Accordion Strain Accommodation Mechanism within the Epitaxially Constrained Electrode,ACS Energy Letters

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Accordion Strain Accommodation Mechanism within the Epitaxially Constrained Electrode
ACS Energy Letters ( IF 19.3 ) Pub Date : 2018-07-09 00:00:00 , DOI: 10.1021/acsenergylett.8b00829
Sung Joo Kim _{1,

2} , Donghee Chang ₃ , Kui Zhang ₁ , George Graham _{1,

2} , Anton Van der Ven ₃ , Xiaoqing Pan _{1,

4}

Affiliation

The tremendous benefits of all-solid-state Li-ion batteries will only be reaped if the cycle-induced strain mismatch across the electrode/electrolyte interfaces can be managed at the atomic scale to ensure that structural coherency is maintained over the lifetime of the battery. We have discovered a unique strain accommodation mechanism within an epitaxially constrained high-performance bronze TiO₂ (TiO₂-B) electrode that relieves coherency stresses that arise upon Li insertion. In situ transmission electron microscopy observation reveals the formation of anatase shear bands within the TiO₂-B crystal that play the same role that interface dislocations do to relieve growth stresses. While first-principles calculations indicate that anatase is the favored crystal structure of TiO₂ in the lithiated state, its continued propagation is suppressed by the epitaxial constraints of the substrate. This discovery reveals an accordion-like mechanism relying on an otherwise undesirable structural transformation that can be exploited to manage the cyclic strain mismatch across the electrode/electrolyte interfaces that plague all solid-state batteries.

中文翻译：

外延约束电极内的手风琴应变适应机制

全固态锂离子电池的巨大好处只有在电极/电解质界面上的循环感应应变失配能够在原子尺度上得到控制，以确保在整个电池寿命中保持结构一致性时，才能获得。。我们已经发现在外延约束的高性能青铜TiO ₂（TiO ₂ -B）电极内具有独特的应变适应机制，该机制可缓解因插入Li而产生的相干应力。原位透射电子显微镜观察揭示了TiO ₂内锐钛矿剪切带的形成-B晶体起着与界面位错缓解生长压力相同的作用。虽然第一性原理计算表明锐钛矿是处于锂化状态的TiO _2的首选晶体结构，但其继续传播受到衬底的外延约束的抑制。这一发现揭示了一种类似手风琴的机制，该机制依赖于其他不合需要的结构转换，可以利用该结构转换来管理困扰所有固态电池的跨电极/电解质界面的循环应变失配。

更新日期：2018-07-09

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