High-performance Li/LiNi0.8Co0.1Mn0.1O2 batteries enabled by optimizing carbonate-based electrolyte and electrode interphases via triallylamine additive

Abstract

Lithium (Li) metal batteries (LMBs), paired with high-energy–density cathode materials, are promising to meet the ever-increasing demand for electric energy storage. Unfortunately, the inferior electrode–electrolyte interfaces and hydrogen fluoride (HF) corrosion in the state-of-art carbonate-based electrolytes lead to dendritic Li growth and unsatisfactory cyclability of LMBs. Herein, a multifunctional electrolyte additive triallylamine (TAA) is proposed to circumvent those issues. The TAA molecule exhibits strong nucleophilicity and contains three unsaturated carbon–carbon double bonds, the former for HF elimination, the later for in-situ passivation of aggressive electrodes. As evidenced theoretically and experimentally, the preferential oxidation and reduction of carbon–carbon double bonds enable the successful regulation of components and morphologies of electrode interfaces, as well as the binding affinity to HF effectively blocks HF corrosion. In particular, the TAA-derived electrode interfaces are packed with abundant lithium-containing inorganics and oligomers, which diminishes undesired parasitic reactions of electrolyte and detrimental degradation of electrode materials. When using the TAA-containing electrolyte, the cell configuration with Li anode and nickel-rich layered oxide cathode and symmetrical Li cell deliver remarkably enhanced electrochemical performance with regard to the additive-free cell. The TAA additive shows great potential in advancing the development of carbonate-based electrolytes in LMBs.