High-entropy Doping Modification of High-nickel Single-crystal Layered Ternary Cathode Material

LiNi x Co y Mn1- x - y O2 (NCM, x≥0.8), a promising cathode material for lithium-ion batteries, possesses high energy density and excellent discharge performance. However, it also appears drawbacks such as severe cation disorder, poor cycling performance and insecurity at high temperatures and high cut-off voltages. In this study, a high-entropy (HE) doping modification strategy was introduced into a high-nickel and low-cobalt LiNi0.86Co0.04Mn0.1O2 cathode material, and a high-nickel single-crystal layered ternary cathode material was synthesized by a high-temperature solid-state reaction method. The results show that at 0.1C (1C=180 mA·g-1) and 25 ℃, the battery equipped with modified material has a reversible discharge capacity of 197 mAh·g-1 and exhibits excellent discharge performance at high temperatures and high cut-off voltages. At 0.5C, 55 ℃ and 4.3 V, the discharge capacity reaches 281 mAh·g-1, while at 0.5 C, 25 ℃ and 4.5 V, the discharge capacity is as high as 194 mAh·g -1. This material has a good layered structure with a uniform arrangement of nanoscale primary particles at microscale and a smaller total impedance. This work significantly improves cycling performance and safety of high-nickel ternary cathode materials at high temperatures and high cut-off voltages, providing a good modification method for the cobalt-free, high-nickel and practical application of ternary materials.