Enhancing cycling stability in NaǁZn liquid metal batteries with Fe- based foam negative current collectors

Abstract

The corrosion resistance of the current collector seriously affects the capacity and stable cycling of liquid metal batteries (LMBs). This investigation explores the interface reactions and electrochemical properties between Ni-Fe and Fe foam negative current collectors and the liquid negative metals in Na|NaCl-CaCl₂|Zn LMB. The results elucidate that Ni-Fe foam is erroded and the corrosion products of Ca₂Ni_5, and Ni₂Zn₁₁ are formed on the surface. It accelerates the deposition of Zn and the dissolution of Ni-Fe matrix, thereby leads to a decreation in discharge capacity of the battery. Specifically, the Na/NF‖Zn LMB exhibits a capacity degradation rate of 0.12% over 80 cycles at a current density of 100 m A cm^− 2. However, the emergence of a Fe-Zn alloy on the Fe foam augments the corrosion resistance of the collector and the lifespan of the battery. This is evidenced by the Na/F‖Zn LMB maintaining 97.2% of its initial capacity after 328 cycles, which translates to a minuscule capacity attenuation rate of merely 0.00854%/ per cycle. This study further improves the perfomence of the negative current collector for NaǁZn LMBs, and provids a better candidate materials for the large-scale application of energy storage batteries.