Porous Sn foil anodes with elongated pore architecture for high specific capacity and stability in lithium-ion batteries

Abstract

This study presents the development of high-capacity porous tin (Sn) metal foils as advanced anodes for lithium-ion batteries. The porous Sn foils are fabricated through rolling and chemical dealloying of a Sn-45Zn alloy. This process results in a porous architecture that enhances electrolyte infiltration, promotes uniform lithiation/delithiation, and improves lithium-ion diffusivity. Additionally, this porous structure reduces charge transfer resistance, lowers overpotential, and accommodates volume changes during cycling by facilitating the stepwise formation of intermediate phases. Optimizing pore morphology, particularly through elongated pores, is crucial for maximizing performance and durability. Elongated pores reduce stress concentrations around their edges and tips compared to round pores, thereby minimizing cracking and pore collapse. Furthermore, they can enhance mechanical stability by effectively accommodating and distributing plastic deformation induced by volume expansion. At an optimal porosity of 45 %, this porous architecture offers an ideal balance between surface area and mechanical integrity. The elongated porous Sn foil electrodes exhibit an excellent balance between specific and volumetric capacity, outperforming both bulk metallic and other porous metal foil anodes.