A highly stable host for lithium metal anode enabled by Li9Al4-Li3N-AlN structure

Highlights: • A cross-linked Li₉Al₄-Li₃N-AlN (LLA) structure is synthesized as a stable host for Li metal anode; • The LLA structure exhibits a high capacity of 1540 mAh g⁻¹ and 1600 mAh cm⁻³ enabled by uniform Li plating/stripping; • High capacity retention of 90.1% is achieved for a Li@LLA||LiNi_0.8Co_0.1Mn_0.1O₂ full cell at the 200th cycle. -- Abstract: Lithium (Li) metal battery is one of the ideal candidates for the next-generation high-energy-density batteries, but its practical application is still plagued by its large volume change, low coulombic efficiency (CE), and safety issues related to dendrite growth. This work describes a potential solution to these issues using a cross-linked Li₉Al₄-Li₃N-AlN (LLA) structure as a stable host for Li metal anode. The in situ-formed uniform Li₉Al₄ and Li₃N sites on AlN nano-clusters can suppress dendrite growth during the Li plating/stripping process. The intrinsic lithiophilicity of Li₉Al₄ sites with adjacent Li₃N attracts Li⁺ ions for fast migration and uniform plating/stripping. These unique features lead to dimensional stability of Li@LLA composite anodes (1540 mAh g⁻¹ and 1600 mAh cm⁻³). High-rate, high-capacity cycling of Li metal anodes has been maintained with a CE of ~98% in carbonate-based electrolytes. High capacity retention of 90.1% is achieved for a Li@LLA||LiNi_0.8Co_0.1Mn_0.1O₂ full cell at the 200th cycle. Therefore, the LLA structure with a simple fabrication process could be a promising candidate to enhance the safety of next-generation Li metal batteries.