Competitive Roles of Conductivity and Lithiophility in Composite Lithium Metal Anode

Abstract

For the three-dimensional conductive host, the uneven lithium deposition and the dependence on the pore structure and lithiophility are a great challenge for lithium metal anodes. Herein, we employed facial chemical etching techniques on brass foil to fabricate three-dimensional copper hosts with diverse pore structures and lithiophilities, thus intending to understand the lithium depositing mechanisms in porous hosts. The copper host with a more pronounced pore structure exhibits the lower polarization voltage induced by its large specific surface area, which reduces the local current density and provides a great deal of pathway for lithium ion diffusion. Meanwhile, it exhibits high nucleation overpotential and a short lifespan due to a reduced number of favorable lithium nucleation sites caused by the reduced lithiophilic zinc sites and a marked increase in the routes between nucleation sites. Therefore, the appropriate pore structure needs a consideration of efficient balance between the nucleation overpotential, the polarization voltage, and Coulombic efficiency. This insight underscores the pivotal role of well-suited pore structures in three-dimensional hosts, providing profound guidance for the efficient design of advanced host for lithium metal anode.