Irreparable Interphase Chemistry Degradation Induced by Temperature Pulse in Lithium-Ion Batteries

While it is widely recognized that the operating temperature significantly affects the energy density and cycle life of lithium-ion batteries, the consequence of electrode-electrolyte interphase chemistry to sudden environmental temperature changes remains inadequately understood. Here, we systematically investigate the effects of a temperature pulse (T pulse) on the electrochemical performance of LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch full cells. By utilizing advanced characterization tools, such as time-of-flight secondary-ion mass spectrometry, we reveal that the T pulse can lead to an irreversible degradation of cathode-electrolyte interphase chemistry and architecture. Despite negligible immediate impacts on the solid-electrolyte interphase (SEI) on graphite anode, aggregated cathode-to-anode chemical crossover gradually degrades the SEI by catalyzing electrolyte reduction decomposition and inducing metallic dead Li formation because of insufficient cathode passivation after the T pulse. Consequently, pouch cells subjected to the T pulse show an inferior cycle stability to those free of the T pulse. This work unveils the effects of sudden temperature changes on the interphase chemistry and cell performance, emphasizing the importance of a proper temperature management in assessing performance. A sudden operating temperature change (T pulse) results in a faster capacity fade of graphite|LiNi0.8Mn0.1Co0.1O2 (Gr|NMC811) pouch full cells. Comprehensive post-mortem analyses unveil that the T pulse mainly causes a deterioration of cathode-electrolyte interphase architecture and chemistry, which in turn accelerates anode-electrolyte interphase degradation due to aggregated chemical crossover from the cathode during long-term cycling.image