The design and development of self-charging supercapacitor power cells are rapidly gaining interest due to their ability to convert and store energy in an integrated device. Here, we have demonstrated the fabrication of a self-charging supercapacitor using siloxene sheets as electrodes and siloxene-based polymeric piezofiber separator immobilized with an ionogel electrolyte. The self-charging properties of the fabricated device subjected to various levels of compressive forces showed their ability to self-charge up to a maximum of 207 mV. The mechanism of self-charging process in the fabricated device is discussed via “piezoelectrochemical effect” with the aid of piezoelectrochemical spectroscopy measurements. These studies revealed the direct evidence of the piezoelectrochemical phenomenon involved in the energy conversion and storage process in the fabricated device. This study can provide insight towards understanding the energy conversion process in self-charging supercapacitors, which is of significance considering the state of the art of piezoelectric driven self-charging supercapacitors.

Silicon-based materials have attracted considerable interest for the development of energy storage devices because of their ease of integration with the existing silicon semiconductor technology. Herein, we have prepared siloxene sheets—a two-dimensional (2D) silicon material—and investigated their energy storage properties via fabrication of a symmetric supercapacitor (SSC) device containing 0.5 M tetraethylammonium tetrafluoroborate as the electrolyte. The formation of 2D siloxene sheets functionalized with oxygen, hydrogen, and hydroxyl groups was confirmed through X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and laser Raman mapping analyses. Cyclic voltammetric studies of the siloxene SSC device revealed the presence of pseudocapacitance in the siloxene sheets that arose from an intercalation/deintercalation phenomenon. The galvanostatic charge–discharge profiles of the device displayed sloped symmetric triangular curves with a maximum specific capacitance of 2.18 mF cm⁻², high energy density of 9.82 mJ cm⁻², good rate capability, and excellent cycling stability of 98% capacitance retention after 10 000 cycles. The siloxene SSC device delivered a maximum power density of 272.5 mW cm⁻², which is higher than those of other silicon- and carbon-based SSCs, highlighting their potential for application in energy storage.