A thermodynamic method is proposed that can determine to which electrode the entropy evolution is attributable without destroying the lithium battery. The entropy evolution of two battery types sharing the same anode composition but different cathode compositions are monitored over cycling. Then, the entropy evolution of the two types are cross-correlated to identify their common component. From the correlation coefficient, the electrode that dominates the entropy evolution at each SOC could be identified. Indicating that the material evolution of each electrode in a battery could be monitored separately by the thermodynamic analysis. Moreover, in combination with prior nondestructive tools, the identification of each electrode's contribution to the total cell entropy opens the possibility to nondestructively monitor the degradation processes of each electrode continuously during the battery cycling.