Insight into the Role of Co and Mn Elements in Ni-Rich LiNi_0.9Co_xMn_0.08–xAl_0.02O₂ Cathode Materials

Abstract

Ni x Co y Mn z Al 1−x−y−z O 2 (NCMA, 1 − x − y − z ≥ 0.9) is one of the most promising cathode materials for lithium-ion batteries due to its high energy density and low cost. However, the roles of Co and Mn contents in NCMAs remain to be investigated. Herein, LiNi 0.9 Co x Mn 0.08−x Al 0.02 O 2 (x = 0.07, 0.05, 0.03) are synthesized by a hydroxide coprecipitation method and high-temperature solidphase method. The results show that Co can increase the value of the c-axis, decrease the content of Ni 2+ on the surface, and inhibit lattice expansion along the c-axis in the voltage range of 2.7−4.3 V. However, Mn has a superiority in reducing the primary particle size and preventing the sharp collapse of the lattice along the c-axis in the deep delithiated state, corresponding to a voltage range of 4.3− 4.5 V. These new insights are intended to guide further research on NCMAs.

Damage mechanisms and recent research advances in Ni‐rich layered cathode materials for lithium‐ion batteries

“…Manganese shows a relatively persistent þ4 valence state when the nickel level is significantly higher than the manganese content (Figure 1E). 19 Zeng et al 35 investigated the mechanism of Co and Mn elements in high nickel materials. They found that the Co element can increase the Li layer spacing, enhance the migration rate of lithium ions to achieve excellent multiplicity performance, and inhibit the rapid expansion of the lattice along the c-axis during charging.…”

“…Manganese shows a relatively persistent +4 valence state when the nickel level is significantly higher than the manganese content (Figure 1E). 19 Zeng et al 35 . investigated the mechanism of Co and Mn elements in high nickel materials.…”