Novel architectures for high-performance supercapacitors based on 2D ‎materials

The growing demand for efficient energy storage systems in renewable energy and portable electronics highlights the need for advanced technologies. Supercapacitors, with their exceptional power density, rapid charge-discharge capabilities, and superior cycle stability, offer a promising solution but are limited by low energy density. This challenge underscores the transformative potential of 2D materials, such as graphene and MXenes, in bridging this gap. This dissertation investigates high-performance supercapacitors using 2D materials. Graphene-based supercapacitors, fabricated with rotationally stacked bilayer graphene synthesized via CVD, achieved a specific gravimetric capacitance (SGC) of up to 316 F g⁻¹ with 100% retention after 10,000 cycles in Na₂SO₄ electrolyte. In addition, nonfunctionalized MXenes synthesized via CVD were studied with both aqueous and ionic liquid (IL) electrolytes. MXenes paired with [BMIM]BF₄ IL electrolyte achieved a specific energy density of 391 Wh kg⁻¹, more than twice the 144 Wh kg⁻¹ achieved in aqueous electrolytes. A record SGC of 5160 F g⁻¹ was also obtained using the LiTFSI-VC electrolyte, significantly surpassing most state-of-the-art supercapacitors but limited by stability challenges. Separator studies revealed that filter paper enhanced capacitance while Celgard improved cycle stability, emphasizing the importance of device configuration on performance. The comparative analysis suggests that graphene holds potential for long-term stability in portable electronics, while MXenes show promise for high-energy applications like renewable energy stabilization and rapid-charging systems in transportation. This work highlights the immense potential of 2D materials in advancing supercapacitor technologies, emphasizing the need for further research into material stability and electrolyte compatibility.