First-Principles Study on the Interplay of Strain and State-of-Charge with Li-Ion Diffusion in the Battery Cathode Material LiCoO2,ACS Applied Materials & Interfaces

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First-Principles Study on the Interplay of Strain and State-of-Charge with Li-Ion Diffusion in the Battery Cathode Material LiCoO2
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2023-11-09 , DOI: 10.1021/acsami.3c14444
Zizhen Zhou _{1,

2} , Claudio Cazorla ₃ , Bo Gao _{2,

4} , Huu Duc Luong ₂ , Toshiyuki Momma ₁ , Yoshitaka Tateyama _{1,

2,

5}

Affiliation

Cathode degradation of Li-ion batteries (Li⁺) continues to be a crucial issue for higher energy density. A main cause of this degradation is strain due to stress induced by structural changes according to the state-of-charge (SOC). Moreover, in solid-state batteries, a mismatch between incompatible cathode/electrolyte interfaces also generates a strain effect. In this respect, understanding the effects of the mechanical/elastic phenomena associated with SOC on the cathode performance, such as voltage and Li⁺ diffusion, is essential. In this work, we focused on LiCoO₂ (LCO), a representative LIB cathode material, and investigated the effects of biaxial strain and hydrostatic pressure on its layered structure and Li⁺ transport properties through first-principles calculations. With the nudged elastic band technique and molecular dynamics, we demonstrated that in Li-deficient LCO, compressive biaxial strain increases the Li⁺ diffusivity, whereas tensile biaxial strain and hydrostatic pressure tend to suppress it. Structural parameter analysis revealed the key correlation of “Co layer distances” with Li⁺ diffusion instead of “Li layer distances”, as ordinarily expected. Structural analysis further revealed the interplay between the Li–Li Coulomb interaction, SOC, and Li⁺ diffusion in LCO. The activation volume of LCO under hydrostatic pressure was reported for the first time. Moreover, vacancy formation energy calculations showed that the Li intercalation potential could be decreased under compressive biaxial strain due to the weakening of the Li–O bond interaction. The present findings may serve to improve the control of the energy density performance of layered cathode materials.

中文翻译：

电池正极材料 LiCoO2 中应变和荷电状态与锂离子扩散相互作用的第一性原理研究

锂离子电池（Li ⁺）的阴极退化仍然是提高能量密度的关键问题。这种退化的主要原因是由于充电状态 (SOC) 引起的结构变化引起的应力而产生的应变。此外，在固态电池中，不兼容的阴极/电解质界面之间的不匹配也会产生应变效应。在这方面，了解与 SOC 相关的机械/弹性现象对阴极性能（例如电压和 Li ⁺扩散）的影响至关重要。在本工作中，我们重点研究了具有代表性的LIB正极材料LiCoO ₂ (LCO)，通过第一性原理计算研究了双轴应变和静水压对其层状结构和Li ^{+输运性能的影响。}通过推动弹性带技术和分子动力学，我们证明了在缺锂的 LCO 中，压缩双轴应变会增加 Li ⁺扩散率，而拉伸双轴应变和静水压力往往会抑制它。^{结构参数分析揭示了“Co层距离”与Li +}扩散的关键相关性，而不是通常预期的“Li层距离”。^{结构分析进一步揭示了 Li-Li 库仑相互作用、SOC 和 LCO 中 Li +}扩散之间的相互作用。首次报道了LCO在静水压力下的活化体积。此外，空位形成能计算表明，由于Li-O键相互作用减弱，在双轴压缩应变下，Li嵌入势可能会降低。目前的发现可能有助于改善层状正极材料能量密度性能的控制。

更新日期：2023-11-09

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