Two-Part Reference Electrode

A two-part reference electrode for measuring impedance in a lithium-ion cell includes a first part (electrode Ref) and a second part (electrode Ref), each of which includes a metallic conductor. The first part and the second part are attached to a substrate separately from each other, and have a substantially constant spacing. The separator of the lithium-ion cell can act as a substrate. The electrode can be used for determining temperature and for detecting degradation of the electrode or electrolyte by way of impedance measurement. The electrode can also be used as a reference electrode for measuring half-cell potentials.