Oscillatory solvation chemistry for a 500 Wh kg−1 Li-metal pouch cell

Abstract

Cation solvation is well understood in the bulk solution phase, but knowledge is limited regarding the electrode–electrolyte interface. The process by which cation solvation conforms to the interfacial field to form interphases remains unclear. Here we examine the synergistic effects of external and intramolecular fields on accommodating Li+ solvates to the Li-metal anode, leading to dielectric-mediated transfer dynamics on the interface. At charged interfaces, cation–anion pairs arrange in a periodic oscillatory distribution. A low-oscillation amplitude exacerbates the electrolyte decomposition and increases surface impedance. We propose a dielectric protocol that maintains cation–anion coordination with a high oscillation amplitude at the interfaces, addressing these issues. Accordingly, we demonstrate a Li-metal pouch cell with an energy density of 500 Wh kg−1 at the Ah level using an ultra-lean electrolyte (1 g Ah−1). Our study offers insights into solid/liquid interfaces that are crucial in advancing battery technologies. Cation solvation in batteries is well understood in bulk solutions but less so at electrode/electrolyte interfaces. This study reveals how external and intramolecular fields affect Li-ion solvation, proposing a dielectric protocol to enhance cation–anion coordination and improve performance in Li-metal pouch cells.