An Alternative to Lithium Metal Anodes: Non-dendritic and Highly Reversible Sodium Metal Anodes for Li-Na Hybrid Batteries.

Highly reversible, stable, and non-dendritic metal anode (Li, Na etc.) is a crucial requirement for next-generation high-energy batteries. Herein, we have built a Li-Na hybrid battery (LNHB) based on Na plating/stripping, which features a high and stable coulombic efficiency of 99.2 % after 100 cycles, low voltage hysteresis (42 mV at 2 mA cm-2 ), and fast charge transfer. As a result of the Li+ electrostatic shield layer, the Na deposition showed cubic morphology rather than dendritic, even at high current density of 5 mA cm-2 . The solvation/desolvation of Li+ and Na+ were modelled by density functional theory calculations, demonstrating the fast desolvation kinetics of Na+ . Owing to the superior performance of the Na metal anode, the LNHB coupled with LiFePO4 cathode exhibited low voltage hysteresis and stable cycling performance that demonstrates its feasibility in practical applications.