Zukalová Markéta, Fabián Martin, Porodko Olena, Vinarčíková Monika, Pitňa Lásková Barbora, Kavan Ladislav
J. Heyrovský Institute of Physical Chemistry, Czech Acad. Sci. Dolejškova 3, CZ-18223, Prague 8 Czech Republic
Institute of Geotechnics, Slovak Academy of Sciences Watsonova 45 040 01 Košice Slovak Republic.
RSC Adv. 2023 Jun 7;13(25):17008-17016. doi: 10.1039/d3ra01496g. eCollection 2023 Jun 5.
A novel lithiated high-entropy oxychloride Li(ZnMgCoCu)FeOCl (LiHEOFeCl) with spinel structure belonging to the cubic 3̄ space group is synthesized by a mechanochemical-thermal route. Cyclic voltammetry measurement of the pristine LiHEOFeCl sample confirms its excellent electrochemical stability and the initial charge capacity of 648 mA h g. The reduction of LiHEOFeCl starts at 1.5 V Li/Li, which is outside the electrochemical window of the Li-S batteries (1.7/2.9 V). The addition of the LiHEOFeCl material to the composite of carbon with sulfur results in improved long-term electrochemical cycling stability and increased charge capacity of this cathode material in Li-S batteries. The carbon/LiHEOFeCl/sulfur cathode provides a charge capacity of 530 mA h g after 100 galvanostatic cycles, which represents 33% increase as compared to the charge capacity of the blank carbon/sulfur composite cathode after 100 cycles. This considerable effect of the LiHEOFeCl material is assigned to its excellent structural and electrochemical stability within the potential window of 1.7 V/2.9 V Li/Li. In this potential region, our LiHEOFeCl has no inherent electrochemical activity. Hence, it acts solely as an electrocatalyst accelerating the redox reactions of polysulfides. This can be beneficial for the performance of Li-S batteries, as evidenced by reference experiments with TiO (P90).
通过机械化学-热法合成了一种具有立方3̄空间群尖晶石结构的新型锂化高熵氯氧化物Li(ZnMgCoCu)FeOCl（LiHEOFeCl）。对原始LiHEOFeCl样品进行循环伏安法测量，证实了其优异的电化学稳定性以及648 mA h g的初始充电容量。LiHEOFeCl的还原起始于1.5 V（相对于Li/Li），这超出了锂硫电池的电化学窗口（1.7/2.9 V）。将LiHEOFeCl材料添加到碳与硫的复合材料中，可提高该锂硫电池正极材料的长期电化学循环稳定性，并增加充电容量。碳/LiHEOFeCl/硫正极在100次恒电流循环后提供530 mA h g的充电容量，与空白碳/硫复合正极在100次循环后的充电容量相比增加了33%。LiHEOFeCl材料的这种显著效果归因于其在1.7 V/2.9 V（相对于Li/Li）电位窗口内优异的结构和电化学稳定性。在该电位区域，我们的LiHEOFeCl没有固有的电化学活性。因此，它仅作为一种电催化剂加速多硫化物的氧化还原反应。这对锂硫电池的性能可能是有益的，如用TiO（P90）进行的参考实验所证明的那样。
