High-temperature storage deterioration behaviors of lithium-ion batteries using nickel-rich cathode and SiO–C composite anode

The deterioration behaviors of the lithium-ion pouch full cells consisted of Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and SiO–C composite anode after stored at 55 °C for 7 days were investigated. A significant increase in the interface impedance of the cell and a change in structure of the anode surface passivation films are attributed to constant electrolyte decomposition inducing the regeneration of SEI films, which result in the constant consumption of active lithium source and rapid capacity fading. After high-temperature storage, the initial charge capacity of anode is reduced from 609.1 to 514.3 mAh g−1. Furthermore, the disintegration of NCM811 cathode secondary particle was observed, and after high-temperature storage, the reversible capacity of cathode decreases from 170.6 to 134.9 mAh g−1.