Lithiation Mechanism and Improved Electrochemical Performance of TiSnSb-Based Negative Electrodes for Lithium-Ion Batteries,Chemistry of Materials

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Lithiation Mechanism and Improved Electrochemical Performance of TiSnSb-Based Negative Electrodes for Lithium-Ion Batteries
Chemistry of Materials ( IF 7.2 ) Pub Date : 2021-10-22 , DOI: 10.1021/acs.chemmater.1c01809
Joop Enno Frerichs ₁ , Mirco Ruttert ₂ , Jonas Koppe ₁ , Mathis Radzieowski ₃ , Martin Winter _{2,

4} , Tobias Placke ₂ , Michael Ryan Hansen ₁

Affiliation

Lithium alloying materials are promising candidates to replace the current intercalation-type graphite negative electrode materials in lithium-ion batteries (LIBs) due to their high specific capacity and relatively low cost. Here, we investigate the electrochemical performance of TiSnSb regarding its charge/discharge cycling stability as a negative electrode material in LIB cells. To assess a more practical performance with respect to a limited active lithium content in LIB full-cells, we evaluate the impact of pre-lithiation for TiSnSb with respect to the cycling stability in a NCM111||TiSnSb cell setup. The observation of the individual electrode potentials reveals comprehensive insights into the ongoing cell chemistry, showing that clear performance improvements can be achieved via pre-lithiation. Furthermore, the lithiation mechanism of TiSnSb is systematically studied via ex situ⁷Li magic-angle spinning (MAS) nuclear magnetic resonance (NMR), ex situ X-ray diffraction, and static ex situ¹¹⁹Sn wideband uniform rate smooth truncation Carr–Purcell Meiboom–Gill (CPMG) WCPMG NMR experiments. For comprehensive references regarding the isotropic ⁷Li shift of the Li–Sb intermetallic phases, all thermodynamically stable Li–Sb intermetallics of the binary Li–Sb systems have been synthesized and subsequently characterized by ⁷Li MAS NMR. Combined, our measurements for lithiated TiSnSb do not give any evidence for the formation of Li–Sn and Li–Sb intermetallics related to crystalline bulk phases (Li₇Sn₃, Li₇Sn₂, Li₃Sb, and Li₂Sb) as has been previously reported. In contrast, unique insights obtained from static ex situ¹¹⁹Sn WCPMG NMR and ex situ XRD measurements reveal the formation of ternary Li–Sb–Sn species during lithiation, which can be assigned to the intermetallic phase Li_2.8SbSn_0.2. Additionally, the ⁷Li MAS NMR measurements combined with the observed discharge capacity reveal a second Li species, which we assign to an amorphous Li–Sn phase.

中文翻译：

锂离子电池用 TiSnSb 基负极的锂化机制和改进的电化学性能

锂合金材料由于其高比容量和相对较低的成本，是替代锂离子电池（LIB）中当前嵌入型石墨负极材料的有希望的候选材料。在这里，我们研究了 TiSnSb 作为 LIB 电池负极材料的充放电循环稳定性方面的电化学性能。为了在 LIB 全电池中有限的活性锂含量方面评估更实用的性能，我们评估了 TiSnSb 预锂化对 NCM111||TiSnSb 电池设置中循环稳定性的影响。单独电极电位的观察揭示了全面见解正在进行的电池化学，显示出明显的性能改进，可以实现通过预锂化。此外，TiSnSb的锂化机构被系统地研究通过易地⁷栗魔角旋转（MAS）核磁共振（NMR），易地X射线衍射，和静态易地¹¹⁹ Sn的宽带均匀速率平滑截断卡尔赛尔Meiboom-Gill (CPMG) WCPMG 核磁共振实验。对于关于Li-Sb 金属间相的各向同性⁷ Li 位移的综合参考，已经合成了二元 Li-Sb 系统的所有热力学稳定的 Li-Sb 金属间化合物，随后用⁷李 MAS 核磁共振。结合起来，我们对锂化 TiSnSb 的测量没有给出任何与晶体体相（Li ₇ Sn ₃、Li ₇ Sn ₂、Li ₃ Sb 和 Li ₂ Sb）相关的 Li-Sn 和 Li-Sb 金属间化合物形成的证据，如之前已经报道过。相比之下，从静态非原位¹¹⁹ Sn WCPMG NMR 和非原位XRD 测量获得的独特见解揭示了锂化过程中三元 Li-Sb-Sn 物种的形成，这可以归因于金属间相 Li _2.8 SbSn _0.2。此外，⁷Li MAS NMR 测量结合观察到的放电容量揭示了第二种 Li 物质，我们将其指定为非晶态 Li-Sn 相。

更新日期：2021-11-09

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