TY - JOUR
T1 - Understanding the mechanism of capacity increase during early cycling of commercial NMC/graphite lithium-ion batteries
AU - Guo, Jia
AU - Li, Yaqi
AU - Pedersen, Kjeld
AU - Gurevich, Leonid
AU - Stroe, Daniel-Ioan
PY - 2022/11
Y1 - 2022/11
N2 - A capacity increase is often observed in the early stage of Li-ion battery cycling. This study explores the phenomena involved in the capacity increase from the full cell, electrodes, and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell. The results show an increase of 1% initial capacity for the battery aged at 100% depth of discharge (DOD) and 45 °C. Furthermore, large DODs or high temperatures accelerate the capacity increase. From the incremental capacity and differential voltage (IC-DV) analysis, we concluded that the increased capacity in a full cell originates from the graphite anode. Furthermore, graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs, thus in agreement with the full cell results. Post-mortem analysis results show that a larger DOD enlarges the graphite d-space and separates the graphite layer structure, facilitating the Li+ diffusion, hence increasing the battery capacity.
AB - A capacity increase is often observed in the early stage of Li-ion battery cycling. This study explores the phenomena involved in the capacity increase from the full cell, electrodes, and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell. The results show an increase of 1% initial capacity for the battery aged at 100% depth of discharge (DOD) and 45 °C. Furthermore, large DODs or high temperatures accelerate the capacity increase. From the incremental capacity and differential voltage (IC-DV) analysis, we concluded that the increased capacity in a full cell originates from the graphite anode. Furthermore, graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs, thus in agreement with the full cell results. Post-mortem analysis results show that a larger DOD enlarges the graphite d-space and separates the graphite layer structure, facilitating the Li+ diffusion, hence increasing the battery capacity.
KW - Capacity increasing
KW - Lithium-ion battery
KW - Full cell
KW - Coin cell
KW - Graphite anode
UR - https://www.sciencedirect.com/science/article/pii/S2095495622003655?via%3Dihub
U2 - 10.1016/j.jechem.2022.07.005
DO - 10.1016/j.jechem.2022.07.005
M3 - Journal article
SN - 2095-4956
VL - 74
SP - 34
EP - 44
JO - Journal of Energy Chemistry
JF - Journal of Energy Chemistry
ER -