Low‐Temperature Synthesis of Single‐Crystal LiNi 0.93 Co 0.05 Mn 0.02 O 2 Cathode With a Stable Structure Achieved by Sr/Zr Co‐Modification

ABSTRACT Compared to polycrystalline cathode materials, single‐crystal materials demonstrate superior mechanical strength and structural stability. However, as the Ni content increases in LiNi x Co y Mn z O 2 (NCM, x + y + z = 1) cathode materials, the corresponding defects within the crystal also rise, considerably threatening the performance of the cathode material. Relying solely on single‐crystallization to curb structural degradation has proven insufficient. Furthermore, conventional single‐crystal synthesis typically requires high‐temperature sintering (> 800°C), which not only drastically increases energy consumption but also exacerbates cation mixing. Here, we propose a refined fabrication method for preparing single‐crystal Ni‐rich cathode materials by introducing trace amounts of Sr and Zr sources during the sintering process, we successfully synthesized single‐crystal LiNi 0.93 Co 0.05 Mn 0.02 O 2 cathode material (NCM‐SrZr) at 740°C. Sr primarily functions as a fluxing agent, lowering the temperature required for single‐crystal morphology formation. The introduction of Zr is mainly aimed at leveraging its oxygen fixation capability to stabilize the lattice framework. The prepared NCM‐SrZr exhibits excellent electrochemical behavior. After 200 cycles at 1 C, it maintains a high‐capacity retention rate of 93% and still delivers an outstanding specific capacity of 167 mAh·g −1 even at a high rate of 10 C. Notably, it maintains a capacity retention rate at least 94% even under harsh testing conditions, such as after 100 cycles at 5 C or at 60°C. The Sr/Zr dual‐element doping optimization strategy adopted in this study features a simple process, low energy consumption, and substantial performance enhancement, offering an economical and effective route for constructing ultrahigh‐nickel single‐crystal cathodes with reinforced structural stability.