Diagnostic of the failure mechanism in NiSb2 electrode for Li battery through analysis of its polarization on galvanostatic cycling

A simple analysis of the polarization resistance of the electrodes as function of the loading mass for various cycling rates allows identifying the fading mechanism on cycling of NiSb2, a typical conversion material: pulverization of active mass and further degradation of the electronic wiring at high rate and agglomeration of the active mass at low rate. Such rate-control of the degradation mechanism might reflect a thermodynamic instability of interfaces in the lithiated compound, which would however be in kinetic competition with the Lithium de-insertion. The analysis of the electrode polarization resistance fingerprint to rapidly identify the failure mechanism in a composite electrode can be generalized to other active materials.

► Development of an efficient and simple methodology allowing identifying the fading mechanism on cycling of electrodes for Li batteries. ► The degradation mechanism is rate dependant and reflects a thermodynamic instability of interfaces in the lithiated compound. ► This analyze of the electrode fingerprint may be generalized to numerous electrode materials.