A conductive agent, which is typically added to overcome the low electronic conductivity of Ni-rich-layered oxides, plays a significant role toward performance improvement of layered-oxide-based cathodes. Herein, the effects of the specific surface area, powder density, and aggregation characteristics of a conductive agent on Li_1.03Ni_0.88Co_0.08Mn_0.04O₂ (Ni-rich NCM) cathode performance are studied. The aggregation of conductive agents is disadvantageous for the distribution/arrangement of active materials and leads to polarization on the electrode surface. The specific surface area, which is proportional to porosity, contributes to the acceleration of electrode kinetics. However, the application of high pressure that makes a conductive agent excessively dense can degrade kinetic performance in the electrode. The low powder density of a conductive agent results in a nonhomogeneous electrode morphology and inhibits the mobility of Li ions in the electrolyte because of the segregation of the active materials from conductive agents. Powder density has a dominant effect on electrochemical performance. Even if the same active material is used, cycle retention is improved by 15%. In conclusion, the larger the specific surface area, the lower the powder density. Moreover, the less well-aggregated the conductive agent, the higher the performance of the Ni-rich NCM cathodes.

中文翻译：

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通过控制富镍正极中导电剂的性能来提高能量密度

通常添加导电剂以克服富镍层状氧化物的低电子电导率，对层状氧化物基阴极的性能改进起着重要作用。在此，导电剂的比表面积、粉体密度和聚集特性对Li _1.03 Ni _0.88 Co _0.08 Mn _0.04 O _2的影响研究了（富Ni NCM）正极性能。导电剂的聚集不利于活性材料的分布/排列，并导致电极表面极化。与孔隙率成比例的比表面积有助于电极动力学的加速。然而，使导电剂过度致密的高压的施加会降低电极的动力学性能。导电剂的低粉末密度导致电极形态不均匀，并且由于活性材料与导电剂的分离，抑制了锂离子在电解质中的迁移率。粉末密度对电化学性能具有主要影响。即使使用相同的活性材料，循环保持率也提高了 15%。综上所述，比表面积越大，粉末密度越低。此外，导电剂聚集得越少，富镍 NCM 正极的性能就越高。