Differential Capacity Voltage Relaxation Analysis for Detecting Low Temperature Plating
Differential capacity voltage relaxation analysis detects sub-zero lithium plating by identifying chemical re-intercalation peaks during post-charge rest.
Low Temperature Lithium Plating
Meaning
Undesirable electrodeposition of metallic lithium onto the surface of negative host electrodes occurs when charging currents drive the local anode potential below the lithium equilibrium potential at low temperatures. Low temperature lithium plating consumes active cyclable lithium, degrades capacity retention and creates severe thermal runaway hazards through dendrite penetration across porous separators. The term covers metallic electrodeposition on intercalation anodes and does not apply to intentional lithium deposition in pure lithium-metal anode architectures.
Plating Mechanism
Subzero temperatures severely diminish the rate of lithium ion desolvation and solid-state diffusion within graphite particles. When the charging current delivers ions to the electrode surface faster than they can intercalate into the carbon lattice, local negative electrode potential drops below zero volts versus lithium. Under this electrochemical condition, metallic lithium nucleates directly on graphite particle surfaces instead of intercalating safely into the carbon layers.
Safety Hazards
Deposited lithium exists in highly reactive mossy or dendritic morphologies that react continuously with liquid electrolyte, generating thick, non-conductive passivation layers that dry out the cell. Continued dendritic growth can pierce separator membranes, creating direct internal short circuits that initiate catastrophic thermal runaway. Part of the plated lithium becomes electrically isolated dead lithium, causing irreversible capacity fade that cannot be recovered through cell resting.
Procurement Requirements
Purchasers of lithium-ion cells for automotive and industrial applications mandate extensive cold-temperature cycle testing to verify that supplier-defined charging protocols do not induce plating. Factory acceptance criteria require non-destructive differential voltage analysis and destructive teardowns after 100 fast-charge cycles at subzero temperatures to verify zero metallic accumulation. Cell suppliers must present validated charging algorithms that dynamically throttle current based on real-time cell temperature to prevent lithium deposition.