ZnF2 coated three dimensional Li-Ni composite anode for improved performance

Abstract

Lithium metal is a promising anode material for high energy density batteries, which is restricted from practical application by the issues including lithium dendrite, parasitic reaction and volumetric change. Herein, a strategy combing bulk and surface modification is proposed to address these problems. The bulk modification is to use Ni foam as three dimensional (3D) scaffold for direct infusion of molten Li resulting in the formation of Li-Ni composite anode, which reduces actual current density by increasing specific surface area and alleviates volumetric change in the process of Li stripping/plating. And the surface modification is to coat with ZnF2 film via sputtering, which is acted as artificial protective layer for controlling interfacial side reaction. The symmetric cell consisting of ZnF2 coated Li-Ni composite electrodes exhibits low overpotential (about 45 mV) and stable cycling over 900 h at 1 mA cm−2. Furthermore, the cell with LiCoO2 cathode delivers 110 mAh g−1 at 1 C rate after 500 cycles. Keywords: Lithium metal anode, Composite lithium, Nickel foam, Lithium dendrite, Surface modification, Lithium battery