A Perspective on Dissolved Transition Metal Species in Li-Ion Batteries: Causes, Speciation, Movement, and Impact

Abstract A myriad of studies within the battery community have associated transition metal (TM) dissolution with poor cell performance. Our current understanding is that dissolved TMs degrade electrolyte salts and solvents and destroy the passivating nature of the solid electrolyte interphase (SEI), resulting in continuous electrolyte consumption and changes to the SEI’s chemical composition. These processes cause performance decline and make battery lifetime predictions challenging. Largely overlooked in the literature, however, is that a portion of these dissolved TMs redeposit on the cathode surface. Key questions about the driving forces and impact of TM redeposition on the cathode surface remain unanswered. Addressing these scientific inquiries is crucial, as the manipulation of TM dissolution/redeposition dynamics could be used to engineer battery interfaces and improve battery cycle life with minimal expense.