn nucleation and further promotes uniform Zn deposition. The 3D porous architecture further mitigates the volume changes during the cycle with homogeneous Zn2+ flux. Consequently, CuNOC demonstrates exceptional reversibility in Zn plating/stripping processes over 1000 cycles at 2 and 5 mA cm-2 with a fixed capacity of 1 mAh cm-2, while achieving stable operation and low voltage hysteresis over 700 h at 5 mA cm-2 and 5 mAh cm-2. Furthermore, density functional theory calculations show that co-doping N and O on porous carbon with atomically dispersed single Cu atoms creates an efficient zincophilic site for stable Zn nucleation. A full cell with the CuNOC host anode and high loading V2O5 cathode exhibits outstanding rate-capability up to 5 A g-1 and a stable cycle life over 400 cycles at 0.5 A g-1. The 3D porous carbon host with N, O co-doped Cu single atom coordination provides uniform Zn2+ flux channel and highly zincophilic active sites for dendrite-free and reversible Zn deposition. This unique configuration delivers outstanding stability during Zn plating/stripping cycles and low polarization with high CEs. This new engineering design delineates a new trajectory for the practical Zn metal anode applications.image