Hybrid Iodobismuthates Formed by Mechanochemical Synthesis as Pseudocapacitor Electrode Materials

Abstract

Supercapacitors, as a complementary type of energy storage device between secondary batteries and conventional capacitors, show the advantages of high-power density and stable cyclability. However, there are still challenges that remain to be solved, such as their relatively low energy density compared with secondary batteries. Herein, we report a new class of materials for supercapacitors, specifically two organic/inorganic hybrid iodobismuthate materials, 2-aminothiazolium bismuth iodide ([AT][BiI4]) and tetrabutylammonium bismuth iodide ([TBA]3[Bi3I12]). Both materials were synthesised by mechanochemistry, which is a green route with lower energy and resource consumption compared with solution-based methods.[TBA]3[Bi3I12] was also synthesised by precipitation for comparison. We tested the electrochemical performance of these materials using a three-electrode system and bismuth was shown to provide the redox active centre. The results illustrate that the mechanochemically-synthesised materials have higher performance, which suggests that further study of mechanochemical synthesis for hybrid iodobismuthates would be fruitful.