Efficient Zn Metal Anode Enabled by O,N-Codoped Carbon Microflowers
Zhixiao Xu, Song Jin, Nianji Zhang, Wenjing Deng, Min Ho Seo, Xiaolei Wang
Abstract
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 (Cflower) 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 Cflower-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, Cflower hosts hold the potential for practical zinc-metal-based energy devices.