The present invention relates to a pyridyl additive, a
nitrile-based
electrolyte containing the pyridyl additive, and a
lithium metal secondary battery, belonging to the technical field of
lithium metal secondary batteries. To solve the problems that the existing
nitrile-based electrolytes are prone to increasing the
desolvation energy and forming a
mass transfer-
inert interfacial film, the present invention provides a pyridyl additive obtained by substituting the hydroxyl group on the
pyridine molecule with at least one strong
electron-withdrawing group, and the strong
electron-withdrawing group includes one or more of -F, -Cl, -Br, -SO3 or -NO2. The present invention uses a
pyridine molecule substituted with a strong
electron-withdrawing group. Through the electron-withdrawing
inductive effect, the positive and
negative charge centers of the
pyridine molecule are separated, increasing the molecular
dipole moment, thereby promoting the adsorption of the additive molecule on the
lithium metal surface, reducing the interfacial
nitrile molecule concentration, enhancing the
electrode /
electrolyte interface stability, reducing the interfacial lithium
ion desolvation energy, enhancing the interfacial lithium
ion conversion
kinetics, and promoting the uniform deposition of lithium.