Degradation identification of individual components in the LiyNi1/3Co1/3Mn1/3O2-LiyMn2O4 blended cathode for large format lithium ion battery

The degradation behaviors of individual components in the LiyNi1/3Co1/3Mn1/3O2(NCM)-LiyMn2O4(LMO) blended cathode are investigated in this paper. A prognostic/mechanistic model is applied to quantitatively analyze the capacity fading mechanism of the lithium ion battery with blended cathode. NCM and LMO are considered to be connected in parallel with a same potential during cycling. Current is distributed between NCM and LMO based on the dQ/dV curves, and the capacities of NCM and LMO can thus be quantitatively identified, respectively. The identified model parameters show that both NCM and LMO suffer loss of active material (LAM), but NCM degrades faster than LMO. Loss of lithium inventory also contributes to the capacity degradation, whereas anode shows little LAM until 330 cycles. The identified capacity degradation mechanism is validated by the coin cells test data, as the capacity degradation of the coin cells assembled with the aged electrodes compared with those made of fresh electrodes are consistent with the identified results. (C) 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.