Synergistic combination of carbon conductive and flexural additives for flexible screen-printed supercapacitor electrodes

Wearable electronics have attracted attention due to their many potential applications ranging from body-worn entertainment, protection, sensing, to communication and medical purposes. To function, energy supplying devices are necessary, which are required to be lightweight, flexible, and to possess high energy and power performance. Herein, a strategy was proposed to maximise the energy and power performance of textile supercapacitors via carbon conductive additives with higher percolation threshold compared to Super C65, the carbon black of choice in supercapacitor and battery electrode manufacture. Additionally, functionalised carbon nanotubes were investigated as carbon flexural additives, in order to improve the electrodes flexibility. By replacing with a higher surface area carbon black, the activated carbon content in the electrode increased by 10%, facilitating a measurable increase in energy density, without sacrificing the electrical properties of the printed active layers. Additionally, the introduction of functionalised carbon nanotubes allowed a substantial increase of flexural properties in the printed active layers. Regarding the electrochemical performance, the high surface area carbon black provided a boost in the power density, while the carbon nanotubes were regarded as energy density boosters. In summary, their use is highly recommended in order to achieve better electrochemical performances and flexural properties in flexible supercapacitor electrodes.