Enhancing the electrochemical performance of Sn-Zn alloy anode foil for lithium-ion batteries through microstructure design via accumulative roll bonding technique

Abstract

In this study, we introduce a novel method for designing microstructures of Sn-45Zn alloy foils utilizing the accumulative roll bonding (ARB) technique, which is one of severe plastic deformation techniques that have been used for refining the microstructures of bulk metals. The electrochemical properties of Sn-Zn foil anodes with various microstructures achieved through the ARB method followed by annealing are investigated in lithium-ion batteries. The degree and characteristics of microstructural damage during electrochemical cyclic tests are also examined in detail to provide insights into the microstructural parameters that critically influence the capacity and cyclic behavior of the Sn-Zn alloy foil anode. Our findings suggest that the ARB-processed Sn-Zn alloy foil, characterized by nearly ultrafine grains composed of Sn and Zn phases with the Zn phase forming a continuous network, exhibits superior battery capacity and cycle life compared to the sample processed using the conventional rolling method. This superiority can be attributed to its unique microstructure obtained through ARB, which reduces pore density, suppresses pore interlinkage, decreases charge transport resistance and nucleation overpotential, and enhances Li-ion diffusivity in the electrode.