Correlating the influence of porosity, tortuosity, and mass loading on the energy density of LiNi0.6Mn0.2Co0.2O2 cathodes under extreme fast charging (XFC) conditions

JOURNAL OF POWER SOURCES

卷:474

Article

Parikh, Dhrupad^1,2  Christensen, Tommiejean³  Li, Jianlin^1,2 

[1] Oak Ridge Natl Lab, Transportat Sci Div, Oak Ridge, TN 37831 USA

[2] Univ Tennessee, Bredesen Ctr Interdisciplinary Res & Grad Educ, Knoxville, TN 37996 USA

[3] Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA

关键词: Extreme fast charging (XFC);    Porosity;    Tortuosity;    Gravimetric energy density;    LiMn0.6Mn0.2Co0.2O2;    Diffusion length;    Symmetric cells;    Li metal plating;   

DOI  :  10.1016/j.jpowsour.2020.228601

来源: Elsevier

【 摘 要 】

Extreme fast charging capabilities along with high energy density of Li-ion batteries are the key factors to increase the adoption of electric vehicles while eliminating the problem of range anxiety. The U.S Department of Energy has a goal of <12 min charging time with energy density of >200 Wh kg(-1). A combined improvement in the electrode architecture, electrolyte properties, and separator membrane is necessary to achieve this goal. Cells with thin electrodes are capable of extreme fast charging at the expense of low energy density and high cost. Electrode engineering can maximize energy density. Here, the influence of porosity, mass loading and charging protocols on capacity and energy density and electrode kinetics are investigated under extreme fast charging conditions. Increasing the mass loading from 11.5 mg cm(-2) to 25 mg cm(-2) compromises the rate performance due to the mass transport limitation and underutilization of thick electrodes. Reducing the electrode porosity from 50% to 35% improves the rate performance ascribed to shorter Li ion diffusion length. Symmetric cells are cycled to verify the performance of the half cells, suggesting that Li metal plating is the rate limiting step under high current density.

【 授权许可】

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