A corrosion inhibiting layer to tackle the irreversible lithium loss in lithium metal batteries

Abstract

Reactive negative electrodes like lithium (Li) suffer serious chemical and electrochemical corrosion by electrolytes during battery storage and operation, resulting in rapidly deteriorated cyclability and short lifespans of batteries. Li corrosion supposedly relates to the features of solid-electrolyte-interphase (SEI). Herein, we quantitatively monitor the Li corrosion and SEI progression (e.g., dissolution, reformation) in typical electrolytes through devised electrochemical tools and cryo-electron microscopy. The continuous Li corrosion is validated to be positively correlated with SEI dissolution. More importantly, an anti-corrosion and interface-stabilizing artificial passivation layer comprising low-solubility polymer and metal fluoride is designed. Prolonged operations of Li symmetric cells and Li | |LiFePO₄ cells with reduced Li corrosion by ~74% are achieved (0.66 versus 2.5 μAh h⁻¹). The success can further be extended to ampere-hour-scale pouch cells. This work uncovers the SEI dissolution and its correlation with Li corrosion, enabling the durable operation of Li metal batteries by reducing the Li loss.

Lithium metal electrodes suffer from both chemical and electrochemical corrosion during battery storage and operation. Here, the authors show that lithium corrosion is due to dissolution of the solid-electrolyte interphase and suppress this by utilizing a multifunctional passivation layer.