Dynamic interplay between phase transformation instabilities and reaction heterogeneities in particulate intercalation electrodes
Dynamic interplay between phase transformation instabilities and reaction heterogeneities in particulate intercalation electrodes
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DOI：
10.1016/j.xcrp.2022.100854
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发表时间：
2021-10
影响因子：
8.9
通讯作者：
Shubham Agrawal;P. Bai
中科院分区：
文献类型：
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作者：
Shubham Agrawal;P. Bai
锂离子电池依靠颗粒状多孔电极来实现高性能，特别是快速充电能力。为了最大限度地减少可能导致局部热点的粒子反应不均匀性，在中尺度上对这些电极（即数百个粒子）进行更深入的了解已成为迫切需要。研究表明，表面上看似随机的反应非均相性实际上是由非平衡材料热力学和外部电化学驱动力之间的相互作用控制的。我们的实验证实了单个粒子周围的真实工作电流密度远高于全局平均电流密度，可以改变相变行为。结合理论和实验分析表明，不同于其他相变多孔电极，并不是所有的相分离过程中，石墨可以抑制在高电流，由于浓度依赖性的交换电流密度的特性。这些见解强调了将材料热力学纳入电化学模型的必要性，以确保对实际多孔电极的自洽理解，从而实现精确的设计和管理。
Lithium-ion batteries rely on particulate porous electrodes to realize high performance, especially the fast-charging capability. To minimize the particle-wise reaction heterogeneities that may lead to local hot spots, deeper understandings of these electrodes at the mesoscale, i.e. hundreds of particles, have become an urgent need. This study reveals that the seemingly random reaction heterogeneities are actually controlled by the interplay between the non-equilibrium material thermodynamics and the external electrochemical driving force. Our operando experiments confirm the true working current density around a single particle that is much higher than the globally averaged current density, can change the behavior of phase transformation. The combined theoretical and experimental analyses reveal that unlike other phase-transforming porous electrodes, not all phase separation processes in graphite can be suppressed at high currents, due to the characteristics of the concentration-dependent exchange current density. The insights highlight the necessity to incorporate materials thermodynamics into electrochemical models to ensure self-consistent understandings of practical porous electrodes toward precision design and management.