Asymmetrical Functionalization of Polarizable Interface Restructuring Molecules for Rapid and Longer Operative Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) have been recognized as high-energy storage alternatives; however, problematic surface reactions due to dendritic Li growth are major obstacles to their widespread utilization. Herein, a 3-mercapto-1-propanesulfonic acid sodium salt (MPS) with asymmetrically functionalized thiol and sulfonate groups as polarizable interface-restructuring molecules is proposed to achieve rapid and longer-operating LMBs. Under a harsh condition of 5 mA cm−2, Li–Li symmetric cells employing MPS can be cycled over 1200 cycles, outperforming those employing other molecules symmetrically functionalized by thiol or sulfonate groups. The improved performance of the Li|V2O5 full cell is demonstrated by introducing MPS additives. MPS additives offer advantages by flattening the surface, reconfiguring Li nucleation and growth along the stable (110) plane, and forming a durable and conductive solid–electrolyte interface layer (SEI). This study suggests an effective way to develop a new class of electrolyte additives for LMBs by controlling engineering factors, such as functional groups and polarizable properties.