Mannayil Jasna, Pitkänen Olli, Mannerkorpi Minna, Kordas Krisztian
Microelectronics Research Unit, University of Oulu Erkki Koiso-Kanttilan katu 3 90570 Oulu Finland.
Research Unit of Health Sciences and Technology, University of Oulu 90220 Oulu Finland
Nanoscale Adv. 2024 Jul 18;6(18):4647-4656. doi: 10.1039/d4na00368c. eCollection 2024 Sep 10.
MoS is a well-known 2D transition metal dichalcogenide (TMD) with feasibility for energy storage applications due to its eco-friendliness and high electroactive surface area. Electrodes based on MoS are typically made by either immobilizing its multiphase nanocomposites, having binders and conductive fillers, or by directly growing the materials on current collectors. In this work, we follow and optimize this latter approach by applying a hydrothermal route to directly synthesize MoS nanostructures on carbon cloth (MoS@CC) hence enabling binder-free current collector electrodes. Raman spectroscopy and electron microscopy analyses confirmed the formation of 2H MoS nanosheets with hexagonal structure. The as-prepared electrodes were used to assemble symmetric supercapacitor cells, whose performance were tested in various types of electrolytes. Electrochemical measurements indicate that both precursor concentration and growth time significantly affect the device performance. Under optimized conditions, specific capacitance up to 226 F g (at 1 A g in 6 M KOH) was achieved, with corresponding energy and power densities of 5.1 W h kg and 2.1 W kg. The device showed good stability, retaining 85% capacitance after 1000 cycles. Furthermore, the electrodes assessed in PYR14-TFSI showed energy and power densities of up to 26.3 W h kg and 2.0 kW kg, respectively, indicating their feasibility not only in aqueous but also in ionic liquid electrolytes. In addition, galvanostatic charge/discharge measurements conducted on devices having footprint sizes from 1 cm to 25 cm show very similar specific capacitances, which proves scalability and thus the practical relevance of the binder-free electrodes demonstrated in this study.
二硫化钼是一种著名的二维过渡金属二硫属化物（TMD），因其环保性和高电活性表面积而具有用于储能应用的可行性。基于二硫化钼的电极通常通过固定其具有粘合剂和导电填料的多相纳米复合材料来制备，或者通过在集流体上直接生长材料来制备。在这项工作中，我们采用水热法直接在碳布上合成二硫化钼纳米结构（MoS@CC），从而实现无粘合剂的集流体电极，以此来遵循并优化后一种方法。拉曼光谱和电子显微镜分析证实了具有六边形结构的2H二硫化钼纳米片的形成。所制备的电极用于组装对称超级电容器电池，并在各种类型的电解质中测试其性能。电化学测量表明，前驱体浓度和生长时间均显著影响器件性能。在优化条件下，在6 M KOH中1 A g时实现了高达226 F g的比电容，相应的能量密度和功率密度分别为5.1 W h kg和2.1 W kg。该器件表现出良好的稳定性，在1000次循环后保留85%的电容。此外，在PYR14-TFSI中评估的电极分别显示出高达26.3 W h kg和2.0 kW kg的能量密度和功率密度，这表明它们不仅在水性电解质中而且在离子液体电解质中都具有可行性。此外，对占地面积从1 cm到25 cm的器件进行的恒电流充/放电测量显示出非常相似的比电容，这证明了可扩展性，从而证明了本研究中展示的无粘合剂电极的实际相关性。
