Improving Li+ Kinetics and Structural Stability of Nickel-Rich Layered Cathodes by Heterogeneous Inactive-Al3+ Doping

Abstract

To improve the Li+ kinetics and structural stability of high-capacity nickel-rich layered oxides, but not at the cost of reducing reversible capacity, a heterogeneous inactive-Al3+ doping strategy is proposed to build an Al3+-rich surface within a low doping amount. As anticipated, the heterogeneous inactive-Al3+ doped nickel-rich LiNi0.7Co0.15Mn0.15O2 shows a large reversible capacity of ∼215 mAh g–1, corresponding to a high energy density of ∼850 Wh kg–1. Moreover, it also exhibits long-term cycle lifespan, capacity retention of ∼90% after 200 cycles even at a high upper cutoff voltage of 4.5 V (vs Li/Li+), and improved thermal stability. Surprisingly, the heterogeneous inactive-Al3+ doped electrode shows a high capacity of ∼145 mAh g–1 even at a high rate of 10C, which corresponds to ∼70% capacity retention at 0.1C, due to the enhanced Li+ kinetics. Also this heterogeneous inactive-ion doped approach is capable of being readily expanded to other types of layered, spinel and olivine cathodes to enhance ...