Crystal growth kinetics of single-crystal Ni-rich layered cathodes for high-energy lithium-ion batteries
(1. School of Physics and Technology, University of Jinan, Jinan 250022, China;
2. Research Institute of Smart Energy, Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong 999077, China)
2. Research Institute of Smart Energy, Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong 999077, China)
Abstract: The effects of synthesis conditions, especially the heating rate, on the reaction kinetics of Ni-rich cathodes were systematically studied. The growth rate of Ni-rich oxide increases continuously as the heating rate increases. Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations, indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction. The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics. However, the excessively high heating rate aggravates the Li+/Ni2+ mixing in the Ni-rich cathode. The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.
Key words: lithium-ion battery; Ni-rich cathode; single crystal; growth kinetics; heating rate