A Versatile Reference Electrode for Lithium Ion Battery Use

A lithium-ion battery reference electrode applicable to both laboratory and onboard vehicle use provides a high level of understanding of electrochemical processes within a cell and enables highly sophisticated, real-time electrode control that maximizes cell utilization, life, safety, and overall value. The approach taken for this work is to combine the chemical stability of LFP with miniaturization in the form of an extremely thin and porous active layer, and optimal placement within the cell by coating the active reference layer on an additional layer or separator that is inserted between the anode and cathode in the cell. This thin, porous, separator-mounted reference has no effect on the cell beyond that of an extra layer of separator. Extraction of electrode kinetic parameters and electrode-level control of DC fast charge are shown for NCMA/Graphite cells in two different formats to demonstrate the simplicity, fidelity, and robustness of the reference electrode design. © 2025 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.