Gradient LiCl‐LiF‐LiIn Solid‐Electrolyte‐Interphase for Dendrite‐Free Li‐Metal Anode

ABSTRACT Building a robust artificial composite interphase layer is a promising approach for stabilizing lithium‐metal anode, however, fully exploiting the synergistic effects of composite structures and developing scalable manufacturing methods are the keys to optimizing battery performance and promoting practical applications. Here, we propose a ternary heterostructural gradient design, and develop a universal chemical metathesis to in‐situ constructing a gradient LiCl‐LiF‐LiIn composite interphase layer onto lithium‐metal. This composite layer exhibits an interpenetrated gradient structure with controllable morphology and thickness. The modified electrode shows a plat and dense interface layer, with its structure presenting a heterogeneous, vertically oriented components, which bears low interfacial impedance, rapid Li‐ion diffusion dynamics and high electrochemical stability, thus enabling fast charge‐transfer and uniform Li plating/stripping, finally suppressing side‐reactions and Li‐dendrites. Consequently, the lithium electrode cyclability can be markedly enhanced. Symmetric cells of modified lithium electrode achieve 1600 h stable cycling at 1 mA cm −2 current density, and asymmetric cells coupled with high‐loading LiFePO 4 or LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes show significantly improved cycle‐life (500 cycles of modified Li//LiFePO 4 vs. 205 cycles of bare Li//LiFePO 4 , and 300 cycles of modified Li//LiNi 0.8 Co 0.1 Mn 0.1 O 2 vs. 128 cycles of bare Li//LiNi 0.8 Co 0.1 Mn 0.1 O 2 ). This gradient heterostructural concept would invoke a paradigm shift to future lithium‐electrode interface technologies.