Tailoring of gradient particles of Li rich layered cathodes with mitigated voltage decay for lithium ion batteries.
Tailoring of gradient particles of Li rich layered cathodes with mitigated voltage decay for lithium ion batteries.
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DOI：
10.1021/acsami.0c10410
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发表时间：
2020-08
影响因子：
9.5
通讯作者：
Xiaokang Ju;X. Hou;Thomas Beuse;Zhongqing Liu;Leilei Du;Jan‐Paul Brinkmann;Elie Paillard;Taihong Wang
中科院分区：
文献类型：
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作者：
Xiaokang Ju;X. Hou;Thomas Beuse;Zhongqing Liu;Leilei Du;Jan‐Paul Brinkmann;Elie Paillard;Taihong Wang
循环期间的电压衰减仍然是富Li阴极的主要问题。最近，增加Ni含量已被认为是缓解该问题的有效方法，尽管其导致较低容量的材料。为了找到电压衰减和高容量之间的平衡，已经制备了具有过渡金属浓度梯度的富Li材料的颗粒。由于电压衰减是由主要发生在颗粒表面的氧损失和相变引起的，因此Ni含量被设计为具有从颗粒表面到本体的负浓度梯度。为此，将微米尺寸的Li1.20Ni0.13Co0.13Mn0.54O2颗粒与小得多的LiNi0.8Co0.1Mn0.1O2颗粒混合，以在较大颗粒上形成小颗粒的沉积物。在煅烧后处理期间，随着LiNi0.8Co0.1Mn0.1O2中的Ni离子渗透到Li1.20Ni0.13Co0.13Mn0.54O2中，实现了Ni的浓度梯度。梯度样品显示出上级的循环性能和电压保持以及改进的安全性。这项系统的研究探讨了一种材料模型，该模型结合了富锂和高镍层状阴极，可有效地在缓解的电压衰减和高能量密度之间建立平衡。
Voltage decay during cycling is still a major issue for Li rich cathodes. Recently, the increase of the Ni content has been recognized as an effective way to mitigate this problem, although it leads to lower capacity materials. In order to find a balance between voltage decay and high capacity, particles of Li rich materials with concentration gradients of transition metals have been prepared. Since voltage decay is caused by oxygen loss and phase transition that occur mainly at the particle surface, the Ni content is designed with a negative concentration gradient from the surface to the bulk of particles. To do so, micro sized Li1.20Ni0.13Co0.13Mn0.54O2 particles are mixed with much smaller LiNi0.8Co0.1Mn0.1O2 particles to form deposits of the small particles onto the larger particles. The concentration gradient of Ni is achieved as the Ni ions in LiNi0.8Co0.1Mn0.1O2 penetrate into Li1.20Ni0.13Co0.13Mn0.54O2 during a calcination post treatment. Gradient samples show superior cycling performance and voltage retention as well as improved safety. This systematic study explores a material model combining Li rich and high Ni layered cathodes that is shown to be effective in creating balance between mitigated voltage decay and high energy density.