The Polymer Society of Korea

Abstract

To address the critical challenges of dendritic growth and low reversibility in anode-free sodium batteries, we propose a structured current collector that enables horizontal sodium plating through sodiophilicity-guided design. By vertically coating gold on periodically aligned carbon pillar arrays, we exploit the strong affinity between sodium and gold to direct nucleation and growth along the lateral pillar interfaces. The horizontally grown sodium fills the inter-pillar voids up to the pillar height, enabling a host volume matched to the target areal capacity. In this triphasic system composed of carbon, gold, and copper, we analyzed the initial sodium storage and plating behavior using cyclic voltammetry to elucidate the role of each component. Through this arrangement of materials with contrasting sodiophilicity, our strategy enables stable cycling over 600 hours at 5 mA cm^-2 in half-cell configurations and demonstrates applicability in full-cell systems.