lithiumplating

Lithium plating refers to the deposition of metallic lithium on the anode surface of a lithium-ion battery, instead of lithium ions intercalating into the anode material, typically graphite. This plating can occur during charging when the rate of lithium reduction exceeds the rate at which lithium ions can be intercalated, or under conditions that slow intercalation such as low temperatures, high charging current, or high electrode potentials.

The process is influenced by kinetic and transport factors, including temperature, electrolyte composition, and the cycling protocol. When plating happens, plated lithium can form dendritic structures that extend toward the electrolyte and separator. These dendrites increase the risk of internal short circuits, capacity loss, and rising impedance. In addition, plated lithium may become isolated from the electrode during cycling, creating dead lithium and contributing to accelerated aging.

Consequences of lithium plating include reduced coulombic efficiency, accelerated capacity fade, higher cell impedance, and, in the worst case, thermal runaway due to short circuits or electrolyte decomposition at high local temperatures. Plating is a particular concern for graphite anodes in conventional lithium-ion chemistries and can be more pronounced at very low temperatures or during aggressive fast charging.

Detection and assessment of plating involve electrochemical indicators such as a drop in coulombic efficiency, changes in voltage profiles, and post-mortem analyses using microscopy or tomography to visualize metallic lithium and dendrites. In situ techniques and impedance measurements can provide early warning.

Prevention strategies focus on operating within safe temperature and charging limits, optimizing electrolyte formulations and additives to form stable interfaces, and exploring alternative anode materials or solid-state electrolytes that mitigate plating risk. See also electrolyte, SEI, and fast charging.