2024 AIChE Annual Meeting
Sensational Mxenes: Evolving the Manufacturing of Textile-Based Supercapacitors
The widespread use of portable electronics in everyday activities encourages interest in the research of wearable supercapacitors. Current methods to create textile-based supercapacitors (TSCs) involve the synthesis of conductive materials to coat fiber such as cotton or wool. Among various materials, MXenes, a family of two-dimensional transition metal carbides or nitrides, have gained significant attention. Methods of coating and different types of yarn are of particular interest for optimization to address limiting factors in current techniques. In comparing two yarns, wool and cotton, the wool yarn in comparison to the cotton yarn has higher MXene content on the yarn's surface when examined with X-ray Photoelectron Spectroscopy (XPS). Additionally, the wool yarn exhibited more pseudocapacitive behavior when compared to the cotton yarn due to its fiber’s increased aqueous electrolyte uptake. Yarn coating was previously done by simply dipping the yarn into the MXene colloidal solution and drying it under a continuous vacuum. This coating and drying method is a two-step process. To optimize the method, an auto-coater was developed to streamline yarn coating into a one-step process where the yarn is simultaneously coated and dried. Although this method is still undergoing refinement, the current auto-coater employs a fan and motor system. The motor, in conjunction with a shaft, spins the newly coated and dried yarn onto a spindle. Once the yarn is coated and run through a series of tests, the yarn is knitted into a TSC. Currently, the TSC is knitted by hand, but with the help of a Kniterate knitting machine, this process can be improved. The knitting machine can be programmed to knit electronic components that can be used in this research. In order to utilize the Kniterate machine, fundamentals of operation and coding knowledge are needed. Using a knitting machine offers several advantages; TSCs can be knitted with more consistent sizing than what can be done via hand knitting, mass production is more efficient, and the knitting environment is more controlled. Using wool fibers, the auto-coater, and the new Kniterate machine, the research of developing wearable MXene TSCs is expanding to include studying the effect of yarn substrate and processing on performance.