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.

Rational Molecular Engineering via Electron Reconfiguration toward Robust Dual-Electrode/Electrolyte Interphases for High-Performance Lithium Metal Batteries

“…Cryogenic transmission electron microscopy (cryo-TEM) has shown tremendous potential on characterizing beam-sensitive and air-reactive battery materials in subangstrom resolution. − Hence, it was carried out to visualize the chemical composition and spatial structure of the SEI to understand the mechanism of the SN additive for Li metal protection. The SEI formed in BCE possess an irregular and thick morphology (37 nm), which is mainly composed of amorphous phase (Figure a).…”

Lithium-ion battery cell formation: status and future directions towards a knowledge-based process design

“…127,296,299,300 Due to the higher solubility of organic species, dissolution is more pronounced for solvent-derived SEIs, which may also result in accelerated aging. 296,301–303 By choosing a suitable solvent, the solubility of the SEI species in the electrolyte can also be used to selectively dissolve unfavourable species and form an SEI with a higher content of inorganic species. 304…”

Synergistic Effect of CO2 in Accelerating the Galvanic Corrosion of Lithium/Sodium Anodes in Alkali Metal–Carbon Dioxide Batteries

“…30 Unfortunately, recent cryo-electron microscopy results from Jin et al demonstrate that the as-formed SEI suffers a dynamic progression of repeated swelling, dissolution, breakage, and reformation, leaving Li anode exposed to electrolytes and its continuous Li corrosion. 31 In addition, Boyle et al reveal that the chemical corrosion of Li could still occur due to the inhomogeneity in the solubility and electronic conductivity of the as-formed SEI. 32 Moreover, a recent study from Lu et al provides additional insights regarding the Li chemical corrosion, and they discover that the corrosion rate is dominated by the porosity of the deposited Li, with a larger porosity of the deposited Li possessing a faster corrosion rate.…”

“…Recently, the galvanic (also called bimetallic) corrosion, which has been largely overlooked in previous corrosion studies, has been raising substantial attention in the battery community. , During the galvanic corrosion, the metal with a lower standard electrode potential (anode) is oxidized, while the released electrons flow to the metal with a higher standard electrode potential (cathode), therein the reduction process occurs. , It is the electromotive force resulting from these two different metals (galvanic couple) that accelerates the oxidation of the anode in the presented galvanic couple. The terminology “galvanic element” is used to describe a system consisting of a galvanic couple exposed to electrolytes .…”

“…This kinetic suppression of further chemical corrosion by the passivating SEI depends to a large extent on the composition, structure, and even morphology of the generated SEI . Unfortunately, recent cryo-electron microscopy results from Jin et al demonstrate that the as-formed SEI suffers a dynamic progression of repeated swelling, dissolution, breakage, and reformation, leaving Li anode exposed to electrolytes and its continuous Li corrosion . In addition, Boyle et al reveal that the chemical corrosion of Li could still occur due to the inhomogeneity in the solubility and electronic conductivity of the as-formed SEI .…”