Електрохімія літій-манганової шпінелі, модифікованої церієм, в апротонному та водному електролітах

• Дата: 2025
• Автори: Shmatok, Yu. V., Globa, N. I., Sirosh, V. A., Romanova, I. V.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2025
• Теми: літій-манганова шпінель; допування; модифікація поверхні; апротонний електроліт; водний електроліт; питома ємність; кінетика; електрохімічна екстракція літію
• Онлайн доступ: https://www.cpts.com.ua/index.php/cpts/article/view/775
• Назва журналу: Chemistry, Physics and Technology of Surface

Modification of the structure and surface of spinel LiMn2O4 with metal ions is an effective way to improve its electrochemical characteristics. The paper examines the effect of doping with cerium ions on the structural and surface characteristics of spinels LiCexMn2-xO4 (х = 0, 0.01, 0.05 and 0.1), as well as their capacitive and cyclic characteristics in systems with aprotic and aqueous electrolytes. Using the X-ray diffraction method, it has been found that only a small part of cerium ions is incorporated into the spinel structure, and the excess cerium crystallizes in the form of a separate CeO2 phase. According to the data of scanning electron microscopy, the CeO2 phase exists in the form of individual non-agglomerated particles with a size of several tens of nanometers, which are in direct contact with spinel particles of 100–300 nm in size. Cyclic voltammetry and galvanostatic cycling methods were used to determine the specific, cyclic and kinetic characteristics of the synthesized materials in aprotic (1M LiPF6 in a mixture of ethylene carbonate:dimethyl carbonate:diethyl carbonate) and aqueous (5M LiNO3 in H2O) electrolytes. It is shown that the specific capacity of spinels depends on both the composition of the spinel itself and the type of electrochemical system. Depending on the spinel composition, the initial specific capacity in the aprotic system is 100–121 mA·h/g and    81–103 mA·h/g in the aqueous system. The obtained results demonstrate the overall positive effect of the structural and surface modification of spinel by cerium ions on its electrochemical behavior. Based on cyclic voltammetry data, a comparison of the kinetic characteristics of the studied spinel samples in aprotic and aqueous electrochemical systems was carried out, for which the lithium diffusion coefficient was calculated and the controlling mechanism of the electrochemical reaction was determined. A possibility of using synthesized spinel samples as materials for the electrochemical extraction of lithium from aqueous solutions is shown.