Communication-Introduction of Polyurethane-Polyacrylic Acid as a Binder for Electrochemical Activation of Expanded Mesocarbon Microbeads in Organic Supercapacitors

The electrochemical activation is a common technique enhancing the capacitive performances of carbons in high-voltage supercapacitors while volume expansion during the activation process often makes the active materials detachment, dropping the capacitance. In this work, the KOH-neutralized polyurethane-crosslinked-polyacrylic acid (PUPAH_10-xK_x) polymers are proposed to replace the polyvinylidene fluoride (PVDF) as a binder for expanded mesocarbon microbead (EMCMB) electrodes to buffer the volume expansion. The effects of binder rheology, morphology and neutralization degree on the capacitive performance of EMCMB are investigated. Introducing PUPAH₆K₄ with moderate viscoelasticity to EMCMB forms an expansion-buffering electrode and promotes the electrochemical activation process.