Homogenous metallic deposition regulated by abundant lithiophilic sites in nickel/cobalt oxides nanoneedle arrays for lithium metal batteries

Abstract

Although lithium (Li) metal delivers the highest theoretical capacity as a battery anode, its high reactivity can generate Li dendrites and “dead” Li during cycling, resulting in poor reversibility and low Li utilization. Inducing uniform Li plating/stripping is the core of solving these problems. Herein, we design a highly lithiophilic carbon film with an outer sheath of the nanoneedle arrays to induce homogeneous Li plating/stripping. The excellent conductivity and 3D framework of the carbon film not only offer fast charge transport across the entire electrode but also mitigate the volume change of Li metal during cycling. The abundant lithiophilic sites ensure stable Li plating/stripping, thereby inhibiting the Li dendritic growth and “dead” Li formation. The resulting composite anode allows for stable Li stripping/plating under 0.5 mA cm−2 with a capacity of 0.5 mA h cm−2 for 4000 h and 3 mA cm−2 with a capacity of 3 mA h cm−2 for 1000 h. The Ex-SEM analysis reveals that lithiophilic property is different at the bottom, top, or channel in the structure, which can regulate a bottom-up uniform Li deposition behavior. Full cells paired with LFP show a stable capacity of 155 mA h g−1 under a current density of 0.5C. The pouch cell can keep powering light-emitting diode even under 180° bending, suggesting its good flexibility and great practical applications.