Method for operating a lithium secondary battery

Two-step lithium deposition charging technique using low-current nucleation followed by high-current plastic deformation

This technology is a battery operation method that forms a layer of linear lithium deposits with a small surface area by first creating spherical or hemispherical lithium nuclei at a low current density on the anode current collector, then switching to a high current density to induce plastic deformation.

Lithium metal anodes have historically faced issues with lithium dendrite growth and continuous side reactions at the lithium-electrolyte interface. These challenges have resulted in low coulombic efficiency, short battery lifespan, and reduced energy efficiency.

This technology divides the charging process into two stages: a first current density stage at 0.1–0.3 times the average current density, and a second stage at 1.5–2 times the average. The initial lithium nuclei are subjected to plastic deformation by the subsequent high current. The resulting 2–3㎛ wide linear lithium deposits minimize contact with the electrolyte, significantly reducing side reactions. Applicable to anode-free lithium secondary battery charging protocols, BMS charging algorithms, and battery formation processes, this method boosts coulombic efficiency by adjusting the charging current sequence without requiring changes to cell materials.

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Key Features:

• Providing a lithium secondary battery comprising a cathode, an anode including an anode current collector, and a liquid electrolyte containing a lithium salt and a solvent
• Charging at a first current density where lithium nuclei grow into spherical or hemispherical shapes to form a plurality of lithium nuclei on the anode current collector
• Charging at a second current density higher than the first to induce plastic deformation of the lithium nuclei, thereby forming a lithium deposit layer
• Discharging the lithium secondary battery with the lithium deposit layer to oxidize at least a portion of the layer

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