Constructing artificial solid electrolyte interphase by facile chemical reaction for stable lithium metal anodes

Lithium metal is considered one of the most promising anode materials because of its high theoretical capacity and the lowest electrode potential, but practical application is hampered by high reactivity and volume variation in circulation. As a key component, the artificial solid electrolyte interphase (SEI) is designed to effectively stabilize the lithium anode. Here, the chemical reaction between dimethyl sulfoxide (DMSO) and lithium is accelerated in the presence of potassium hydroxide (KOH). The sulfur-containing organic compounds, lithium sulfate (Li2SO4), lithium hydroxide (LiOH) and other favorable components are introduced into SEI, which enable the modified lithium metal anode to have lower interfacial impedance, higher lithium ion transference number, and more uniform Li-ion deposition. The assembled Li-Li symmetric battery realizes a stable cycle of more than 800 h at a current density of 0.5 mA cm-1 and an areal capacity density of 1 mAh cm-1. The full cell coupled with LiNi0.6Co0.2Mn0.2O2 (NCM622) still maintains 113 mAh g-1 discharge capacity with 63% capacity retention rate after 400 cycles at a current density of 0.5 C. The simple construction of artificial SEI strategy of this study provides an effective strategy for LMBs with superior electrochemical performance.

Automated summary

Due to the high reactivity and volume variation of lithium metal, its practical application is limited. This study successfully improves the electrochemical performance of lithium metal by accelerating the chemical reaction between dimethyl sulfoxide (DMSO) and lithium, and introducing sulfur-containing organic compounds into the artificial solid electrolyte interphase (SEI).