Bifunctional effect of laser-induced nucleation-preferable microchannels and in situ formed LiF SEI in MXenes for stable lithium-metal batteries,Journal of Materials Chemistry A

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Bifunctional effect of laser-induced nucleation-preferable microchannels and in situ formed LiF SEI in MXenes for stable lithium-metal batteries
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2020-06-10 , DOI: 10.1039/d0ta04302h
Cheng Xiong _{1,

2,

3,

4} , Zhenyu Wang _{1,

2,

3,

4} , Xudong Peng _{1,

2,

3,

4} , Yang Guo _{4,

5,

6,

7} , Shaolin Xu _{4,

5,

6,

7} , Tianshou Zhao _{1,

2,

3,

4}

Affiliation

Lithium (Li) metal is considered to be the ultimate choice of anode for high energy density lithium-based batteries. However, the uncontrollable dendrite growth, in particular at large current rates, hinders its practical applications. Herein, a novel MXene/TiO₂ membrane with aligned microchannels as the lithium host is fabricated using a femtosecond laser, with numerous lithiophilic sites (TiO₂) spatial-precisely synthesized on the channel walls. Benefiting from the exposed nanometer-scale edges of the MXene, a favorable Li⁺ ion migration into the channels is achieved by the well-manipulated electric field, thus resulting in preferential Li deposition inside the microchannels. Moreover, a lithium fluoride (LiF) reinforced SEI is generated on the top surface of the host upon electrochemical cycling thanks to the built-in fluorine terminals in the MXene. As a result, a long lifespan of 750 cycles (1500 hours) with a coulombic efficiency of 98.8% is achieved at 1 mA cm⁻². Even at an ultrahigh current density of 20 mA cm⁻², a lifespan of 500 cycles with a coulombic efficiency of 95.9% is still delivered.

中文翻译：

激光诱导成核的微通道的双功能效应和在MXene中原位形成LiF SEI的稳定锂金属电池

锂（Li）被认为是高能量密度锂基电池负极的最终选择。然而，不可控制的枝晶生长，特别是在大电流速率下，阻碍了其实际应用。本文中，使用飞秒激光制造了具有对准的微通道作为锂主体的新型MXene / TiO ₂膜，在通道壁上空间精确地合成了许多亲硫性位点（TiO ₂）。得益于MXene暴露的纳米级边缘，有利的Li ⁺通过良好控制的电场，离子迁移到通道中，从而导致锂在微通道内部优先沉积。此外，由于MXene中内置的氟末端，电化学循环时，主体的顶部表面会生成氟化锂（LiF）增强的SEI。结果，在1mA cm ^-2处实现了750个循环（1500小时）的长寿命和98.8％的库仑效率。即使在20 mA cm ^-2的超高电流密度下，仍可提供500个循环的寿命，库仑效率为95.9％。

更新日期：2020-07-21

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