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

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-Al 3+ doping strategy is proposed to build an Al 3+ -rich surface within a low doping amount. As anticipated, the heterogeneous inactive-Al 3+ doped nickel-rich LiNi 0.7 Co 0.15 Mn 0.15 O 2 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-Al 3+ 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 their structural stability and Li + kinetics.