Magnetic Field Effects in 2D Manganese Ditelluride Supercapacitors

Abstract

The specific capacitance of the material is significantly influenced by the structure's morphology. It thus becomes essential for supercapacitor materials to offer an increased surface area for redox activity. Recent exploration on telluride-based materials has garnered attention. As compared to the state-of-the-art transition metal supercapacitors, tellurides offer a wide voltage window of operation and a stable morphology. High specific capacitance of 135 F g⁻¹ at 0.5 A g⁻¹ for 2D manganese telluride (2D MnTe₂). This is approximately twice the specific capacitance as compared to its bulk counterpart (68 F g⁻¹) at 0.5 A g⁻¹. The changes in specific capacitance on application of magnetic fields are also tested. The morphological and chemical changes in the sample after the electrochemical measurements utilizing post-X-ray diffraction, post-X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and post-scanning electron microscopy are analyzed. A symmetric device (coin cell) is fabricated with 2D MnTe₂ which has a specific capacitance of ≈65 F g⁻¹ at 1 A g⁻¹ with an operating voltage window 1.2 V. Due to its large surface area and the amount of surface redox reactions occurring at the electrode, the 2D MnTe₂ electrode shows excellent rate capability. Herein, 2D tellurides can be a valuable addition providing a stable morphology for supercapacitor device operation.