A Mathematical Model for Intercalation Electrode Behavior I. Effect of Particle‐Size Distribution on Discharge Capacity
A Mathematical Model for Intercalation Electrode Behavior I. Effect of Particle‐Size Distribution on Discharge Capacity
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DOI：
10.1149/1.1838344
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发表时间：
1998-03
影响因子：
3.9
通讯作者：
G. Nagarajan;J. W. Zee;R. Spotnitz
中科院分区：
文献类型：
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作者：
G. Nagarajan;J. W. Zee;R. Spotnitz
建立了一个数学模型，研究了粒径分布对锂/隔膜/嵌入电极系统恒电流放电行为的影响。最近开发的包装理论已被纳入第一原理模型的嵌入电极提供了一个合理的基础，包括PSD上的堆积密度的影响。该模型被用来调查如何二元混合物的球形颗粒影响电极容量。插入电极的电极容量针对包括所施加的电流密度、电极的厚度以及颗粒的体积分数、尺寸和尺寸比的各种参数来计算。该模型表明，由两种不同尺寸的颗粒组成的电极可以具有比由单一尺寸的颗粒组成的电极显著更高的容量。然而，增加粘着密度增加了液相扩散阻力。作为填充密度和液相扩散阻力之间的折衷的结果，放电容量可以通过调节颗粒尺寸、大颗粒和小颗粒的体积分数以及尺寸比来优化。由两种不同尺寸颗粒组成的嵌入电极的脉冲放电显示出与具有单一尺寸颗粒的电极的瞬态行为的显著差异。由于有许多参数控制电极的性能，使用该模型将大大有助于制造上级电极。
A mathematical model is presented to study the effect of the particle size distribution (PSD) on the galvanostatic discharge behavior of the lithium/separator/intercalation electrode system. A recently developed packing theory has been incorporated into a first-principles model of an intercalation electrode to provide a rational basis for including the effect of PSD on packing density. The model is used to investigate how binary mixtures of spherical particles affect electrode capacity. The electrode capacity of an insertion electrode is calculated for various parameters including applied current density, thickness of the electrode, and volume fraction, size, and size ratio of the particles. The model shows that an electrode comprised of two different sized particles can have a significantly higher capacity than an electrode consisting of single-sized particles. However, increasing the tacking density increases the liquid-phase diffusion resistance. As a result of the trade-off between packing density and liquid-phase diffusion resistance, discharge capacity can be optimized by adjusting the particle size, volume fraction of large and small particles, and the size ratio. Pulse discharge of an intercalation electrode comprised of two different sized particles shows a marked difference in transient behavior from that of an electrode which has single-sized particles. Since there are many parameters which control the performance of the electrode, use of this model should aid greatly in making superior electrodes.