Probing the improved stability for high nickel cathode via dual-element modification in lithium-ion

Abstract

One of the major hurdles of nickel-rich cathode materials for lithium-ion batteries is the low cycling stability, especially at high temperature and high voltage, originating from severe structural degradation, which makes this class of cathode less practical. Herein, we compared the effect of single and dual ions on electrochemical performance of high nickel (LiNi0.88Mn0.03Co0.09O2, NMC) cathode material in different temperatures and voltage ranges. The addition of a few amounts of tantalum (0.2 wt%) and boron (0.05 wt%) lead to improved electrochemical performance. The co-modified LiNi0.88Mn0.03Co0.09O2 displays an initial discharge capacity of 234.9 mAh/g at 0.1 C and retained 208 mAh/g at 1 C after 100 cycles at 45 °C, which corresponds to a capacity retention of 88.5%, compared to the initial discharge capacity of 234.1 mAh/g and retained capacity of 200.5 mAh/g (85.6%). The enhanced capacity retention is attributed to the synergetic effect of foreign elements by acting as a surface structural stabilizer without sacrificing specific capacity.