Progressive deposition on carbon nanofiber films enables dendrite-free zinc plating

Zinc anodes tend to form irregular and non-planar electrodeposits during repeated cycles, leading to the dendrite growth and consequently resulting in internal short circuits of Zn-based batteries and security problems. A progressive deposition is investigated in the present study by introducing oxygen functional groups and macropores into the carbon nanofiber film to regulate the nucleation and growth of Zn. Experimental analyses and theoretical simulation show that zincophilic oxygen functional groups act as preferred deposition sites with ultralow Zn nucleation overpotential to guide the initial nucleation of Zn on the whole surface of carbon nanofibers. The macropores with higher Zn2+ concentration and current density serve as the preferred paths for the subsequent growth of Zn inside. Deposited Zn will progressively fill the internal void space of the entire carbon nanofiber film. The carbon nanofiber film with the progressive deposition enables dendrite-free Zn plating/stripping. Symmetric cells with OPCNF-Zn electrodes exhibit a long cycle life over 1300 h at 1 mA cm−2 for 1 mA h cm−2.