Silicon-stabilized lithium metal powder (SLMP) composite anodes for fast charging by in-situ prelithiation

초록

Advanced battery properties, such as high specific energy density and fast charging, are currently in demand owing to the expansion of the electric vehicle (EV) market. Si and Li metals have attracted research attention as anode materials because of their large theoretical capacities and fast reaction rates with Li ions. However, extreme volume changes and solid electrolyte interphase (SEI) issues hinder their applications in EVs. Herein, we mix Si with stabilized lithium metal powder (SLMP) to achieve a composite anode with complementary characteristics of Si and SLMP (SiLP) that does not require carbon additives. Prelithiation is performed before applying an external current to contribute to a fast reaction rate because of the exclusion of the Si lithiation process and the plating process conducted during the initial charging state. Furthermore, a stable lithium fluoride layer is formed to mitigate SEI issues by adding a fluorinated polymer during electrode fabrication. Capacity characteristics are improved by more than double and a high SiLP anode initial Coulombic efficiency (ICE) of 70% is attained. In addition, the diminished SiLP adsorption energy is provided via density functional theory (DFT) calculations.

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