Electrochemical capacitance of clay minerals by diamine modification: Fid-Bau Portal

Electrochemical capacitance of clay minerals by diamine modification

Liao, Yi / Chai, Shan-Shan / Zhang, Wei-Bin / Yao, Yao / Yang, Jing-Lei / Yin, Yi / Li, Jia-Jun / Yang, Ze-Qin / Ma, Xue-Jing / Peng, Qiang

Abstract

Abstract Clay minerals, naturally occurring two-dimensional layered nanomaterials, hold significant interest in electrochemical energy storage. However, their practical use is hindered by the pronounced stacking and aggregation of layers. Here, we selected eight clay minerals of kaolinite, halloysite, montmorillonite, vermiculite, palygorskite, sepiolite, talc and chlorite, employed a simple chemical water bath method to insert diamine molecules with different chain lengths between the layers of these minerals. This approach aimed to prevent stacking and aggregation while allowing controlled expansion of the layer spacing. Subsequently, the montmorillonite (M) with relatively high specific capacitance were selected for further discussion. X-ray diffraction results show that the layer spacings of diamine (xDM, x = 2–6) modified montmorillonite (M/xDM) could be optimized within 1.189 nm and 1.455 nm, of which the butanediamine (4DM) pillared montmorillonite composites (M/4DM) exhibited the most suitable layer spacing of 1.362 nm for efficient Na2SO4 ion transportation. Additionally, the CeO2 loaded montmorillonite (CeO2-M) composites were further prepared by the same method to obtain diamine pillared CeO2 loaded montmorillonite (CeO2-M/xDM). The specific capacitance of CeO2 loaded and butanediamine pillared montmorillonite composites (CeO2-M/4DM) was 573.9 F g⁻¹, which was 33.9% higher than the counterpart without modification (CeO2-M). The assembled supercapacitor CeO2-M/4DM//AC exhibited almost no loss in capacitance after 10,000 cycles.

Highlights • A strategy for precise modulation of clay layer spacing using diamines applied to supercapacitor. • The effect of different layer spacing on electrochemical performance was explored. • Using this strategy to adjust the layer spacing of CeO2-loaded clay composites proves its scalability. • The designed clay-based composites electrodes show excellent electrochemical performance.