Capacity fade of LiAlyNi1-x-yCoxO2 cathode for lithium-ion batteries during accelerated calendar and cycle life tests (surface analysis of LiAlyNi1-x-yCoxO2 cathode after cycle tests in restricted depth of discharge ranges)

Cycle performance of a LiAl0.10Ni0.76Co0.14O2 (NCA) cathode/graphite cell closely depended on the range of depth of discharge in charge–discharge processes (ΔDOD). When ΔDOD was 10–70%, cycle performance at 25 °C was maintained even at 60 °C. Deterioration phenomena were analyzed by electrochemical method, X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), and micro-cracks in NCA particles were analyzed with cross-sectional views by scanning electron microscopy (SEM). Many micro-cracks were observed only after a 0–100% DOD region cycle test.