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

Abstract

The degradation mechanisms of commercial graphite–SiO x /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–SiO x 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–SiO x 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–SiO x and SiO x particles, respectively, and the loss of active material, together with the SEI growth explain the anode degradation.