Invernizzi Ronan, Guerlou-Demourgues Liliane, Weill François, Lemoine Alexia, Dourges Marie-Anne, Baraille Isabelle, Flahaut Delphine, Olchowka Jacob
CNRS, University of Bordeaux, Bordeaux INP, ICMCB UMR CNRS #5026, F-33600 Pessac, France.
RS2E, Réseau Français sur le Stockage Electrochimique de l'Energie, FR CNRS #3459, CEDEX 1, F-80039 Amiens, France.
Materials (Basel). 2021 Apr 29;14(9):2325. doi: 10.3390/ma14092325.
Nanostructuration is one of the most promising strategies to develop performant electrode materials for energy storage devices, such as hybrid supercapacitors. In this work, we studied the influence of precipitation medium and the use of a series of 1-alkyl-3-methylimidazolium bromide ionic liquids for the nanostructuration of β(III) cobalt oxyhydroxides. Then, the effect of the nanostructuration and the impact of the different ionic liquids used during synthesis were investigated in terms of energy storage performances. First, we demonstrated that forward precipitation, in a cobalt-rich medium, leads to smaller particles with higher specific surface areas (SSA) and an enhanced mesoporosity. Introduction of ionic liquids (ILs) in the precipitation medium further strongly increased the specific surface area and the mesoporosity to achieve well-nanostructured materials with a very high SSA of 265 m/g and porosity of 0.43 cm/g. Additionally, we showed that ILs used as surfactant and template also functionalize the nanomaterial surface, leading to a beneficial synergy between the highly ionic conductive IL and the cobalt oxyhydroxide, which lowers the resistance charge transfer and improves the specific capacity. The nature of the ionic liquid had an important influence on the final electrochemical properties and the best performances were reached with the ionic liquid containing the longest alkyl chain.
纳米结构化是开发用于储能设备（如混合超级电容器）的高性能电极材料最有前景的策略之一。在这项工作中，我们研究了沉淀介质以及一系列1-烷基-3-甲基咪唑溴化物离子液体对β(III)羟基氧化钴纳米结构化的影响。然后，从储能性能方面研究了纳米结构化的效果以及合成过程中使用的不同离子液体的影响。首先，我们证明在富钴介质中进行正向沉淀会产生具有更高比表面积（SSA）和更高介孔率的更小颗粒。在沉淀介质中引入离子液体（ILs）进一步显著提高了比表面积和介孔率，从而获得具有265 m²/g的非常高比表面积和0.43 cm³/g孔隙率的良好纳米结构化材料。此外，我们表明用作表面活性剂和模板的离子液体还能使纳米材料表面功能化，导致高离子导电性离子液体与羟基氧化钴之间产生有益的协同作用，降低电阻电荷转移并提高比容量。离子液体的性质对最终的电化学性能有重要影响，含最长烷基链的离子液体表现出最佳性能。
