Multiscale strain alleviation of Ni-rich cathode guided by in situ environmental transmission electron microscopy during the solid-state synthesis

Fundamentals, status and challenges of direct recycling technologies for lithium ion batteries

“…Zhang et al achieved real-time nanoscale characterization of the synthesis process of NCM811 by using in situ environmental transmission electron microscopy (ETEM). 289 By directly heating the precursor without adding lithium salt, they observed distinct cracks along the primary grain boundaries caused by thermal decomposition. However, upon adding the lithium source, the overall particle shape irregularly shrank due to uneven stress resulting from thermal decomposition and lithiation reaction.…”

High-Capacity LiNi0.8Co0.1Mn0.1O2 Positive-Electrodes in the Nearly Saturated and Fluorinated Acetate-Diluted Electrolyte Solutions

“…72%. , If more lithium ions are extracted from NCM in a charge process to increase the discharge capacity, it ends up decreasing the capacity in subsequent cycles due to the degradation of the NCM electrodes. The deterioration mechanisms proposed so far − are the irreversible transition of crystal structure from layered-rock-salt to spinel and rock-salt, − O 2 gas release, − dissolution of transition metal ions, − granular cracks, − and unfavorable precipitation of electrolyte decomposition products. − These phenomena occurred at and near the surface of NCM particles, and hence the electrolyte solution should also be involved in the above irreversible phenomena of NCM. To be more specific, charging of NCM positive-electrodes increases their oxidation power and makes the electrolyte solutions more vulnerable to oxidation.…”