Mediating Lithium Plating/Stripping by Constructing 3D Au@Cu Pentagonal Pyramid Array

Abstract

Lithium (Li) metal is perceived as the “holy grail” of anodes for secondary batteries due to its innate merits. Regrettably, the commercial application of Li metal anodes (LMAs) has been hampered by problems derived from the uncontrollable growth of Li dendrites, which could result in formation of short-circuits, thereby leading to fatal safety accidents. Here, a three-dimensional lithiophilic gold (Au)-coated copper (Cu) pentagonal pyramid array (Au@CuPPA) is constructed on planar Cu foil via electrodeposition followed by a chemical reduction method. Owing to the features of the lithiophilic layer and 3D porous structure, the proposed Au@CuPPA can not only facilitate Li-ion migration and charge transfer, but also effectively diminish the nucleation overpotential. Consequently, an even and steady Li plating/stripping process for up to 460 h and with a charge capacity of 3 mAh cm−2 is accomplished by using the Au@CuPPA current collector. The Li@Au@CuPPA|LiFePO4 full cell achieves a high Coulombic efficiency (CE) of 99.4% for 150 cycles at 0.5 C with a capacity retention of 92.4%.

Keywords

• Li metal anode
• dendrite growth
• current collector
• lithiophilic layer
• Cu array
• pentagonal pyramid