High performance δ-Bi2O3 nanosheets transformed Bi2S3 nanoflakes interconnected nanosheets as negative electrode for supercapacitor applications

Progress of negative electrode for supercapacitors (SCs) is most important topic of the recent advanced technological era for the next generation energy storage devices and applications. Bismuth oxide (δ-Bi2O3) with high specific capacitance has emerged as a promising negative electrode material for SCs. Herein, a facile two-step synthesis strategy has been proposed to fabricate Bi2S3 nanoflakes interconnected nanosheets electrode by the conversion of electro-deposited as-prepared δ-Bi2O3 nanosheets followed by hydrothermal route. From the comparison study, it is concluded that Bi2S3 nanoflakes interconnected nanosheets exhibit ultrahigh specific capacitance (565 F g−1 at 1 A g−1) and exceptional cycling stability (∼98% retention after 2000 cycles) as a negative electrode material. Meanwhile, δ-Bi2O3 nanosheets electrode has only reached to 474 F g−1 at 1 A g−1 with poor retention of ∼46%. The improved and better performance of Bi2S3 nanoflakes interconnected nanosheets electrode is attributed to high conductivity due to sulfurization. The current fabrication strategy would provide valuable insights to prepare Bi-based nano-materials for high-performance energy storage technologies and beyond.