Molybdenum dialkyphosphorodithioate-derived artificial solid-electrolyte interface enabling stable lithium metal anodes

Abstract

Lithium metal is a promising candidate for next-generation high-energy-density battery systems, but it is hindered by the unstable interface, detrimental side reactions, and uncontrolled dendrite growth. In this paper, a robust organic/inorganic artificial solid-electrolyte interface was constructed based on the mechanochemical reaction between molybdenum dialkyphosphorodithioate (MoDTP) rolling oil and lithium metal under rolling. The interface layer, consisting of organic outer layer (organic polyphosphate, and thiolate) and inorganic inner layer (Li2S, MoS2, Li3PO4, and MoO2), not only inhibits Li dendrite growth effectively due to its excellent mechanical properties (with high Young's modulus of ∼21 GPa), but also enhances Li-ion diffusion with fast ion conductors from the interface. The Li anode rolled by using MoDTP (Li@MoDTP) achieves a stable long-lifespan over 5400 h at 5 mA cm2 and 5 mAh cm2. Meanwhile, the LiFePO4 ||Li@MoDTP full cell also exhibits impressive longevity when pairing with a high single-sided cathode loading of 13 mg cm−2, which lasts over 750 cycles at 1 C rate (1 C = 170 mA g−1). This work sheds lights on producing stable and practical Li metal anodes through mechanical rolling with tailored rolling oils.