Electrosynthesis of Vertically Aligned Zinc Oxide Nanoflakes on 3D Porous Cu Foam Enables Dendrite-Free Li-Metal Anode.

Abstract

Three dimensional (3D) hosts have been recognized as effective current collectors for Li metal anodes because of their physical suppression of the lithium dendrites growth. A lithiophilic surface layer on them could increase the Li metal nucleation sites, further regulating the genuine plating of Li metal. The current strategies to construct this lithiophilic layer on 3D structure is complex and not suitable for the scalable fabrication of Li metal anode. In this work, we developed a facile method to grow vertically aligned ZnO nanoflakes on the surface of 3D Cu foam through an electrochemical synthetic process, which physically suppressed the Li dendrites growth due to the unique structure during the Li plating/stripping process. Moreover, these lithiophilic flakes effectively increase the specific surface area of the anode and Li metal nucleation sites number, which reduces the local current densities, leading to the formation of a robust SEI and further suppressing the Li dendrites growth. Consequently, the performances of the symmetric Li plated Cu foam/Li cell and the Li plated Cu foam/LiFePO4 full cell have been greatly enhanced after the growth of vertically aligned ZnO nanoflakes on the Cu foam surface, including capacity, cycling stability, overpotential, and rate capability.