Exploring the Influence of Temperature on Anode Degradation in Cycling-Aged Commercial Cylindrical Graphite-Si|NCA Cells

Abstract

The degradation mechanisms of commercial graphite–SiOx/NCA battery related to the aging process in full cell under cycling conditions at three different temperatures, namely, 10 °C, 25 °C, and 45 °C, have been studied via post-mortem analysis, emphasizing the high energy density graphite–SiOx anode behaviour. The aging process of the full battery has been studied by non-destructive electrochemical methods. Then, to gain more understanding on the mechanisms that govern the graphite–SiOx degradation, full cells are disassembled, and the anodes are studied by physicochemical analysis techniques, electron microscopy techniques, and electrochemical characterizations. The battery cycled at 25 °C, between 2.5 and 4.2 V, shows higher cyclability than those cycled at 45 °C and 10 °C, at SoH 80%. Under these conditions, the structural and morphological changes undergo by graphite–SiOx and SiOx particles, respectively, and the loss of active material, together with the SEI growth explain the anode degradation.