Viable morphology control strategy enabled by EG solvothermal treatment
for high capacitance PEDOT:PSS films
Abstract
Thick and highly conductive PEDOT:PSS films with ideal morphologies, are
desirable as electrodes for supercapacitors. However, building uniform
micro-morphology without templates or composite strategies is a
formidable challenge, primarily caused by the inherent softness of
dominant PSS. Herein, we successfully realized morphology control,
transitioning from a layer-by-layer architecture to a porous structure
in thick PEDOT:PSS films by employing solvothermal method with ethylene
glycol (EG) as the solvent. The combined effect of high pressure and
temperature effectively drove EG to construct the microstructure of
thick PEDOT:PSS films by detaching insulating PSS chains and enhancing
PEDOT crystallinity, and simultaneously facilitated the formation of a
porous network through EG molecular tailoring. The achieved porous thick
PEDOT:PSS films delivered a high conductivity of 1644 S cm-1 and a
champion specific capacitance of 270 F cm-3, significantly surpassing
previously reports. The flexible all-solid-state supercapacitor
assembled based on the films displayed an excellent specific capacitance
of 97.8 F cm-3 and an energy density of 8.7 mWh cm-3, representing the
highest values for pure PEDOT:PSS-based supercapacitors. This research
provides an effective novel method for conducting polymer morphology
control and promotes the applications of PEDOT:PSS in the field of
energy storage.