Scalable Surface Application of Stabilized Lithium Metal Particles (SLMP) for Enhancing Silicon-Based Anode in Full-Cell Lithium-Ion Batteries

Silicon has been considered as one of the most promising replacements for graphite anodes in next-generation lithium-ion batteries due to its superior energy density. However, one prominent issue with silicon-based anode materials is the substantial consumption of lithium ions due to the large volume expansion of silicon upon lithiation and the continuous formation of the solid-electrolyte interphase. In a full-cell setting where silicon is paired with a commercial cathode, this irreversible consumption of lithium ions is especially detrimental to the limited lithium-ion reserve of the system, leading to a low first-cycle Coulombic efficiency and a shortened cycle life. Several pre-lithiation strategies have been explored to mitigate this problem, and the use of stabilized lithium metal particles (SLMP) is being demonstrated as a practical pre-lithiation method compatible with scaled-up industrial applications. Particularly, a SLMP slurry was designed with hexanes as a compatible solvent and a nonionic surfactant additive at 1%wt serving as the stabilizer for maintaining a uniform SLMP suspension. This slurry was then spray-coated onto the prefabricated silicon electrode, forming a uniformly distributed and well adhered SLMP layer on the surface. By optimizing the amount of SLMP being applied, we are able to demonstrate improvements in the electrochemical performance of silicon-based full-cell batteries with both increased first-cycle Coulombic efficiency and capacity retention. We will also attempt to provide a description of SLMP’s effects at the electrode surface throughout the electrochemical cycling of the batteries.