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| Preparation of Ultra-High Nickel Ternary Precursor by Pre-seeded Co-precipitation Process |
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Received:March 12, 2025
Published Online:May 30, 2025
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| DOI：10.20237/j.issn.1007-7545.2025.06.020 |
| KeyWord:pre-seeded co-precipitation method; ultra-high nickel; ternary precursor; pH; temperature; total organic carbon (TOC) |
| Author | Institution |
| GAO Ce |
中冶瑞木新能源科技有限公司，河北 唐山 |
| ZHANG Suliang |
中冶瑞木新能源科技有限公司，河北 唐山 |
| YANG Yang |
中冶瑞木新能源科技有限公司，河北 唐山 |
| GU Haitao |
中冶瑞木新能源科技有限公司，河北 唐山 |
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| Abstract: |
| In recent years, with changes in the global energy landscape, electric vehicles (EVs) powered by renewable energy sources have undergone significant development. Batteries serve as the heart of EVs, dictating their power and range performance. Ternary lithium-ion batteries, boasting high energy density and voltage platforms, have emerged as the preferred choice for long-range EVs. The cathode material represents the core component of ternary lithium-ion batteries, determining key properties such as energy density, cycle performance, and rate capability. The capacity of ternary cathode materials is primarily contributed by nickel, with higher nickel content correlating to greater capacity. To meet growing demands for extended EV ranges, ternary cathode materials have progressively trended toward high-nickel and ultra-high-nickel compositions. Ternary precursors, the foundational materials for cathode production, influence critical attributes like morphology, particle size distribution, specific surface area, and crystallinity of the final cathode. Therefore, developing high-performance ternary precursors is essential for manufacturing advanced ternary materials.The preparation of ternary precursors mainly involves continuous and batch processes. Among these, the continuous method has become the commercial production standard due to its simplicity and ease of operation. This study develops a novel ternary precursor synthesis approach, i.e., the pre-seeded co-precipitation process. This technique first generates small-sized precursor seeds in a dedicated seed reactor. Meanwhile, growth reactor conditions are adjusted to suppress spontaneous nucleation. The pre-prepared seeds are then introduced into a separate growth reactor for secondary growth. By deriving controlled-size and quantity "nuclei" from the seed reactor, this method significantly reduces synthetic instability. Compared to traditional continuous processes, precursors produced via the pre-seeded co-precipitation process exhibit superior sphericity, reduced agglomeration, and narrower particle size distributions.Using this method, an ultra-high-nickel ternary precursor, Ni?.??Co?.??Mn?.??(OH)?, was synthesized. A single-factor comparison approach was employed to investigate the effects of process parameters such as pH value, temperature, and total organic carbon (TOC) concentration on precursor crystallinity, specific surface area, and tap density. The results show that within a pH range of 10.6–10.8, increasing pH value lead to thinning of primary particles. At pH value of 10.9, both lateral and radial grain sizes are decreased, with primary particles transitioning from plate-like to needle-like structures, indicating pH value as a critical morphological determinant. Additionally, the full width at half maximum (FWHM) of the (001) diffraction peak initially decreases before increasing with rising pH value, suggesting an initial enhancement followed by degradation of crystallinity, and the optimized crystallinity can be obtained at pH value of 10.7. Temperature primarily influences reaction kinetics. Lower temperatures transform primary particles from plate-like to fine needle-like structures, concurrently increasing specific surface area. Higher temperatures enhance reaction activity, promoting ordered particle stacking and improving crystallinity, with 75 °C identified as the optimal temperature. TOC concentration studies reveal that increasing organic content thin primary particles and enlarge specific surface area. Low TOC conditions produce dense, radially structured particles, while high TOC (≥216 mg/L) induces porosity and Na2SO? impurity formation, severely disrupting crystallinity. Thus, TOC control below 46 mg/L is deemed critical for high-quality precursors.Under optimized conditions (pH 10.70, 75 °C, TOC 35 mg/L), the pre-seeded co-precipitation process yields Ni?.??Co?.??Mn?.??(OH)?. After sintering with lithium carbonate and assembling into coin cells, electrochemical tests demonstrate a median voltage of 3.75 V, discharge capacity of 210.8 mAh/g, 89.4% initial efficiency, and 96.8% capacity retention after 50 cycles under 0.2C (2.8–4.3 V) conditions, confirming excellent electrochemical performance. |
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