Efficient Zn Metal Anode Enabled by O,N-Codoped Carbon Microflowers

Zinc metal anodes show great promise for cheap and safe energy storage devices. However, it remains challenging to regulate highly efficient Zn plating/stripping under a high depth of discharge (DOD). Guided by density functional theory calculation, we here synthesized an oxygen- and nitrogen-codoped carbon superstructure as an efficient host for high-DOD Zn metal anodes through rational monomer selection, polymer self-assembly, and structure-preserved carbonization. With microscale 3D hierarchical structures, microcrystalline graphitic layers, and zincophilic heteroatom dopants, a flower-shaped carbon (C_flower) host could guide Zn nucleation and growth in a heteroepitaxial mode, affording horizontal plating with a high Coulombic efficiency (CE) and long life. As a demonstration, the C_flower-hosted Zn anode was paired with both battery and supercapacitor cathodes and delivered large capacity/capacitance, fast rates, long life, and ca. 100% CE even under a high DOD, outclassing hostless Zn-based devices. As they possess cheap, scalable, and efficient features, C_flower hosts hold the potential for practical zinc-metal-based energy devices.