Co/Li-dual-site doping towards LiCoO2 as a high-voltage, fast-charging, and long-cycling cathode material,Journal of Materials Chemistry A

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Co/Li-dual-site doping towards LiCoO2 as a high-voltage, fast-charging, and long-cycling cathode material
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2022-01-27 , DOI: 10.1039/d1ta10612k
Shou-Xiao Chen ₁ , Chuan-Wei Wang ₁ , Yao Zhou ₁ , Jun-Ke Liu ₁ , Chen-Guang Shi ₂ , Guo-Zhen Wei ₃ , Bao-Yi Yin ₄ , Hao-Tian Deng ₁ , Si-Yu Pan ₁ , Ming-Jia Guo ₂ , Wei-Chen Zheng ₂ , Hao-Zhi Wang ₅ , You-Hong Jiang ₂ , Ling Huang ₂ , Hong-Gang Liao ₂ , Jun-Tao Li ₁ , Shi-Gang Sun ₂

Affiliation

The design of fast-charging, long-cycling, and high-voltage cathode materials remains challenging. Herein, through different strategies, Al and Nb/W are doped into the Co- and Li-sites in LiCoO₂ (LCO), respectively; according to density functional theory calculations, compared with the Co-site, doping at Li-site is thermodynamically unfavourable, which is primarily driven by the kinetic motif. We demonstrate that the Al-dopant at the Co-site inhibits the adverse phase transformation of LiCoO₂ under high voltage, while the Nb/W dopants intercalated within the Li-slab can serve as pillars that not only increase the interlayer spacing but also decrease the electronic coupling around Li⁺, thus increasing the population of highly active Li⁺ and enabling fast Li⁺ diffusion kinetics. Owing to the synergy effect from dual-site doping at both Co- and Li-sites, together with a discrete coating layer of niobium tungsten oxide (NWO) nanoparticles, the thus modified LiCoO₂ (denoted as ANW-LCO) cathode delivers highly stable and superior rate performance even under high voltage. Specifically, with a cut-off potential of 4.5 V, it displays a specific capacity of as high as 142.1 mA h g⁻¹ at 15C and can maintain a reversible capacity of 85.3 mA h g⁻¹ after 1000 cycles at 10C under 4.5 V, translating into a capacity retention of 60.4%. When evaluated at 4.6 V, it shows a capacity retention of as high as 77.5% after 100 cycles. When tested in all-solid-state lithium-ion batteries, it delivers a primal discharge specific capacity of 139 mA h g⁻¹ and retains 71% of its capacity after 200 cycles. The full-cell also demonstrates outstanding cycling stability, with a capacity retention of 71% after 500 cycles at 2C.

中文翻译：

Co/Li双位点掺杂LiCoO2作为高压、快速充电和长循环正极材料

快速充电、长循环和高压正极材料的设计仍然具有挑战性。_{在此，通过不同的策略，Al和Nb/W分别被掺杂到LiCoO 2} (LCO)中的Co位和Li位中；根据密度泛函理论计算，与Co-位点相比，Li-位点的掺杂在热力学上是不利的，这主要是由动力学基序驱动的。我们证明了 Co-site 处的 Al 掺杂剂抑制了 LiCoO ₂在高压下的不利相变，而嵌入 Li 板坯中的 Nb/W 掺杂剂可以作为柱子，不仅增加层间距，而且减少Li ⁺周围的电子耦合，从而增加了高活性 Li ^+的数量并实现快速的 Li ⁺扩散动力学。由于在 Co 位和 Li 位的双位掺杂的协同效应，以及铌钨氧化物 (NWO) 纳米粒子的离散涂层，因此改性的 LiCoO ₂ (表示为 ANW-LCO) 阴极可提供高度稳定即使在高电压下也具有出色的倍率性能。具体来说，截止电位为 4.5 V，它在 15C 时显示出高达 142.1 mA hg ^-1的比容量，并且可以保持 85.3 mA hg ^{-1的可逆容量}在 10C、4.5 V 下 1000 次循环后，容量保持率为 60.4%。在 4.6 V 下评估时，100 次循环后的容量保持率高达 77.5%。在全固态锂离子电池中进行测试时，它提供 139 mA hg ^-1的原始放电比容量，并在 200 次循环后保持其容量的 71%。全电池还表现出出色的循环稳定性，在 2C 下循环 500 次后容量保持率为 71%。

更新日期：2022-01-27

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