2D Amorphous Mo-Doped CoB for Bidirectional Sulfur Catalysis in Lithium Sulfur Batteries,Advanced Functional Materials

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2D Amorphous Mo-Doped CoB for Bidirectional Sulfur Catalysis in Lithium Sulfur Batteries
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2022-05-06 , DOI: 10.1002/adfm.202202766
Tao Feng ₁ , Teng Zhao ₁ , Nanxiang Zhang ₁ , Yuzhen Duan ₂ , Li Li _{1,

3,

4} , Feng Wu _{1,

3,

4} , Renjie Chen _{1,

3,

4}

Affiliation

The amorphous metal boride materials are attractive catalyst for advanced lithium sulfur batteries, but their catalytic mechanism remains unclear. Herein, 2D amorphous Mo-doped cobalt boride (Co₇Mo₃B) is designed for the first time as bidirectional sulfur catalysis by rapid chemical reduction. The atom cluster structure of Co₇Mo₃B is revealed by theoretical calculation. Electron paramagnetic resonance test further confirms that Co₇Mo₃B has interstitial compound structure characteristics. Experimental results show that the porous 2D nanosheets structure and the interaction of Mo, B, Co atoms contribute to enhanced conductivity, high long-chain lithium polysulfides affinity, and reversible Li₂S nucleation and dissociation, thus accelerating LiPSs reduction and Li₂S oxidation kinetics. In addition, the interstitial Co₇Mo₃B enables intercalation of Li and B during charging–discharging while keeping the structure stable. As a result, the S cathode with Co₇Mo₃B catalyst delivers good life (1000 cycles at 5 C), superior rate performance (10 C). Even at high sulfur areal loading of 6.79 mg cm^–2 and electrolyte/sulfur ratio of 5 μL mg^–1, the Co₇Mo₃B/S composite cathode still exhibits good areal capacity and capacity retention rate.

中文翻译：

用于锂硫电池双向硫催化的二维非晶钼掺杂钴

无定形金属硼化物材料是先进锂硫电池的有吸引力的催化剂，但其催化机制仍不清楚。在此，首次设计了二维无定形 Mo 掺杂硼化钴 (Co ₇ Mo _{3 B) 作为快速化学还原的双向硫催化。}通过理论计算揭示了Co ₇ Mo ₃ B的原子团簇结构。电子顺磁共振测试进一步证实Co ₇ Mo ₃B具有间隙复合结构特征。实验结果表明，多孔二维纳米片结构和 Mo、B、Co 原子的相互作用有助于提高电导率、高长链多硫化锂亲和性以及可逆的 Li ₂ S 成核和离解，从而加速 LiPSs 的还原和 Li ₂ S 的氧化动力学。此外，间隙型 Co ₇ Mo ₃ B 能够在充放电过程中插入 Li 和 B，同时保持结构稳定。因此，采用 Co ₇ Mo ₃ B 催化剂的 S 阴极具有良好的使用寿命（5 C 下 1000 次循环）和优异的倍率性能（10 C）。^{即使在 6.79 mg cm -2}的高硫面积负载下电解质/硫比为5 μL mg ^-1时，Co ₇ Mo ₃ B/S复合正极仍具有良好的面积容量和容量保持率。

更新日期：2022-05-06

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