Design of workflows for cross-talk detection and lifetime deviation onset in Li-ion batteries

Developing advanced electrolytes or electrode materials for Li-ion batteries heavily relies on the use of performance metrics, among which capacity retention and coulombic efficiency remains the gold standards. While powerful at predicting initial degradation rates, these metrics fall short to predict knee points that can abruptly lead to the sudden death of battery cells. Indeed, knee points often originate from complex interplays between electrodes, through a cascade of parasitic reactions or modification of cell balancing. In this work, we analyze and demonstrate how combining adequate electrochemical testing protocols, coupled with analysis such as differential voltage analysis or capacity marching analysis, allows disentangling effects as complex as cross talking events for selected graphite/Ni-rich cell chemistries. We believe that, using this set of workflows, comprehensive analysis of capacity retention curves can be accurately carried out, and should become the new standard for screening novel electrolytes and materials for high performance battery chemistries.