Electrochemical-Thermal Effect on Lithium Plating and Cell Failure

Abstract

Lithium plating is a detrimental process occurring in the anode of lithium-ion batteries. Plating usually occurs when the rate of incoming lithium flux exceeds the rate of intercalation at the graphite anode. Research over the past years have identified common triggers for lithium plating as low temperature, high rate charging and high states of charge due to reduced lithium ion diffusivity or increased charge transfer resistance in these conditions. One common method proposed to overcome the reduced diffusivity issues is high temperature charging. In this study, pouch cells were cycled at different temperatures to see how plating evolves with aging. Although, cells cycled at high temperature show minimal plating in the beginning of cycling, increasing amounts of plating is observed in the cell with cycling. Although operating at high temperatures aids with the diffusion of lithium ions other secondary aging mechanisms such as the solid electrolyte interphase (SEI) growth and passivation of plated lithium are accelerated leading to cell failure. A combination of electrochemical and material characterization methods is employed to identify the operational interplay of temperature and plating using three-electrode pouch cells. Operando anode potential measurements were used to identify whether lithium plating is the cause or consequence of cell failure.