The use of a single-crystal nickel-rich layered NCM cathode for excellent cycle performance of lithium-ion batteries

Abstract

With the continuous development and progress of new energy electric vehicles, high-capacity nickel-rich layered oxides are widely used in lithium-ion battery cathode materials, and their cycle performance and safety performance have also attracted more and more attention. In this experiment, a single crystal LiNi_0.83Co_0.12Mn_0.05O₂ cathode material was synthesized by co-precipitation and high-temperature solid-phase methods, and its crystal structure, morphology, composition, element distribution and electrochemical performance were systematically studied. The results show that the synthesized single crystal particles have good morphology, uniform element distribution, low Li⁺/Ni²⁺ ion mixing degree, and well-developed layered structure. Under the test conditions of 25 °C and 2.75–4.30 V, the first discharge specific capacity of a button cell at 0.1C(1C = 210 mA g⁻¹) reaches 209.7 mA h g⁻¹, the coulomb efficiency is 91.19%, and the capacity retention is 100.90% after 100 cycles at a rate of 0.2C. It should be noted that the capacity retention of the soft package battery is 88.72% after 500 cycles at a rate of 0.3C. Such excellent performance may be because, compared with polycrystalline materials, the smooth micron-sized single crystal particles effectively reduce the electrode/electrolyte interface reaction, volume change and irreversible phase change caused by charging and discharging.