High-rate Ni-rich single-crystal cathodes with highly exposed {0 1 0} active planes through in-situ Zr doping

Abstract

Nickel (Ni)-rich cathodes with high energy density will play a crucial role in the rapidly growing electric vehicles sector. However, the large-scale application of Ni-rich cathodes is still limited by structural instability and severe capacity decay. Even though the construction design of single-crystal cathodes alleviates these defects, the sluggish lithium ion (Li+) diffusion between the larger single-crystal particles restricts its rate performance. We propose an in-situ zirconium (Zr) ion doping strategy to modulate the primary particle morphology of precursors and achieve their corresponding single-crystal cathodes with highly exposed {010} planes. The high percentage of {010} planes will deliver more Li+ diffusion channels and improve the transportation kinetics. Moreover, the homogeneous doping of Zr inside the bulk phase will significantly suppress the anisotropic shrinkage of c-axis and maintain an intact internal structure, thus preventing the accumulation of rock-salt phases. As a result, the Zr-doped single-crystal cathode exhibits excellent cycling stability, whether at 25 ℃ or 45 ℃. More importantly, the rate performance of cathodes has been remarkably enhanced after Zr modification. At the ultra-high rate of 10 C, it can maintain a high specific capacity of 121.4 mAh g−1 (81.8 % of capacity retention) after 250 cycles in the 3.0–4.3 V range.