Cobalt‐Phthalocyanine‐Derived Molecular Isolation Layer for Highly Stable Lithium Anode

Abstract

AbstractThe uneven consumption of anions during the lithium (Li) deposition process triggers a space charge effect that generates Li dendrites, seriously hindering the practical application of Li‐metal batteries. We report on a cobalt phthalocyanine electrolyte additive with a planar molecular structure, which can be tightly adsorbed on the Li anode surface to form a dense molecular layer. Such a planar molecular layer cannot only complex with Li ions to reduce the space charge effect, but also suppress side reactions between the anode and the electrolyte, producing a stable solid electrolyte interphase composed of amorphous lithium fluoride (LiF) and lithium carbonate (LiCO3), as verified by X‐ray absorption near‐edge spectroscopy. As a result, the Li|Li symmetric cell exhibits excellent cycling stability above 700 h under a high plating capacity of 3 mAh cm−2. Moreover, the assembled Li|lithium iron phosphate (LiFePO4, LFP) full‐cell can also deliver excellent cycling over 200 cycles under lean electrolyte conditions (3 μL mg−1).