Manipulating the Potential Diagram for Better Lithium–Metal Batteries

Abstract

Achieving high reversibility in Li-metal batteries, promising candidates for high-energy-density storage systems, remains a major challenge. This study addresses this by optimizing a full-cell potential diagram based on electrolyte energetics. Variations in Coulomb interactions among Li⁺, anions, and solvents in the electrolyte can affect (1) the electrostatic potential (liquid Madelung potential) of Li⁺, which can shift both the anode and cathode reaction potentials by the same magnitude; and (2) the operating potential window of the electrolyte, which can cause kinetic hindrance via the formation of a passivation film on the electrode. Systematically balancing these factors based on quantitative experimental results can enhance the performance of the Li-metal battery while minimizing electrolyte degradation at the electrode surface. These insights into the fundamental role of electrolyte energetics in battery design are expected to contribute to the development of comprehensive frameworks for highly stable high-energy-density storage devices.