In Situ Electrochemical Interfacial Manipulation Enabling Lithiophilic Li Metal Anode with Inorganic-Rich Solid Electrolyte Interphases for Stable Li Metal Batteries

Abstract

Lithium-metal anodes (LMAs) are the ultimate choice for realizing high-energy-density batteries; however, its use is hindered by problematic Li growth in the form of dendrites. To alleviate dendritic Li growth, the preparation of LMAs with a lithiophilic current collector (CC) is effective; however, applying a lithiophilic CC to LMAs is still challenging due to the manufacturing complexity involved in the separate lithiophilic treatment and lithiation processes. Herein, a facile one-pot LMA fabrication method by utilizing thiourea (TU) as a precursor is proposed. A lithiophilic Cu₂S layer is formed on Cu foam (CF) by the in situ electrochemical oxidation of TU (Cu_xSCF), and the lithiation of CC is performed via subsequent Li electrodeposition (Li@Cu_xSCF). The Cu₂S on Cu_xSCF can lead to uniform Li deposition by providing lithiophilic sites, and it is converted to form ionic-conductive Li₂S-rich solid electrolyte interphase layer. Resultantly, Cu_xSCF significantly enhances the cycling performance of LMAs compared to CF. Specifically, a LiFePO₄/Li@Cu_xSCF full-cell lithium-metal battery (LMB) with a low n/p ratio (1.6) exhibits capacity retention of 95.6% at 0.5 C (220 cycles) and can maintain 85.0% of initial capacity (425 cycles, n/p = 4) at 2.0 C. LMBs with LiNi_0.6Co_0.2Mn_0.2 and LiNi_0.8Co_0.1Mn_0.1 also exhibit improved electrochemical performance.