Extending the energy-power balance of Li-ion batteries using graded electrodes with precise spatial control of local composition
Extending the energy-power balance of Li-ion batteries using graded electrodes with precise spatial control of local composition
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DOI：
10.1016/j.jpowsour.2022.231758
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发表时间：
2022-09
影响因子：
9.2
通讯作者：
Chuan Cheng;R. Drummond;S. Duncan;P. Grant
中科院分区：
文献类型：
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作者：
Chuan Cheng;R. Drummond;S. Duncan;P. Grant
商用锂离子电池电极是由组成材料随机混合而成，30多年来基本没有变化。在快速充放电过程中，电极尺度上的锂离子浓度梯度会随着过电位的空间分布、活性物质的利用和降解而发展，最终限制了可实现的能量-功率组合的范围。我们扩大了能量-功率特性，并降低了电池降解率，使用在微尺度上进行成分分级的电极来均匀化活性物质的利用。通过逐层沉积技术，将梯形梯度组成lifepo4阴极与传统电极进行了比较：在能量密度为500 Wh L−1时，最佳梯度电极设计将功率密度从大约100 W L−1提高到630 W L−1，而在功率密度为300 W L−1时，能量密度从大约420 Wh L−1提高到600 Wh L−1。研究结果强调了新的制造方法和电极设计的潜力，为现有和未来的锂离子电池化学提供性能增强。
Commercial Li-ion cell electrodes comprise a random mix of the constituent materials largely unchanged for more than three decades. During fast charge/discharge, electrode-scale Li-ion concentration gradients develop, along with a spatially heterogeneous distribution of overpotential, utilization and degradation of active material, which ultimately restricts the range of realizable energy-power combinations. We expand energy-power characteristics and reduce cell degradation rate using electrodes that are compositionally graded at the microscale to homogenize active material utilization. Trapezoidal-graded composition LiFePO4cathodes, enabled by a layer-by-layer deposition technique, are compared with conventional electrodes: at an energy density of 500 Wh L−1the best graded electrode design increased power density from approximately 100 W L−1to 630 W L−1, while at a power density of 300 W L−1, the energy density increased from approximately 420 Wh L−1to 600 Wh L−1. The results highlight the potential for new manufacturing approaches and electrode designs to provide performance enhancements for existing and future Li ion battery chemistries.