LiI/Cu Mixed Conductive Interface via the Mechanical Rolling Approach for Stable Lithium Anodes in the Carbonate Electrolyte.

Abstract

The nonuniform ion/charge distribution and slow Li-ion diffusion at the Li metal/electrolyte interface lead to uncontrollable dendrites growth and inferior cycling stability. Herein, a simple mechanical rolling method is introduced to construct a mixed conductive protective layer composed of LiI and Cu on the Li metal surface through the replacement reaction between CuI nanoflake arrays and metallic Li. LiI can promote Li+ transportation across the interface, achieving homogeneous Li+ flux and suppressing the growth of Li dendrite, while the homogeneously dispersed Cu nanoparticles can offer abundant nucleation sites for Li deposition, resulting in a remarkably homogenized charge distribution. As expected, Li metal with the LiI/Cu protection layer (LiI/Cu@Li) exhibits a significantly prolonged lifespan over 350 h with slight polarization at a deposition capacity of 3 mAh cm-2 in the carbonate electrolyte. Besides, when matched with high mass loading LiFePO4 cathodes (20 mg cm-2), the LiI/Cu@Li anodes exhibit much improved cycle stability and rate performance. Highly scalable preparation processes as well as the impressive electrochemical performances in half cells and full cells indicate the potential application of the LiI/Cu@Li anode.