Resolving high potential structural deterioration in Ni-rich layered cathode materials for lithium-ion batteries operando

Ageing of High Energy Density Automotive Li-ion Batteries: The Effect of Temperature and State-of-Charge

“…From ex situ studies, it is seen that high-temperature cycling affects the loss of active material more significantly [11]. The study of oxygen evolution on materials extracted from the same BoL cell has been conducted previously by our group, showing CO2 evolution as a result of reactions involving lattice oxygen and electrolyte [46]. The cells cycled between 50-100% SoC and 0-100% SoC have shown the presence of voids in larger particles (Figure 9 and SI Table S 2).…”

“…However, the cross-section study does not provide sufficient statistics on whether it is present for the entire sample due to the technique limitation. Our previous study conducted on BoL samples has also showed visible upon material delithiation yet reversible upon relithiation cracking [46].…”

“…The results of the XRD analysis indicate that there is a minor shift in the c lattice parameter in the studied samples, with an EoL maximum deviation of 0.2% from the BoL sample. This deviation is significant, considering that the c parameter usually deviates by approximately 1% during a delithiation within the stability region (up to 4.18 V full cell potential) [46]. Notably, all cells cycled to high state of charge (R50-100, R0-100, H50-100, H0-100) have the same lattice parameter deviation at the same temperatures.…”

“…Cross section sample preparation of electrodes were done using ion polishing. The methodology is further described in our previous study [46].…”

“…One disk ∅ 10 mm for positive electrode and two disks ∅ 20 mm for negative electrode were used per sample. The followed detailed methodology for further sample preparation can be accessed in our previous study [46].…”