Acid-scavenging functional separators for power performance of lithium ion electrochemical cells

Abstract

Methods of scavenging acid in a lithium-ion electrochemical cell are provided. An electrolyte solution that contains an acid or is capable of forming the acid is contacted with a polymer comprising a nitrogen-containing acid-trapping moiety selected from the group consisting of: an amine group, a pyridine group, and combinations thereof. The nitrogen-containing acid-trapping moiety scavenges acidic species present in the electrolyte solution by participating in a Lewis acid-base neutralization reaction. The electrolyte solution comprises a lithium salt and one or more solvents and is contained in the electrochemical cell that further comprises a first electrode, a second electrode having an opposite polarity from the first electrode, and a porous separator. Lithium ions can be cycled through the separator and electrolyte solution from the first electrode to the second electrode, where acid generated during the cycling is scavenged by the polymer comprising a nitrogen-containing acid-trapping moiety.