Ultrahigh‐Capacity and Long‐Life Lithium–Metal Batteries Enabled by Engineering Carbon Nanofiber–Stabilized Graphene Aerogel Film Host

Abstract A safe, high‐capacity, and long‐life Li metal anode is highly desired due to recent developments in high‐energy‐density Li–metal batteries. However, there are still rigorous challenges associated with the undesirable formation of Li dendrites, lack of suitable host materials, and unstable chemical interfaces. Herein, a carbon nanofiber‐stabilized graphene aerogel film (G‐CNF film), inspired by constructional engineering, is constructed. As the host material for Li deposition, the G‐CNF film features a large surface area, porous structure, and a robust skeleton that can render low local current density. This allows for dendrite‐free Li deposition and mitigation of problems associated with large volume change. Importantly, the G‐CNF film can keep high Li plating/stripping efficiency at nearly 99% for over 700 h with an areal capacity of 10 mA h cm −2 (the specific capacity up to 2588 mA h g −1 based on the total mass of carbon host and Li metal). The symmetric cells can stably run for more than 1000 h with low voltage hysteresis. The full cell with the LiFePO 4 cathode also delivers enhanced capacity and lowered overpotential. As two‐in‐one host materials for both cathodes and anodes in Li–O 2 batteries, the battery exhibits a capacity of 1.2 mA h cm −2 .