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

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. Li anode with surface and bulk modification was fabricated by infusion of molten Li into Ni foam and coating with ZnF2 film. The surface modified Li-Ni composite electrode demonstrates excellent electrochemical performance since the surface modification reduces interfacial side reaction and three dimensional Ni scaffold suppresses the growth of Li dendrite. [Display omitted] •The strategy of both bulk and surface modification is proposed for suppressing lithium dendrite.•Surface modification with ZnF2 film as artificial SEI reduces interfacial side reaction.•The excellent performance (stable cycling for 600 cycles) of symmetric cell was achieved at extreme current density.