Extreme Fast Charging of High Energy Density Lithium Ion Battery

Abstract

The demand for high-energy-density batteries using Ni-rich cathodes is increasing due to the continuous expansion of the electric vehicle (EV) market. U.S. Department of Energy has stated the need for extreme-fast-charging (XFC) batteries that achieve an 80% state of charge (SOC) in less than 15 min. However, Ni-rich cathodes tend to lose capacity quickly under XFC conditions, which compromises their structural integrity. In addition, XFC conditions rapidly generate significant heat due to the high current applied to the cell, leading to the degradation of cell components. It is challenging to create Ni-rich cathodes that can withstand XFC conditions while still maintaining maximum energy density and long-term cycling performance. In this study, a cathode called Li[Ni0.92Co0.06Al0.01Nb0.01]O2 (Nb-NCA93) is introduced, which has a high energy density of 869 Wh kg-1. The presence of Nb in the cathode induces grain refinement in its secondary particles, reducing internal stress and preventing heterogeneity of Li concentration during cycling. When used in a full-cell, the Nb-NCA93 cathode reaches full charge within 12 minutes and retains 85.3% of its initial capacity after 1000 cycles, cycled at full depth of discharge. Furthermore, the refined microstructure of the Nb-NCA93 cathode limits heat generation under XFC conditions. References H.-H. Ryu, K.-J. Park, C. S. Yoon, Y.-K. Sun, Chem. Mater. 2018, 30, 1155 C. S. Yoon, H.-H. Ryu, G.-T. Park, J.-H Kim, K.-H. Kim, Y.-K Sun, J. Mater. Chem. A 2018, 6, 4126 U.-H. Kim, H.-H. Ryu, J.-H. Kim, R. Mücke, P. Kaghazchi, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater. 2019, 9, 1803902