Synchronous Healing of Li Metal Anode via Asymmetrical Bidirectional Current

The creation of Li metal anodes while minimizing dendrite growth is an important challenge for developing high-energy density batteries. Dendrites can originate from an inhomogeneous charge distribution or an irregular substrate, and often, the way to suppress dendrite growth is to avoid their formation altogether (ion-uniform mechanism over a shelf time). Herein, we propose a different route to eliminate dendrite formation, called an asymmetrical bidirectional current mode (ABCM) of charging, leading to a healable Li metal anode and resulting in a positive feedback cycle. This mode allows for a stable cyclic performance and suppresses dendrite formation effectively (while holding the polarization ∼27 mV for over 1,000 h), and provides a better result than suppressing Li dendrites via weakening of the Li dendrite (ion-uniform mechanism). These results indicate that ABCM may be a promising way to stabilize the Li anode of Li metal batteries, without any chemical/physical modification of the anode.