Probing Sources of Capacity Fade in LiNi₀.₆Mn₀.₂Co₀.₂O₂ (NMC622): An Operando XRD Study of Li/NMC622 Batteries during Extended Cycling

摘要: LiNi₀.₆Mn₀.₂Co₀.₂O₂ (NMC622) is one of the most promising Li-ion battery cathodes as it delivers high capacity at potentials. However, potentials also lead to decreases in retention where disintegration secondary particles has been implicated a major driving force this fade. This attributed anisotropic lattice changes and increased microstrain during cycling. To probe how these factors affect fade, Li/NMC622 batteries were cycled from 3 4.3 or 4.7 V probed with operando X-ray diffraction (XRD) over 1st, 2nd, 101st cycles. Further characterization scanning electron microscopy inductively coupled plasma-optical emission spectroscopy was performed. The use XRD many cycles allowed for collection detailed structural information real time frame which fading can be observed. During first two cycles, cells charged exhibit compared V. Upon cycle, when significant fade observed, show identical another, while charge limit induces more microstrain. shows that elevated limits driver particle NMC622 cathodes. study provides important insights into mechanisms NMC/Li-ion batteries, will enable design NMC electrodes deliver both higher capacities better retention.