A stretchable vertically stacked microsupercapacitor with kirigami-bridged island structure: MnO2/graphene/Poly(3,4-ethylenedioxythiophene) nanocomposite electrode through pen lithography

Although portable and wearable devices have recently attracted considerable attention due to the increasing demands for stretchable power sources, their high fabrication costs as well as lack of mechanical strength and integration capability limit the utilization of these devices. Herein we developed an array of 3 x 3 micro-supercapacitors (MSCs) that is mechanically stretchable by attaching MnO2 /graphene/poly (3,4-ethylenedioxythiophene)-based nanocomposite on a kirigami-bridged island substrate; the electrodes were simply drawn using pen lithography without following any conventional complicated processing. The structure can dissipate an external stress involved in the deformation of the electrode and delocalize any unwanted excessive strain over the entire interconnected MSCs. The results show that such a stretchable MSC array exhibits an areal specific capacitance of 23.04 mF cm(-2) and can be stretched by up to 200% at 3.6 V without showing any degradation in electrochemical performance. In addition, 94% of the initial capacitance is maintained after 5600 times of continuously stretching and releasing these MSCs by the application of a tensile strain. The output voltage and capacitance can be adjusted by using parallel or series arrangements of individual MSCs. Furthermore, these MSCs can be directly applied on the human skin and can maintain their electrochemical performance with repeated body movements.