Charge Transfer Band Gap as an Indicator of Hysteresis in Li-Disordered Rock Salt Cathodes for Li-Ion Batteries
Charge Transfer Band Gap as an Indicator of Hysteresis in Li-Disordered Rock Salt Cathodes for Li-Ion Batteries
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DOI：
10.1021/jacs.8b11413
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发表时间：
2019-07-24
影响因子：
15
通讯作者：
Tarascon, Jean-Marie
中科院分区：
文献类型：
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作者：
Jacquet, Quentin;Iadecola, Antonella;Tarascon, Jean-Marie
表现出阴离子和阳离子氧化还原的无序岩盐阴极由于其非常高的储能容量而被广泛研究。Mn基无序岩盐化合物显示出比Ni基材料高得多的能量效率，这是由于不同的电压滞后，分别为0.5和2V。为了理解这种差异的起源，我们在此报告的两个模型化合物，Li1.3Ni0.27Ta0.43O2和Li1.3Mn0.4Ta0.3O2的设计，并研究其电荷补偿机制，通过吸收和去除锂通过阿森纳的分析技术。我们表明，不同的电压滞后与镍或锰取代是由于不同的还原电位的阴离子氧化还原。我们合理化这样的发现通过DFT计算，并提出这种现象是嵌套在较小的电荷转移带隙的Ni基化合物相比，Mn的。总之，这些发现为设计下一代锂离子电池的基于阴离子氧化还原活性的高容量无序岩盐阴极材料提供了重要指导。
Disordered rock salt cathodes showing both anionic and cationic redox are being extensively studied for their very high energy storage capacity. Mn-based disordered rock salt compounds show much higher energy efficiency compared to the Ni-based materials as a result of the different voltage hysteresis, 0.5 and 2 V, respectively. To understand the origin of this difference, we herein report the design of two model compounds, Li1.3Ni0.27Ta0.43O2 and Li1.3Mn0.4Ta0.3O2, and study their charge compensation mechanism through the uptake and removal of Li via an arsenal of analytical techniques. We show that the different voltage hysteresis with Ni or Mn substitution is due to the different reduction potential for anionic redox. We rationalized such a finding by DFT calculations and propose this phenomenon to be nested in the smaller charge transfer band gap of the Ni-based compounds compared to that of the Mn ones. Altogether, these findings provide vital guidelines for designing high-capacity disordered rock salt cathode materials based on anionic redox activity for the next generation of Li ion batteries.