Abstract:

Ni-rich (Ni≥0.8) oxide cathode materials can satisfy the demands of high energy density and low cobalt for next-generation power batteries due to their large reversible capacity, high compaction density and low cost. The electrochemical performance of Ni-rich cathode materials is directly affected by the size, sphericity, size distribution and sub-nanoplate stacking of the hydroxide precursor, which is commonly produced by the means of co-precipitation method in commercialization. During the synthesis process, the pH, ammonia concentration and feeding rate affect the precipitation rate and the final product quality. The optimization design of the reactor could improve the mixing of the reactants and enhance the heat and mass transfer. Combining with the theoretical calculation of the co-precipitation reaction process parameters, this review summarized the structure design principle of the continuous stirred tank reactor(CSTR) and the influence rule of key synthesis parameters on nucleation growth and microstructure of precursors. Finally, the improvement trend of precursor in the future was prospected by analyzing the current market situations of Ni-rich (Ni≥0.8) oxide cathodes.

Key words: co-precipitation, high energy density, continuous stirred tank reactor, process reinforcement, Ni-rich cathode material

摘要：

高镍氧化物正极材料（Ni质量分数≥0.8）具有高比容量、高压实密度、低成本等优势，能够满足下一代动力电池低钴和高能量密度的需求。其中，氢氧化物前体的尺寸、球形度、粒度分布以及纳米片堆积方式等直接影响最终产品的性能。共沉淀法是目前普遍采用的商业化制备氢氧化物前体的途径。在合成过程中，反应体系溶液的pH、氨水浓度、进料速度等影响产物沉淀速率和产品质量，而反应釜的结构优化有助于提高溶液的混合、热质传递等。本文结合共沉淀反应工艺参数的理论计算，介绍了制备高镍氧化物正极材料前体连续搅拌反应器系统（CSTR）的结构设计原理，总结了合成工艺参数对前体成核生长、微结构的影响规律，介绍了共沉淀法制备优质前体的关键因素。最后，通过分析我国高镍氧化物前体的市场现状，展望了共沉淀法制备前体的未来发展趋势。

关键词: 共沉淀法, 高能量密度, 连续搅拌反应器, 过程强化, 高镍正极材料