AUTHOR=Bin Xiaoqing , Sheng Minhao , Que Wenxiu 

TITLE=Highly conductive V4C3Tx MXene-enhanced polyvinyl alcohol hydrogel electrolytes for flexible all-solid-state supercapacitors

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2024.1482072

DOI=10.3389/fchem.2024.1482072

ISSN=2296-2646

ABSTRACT=Hydrogel electrolytes are an integral part of flexible solid-state supercapacitors. To further improve the low ionic conductivity, large interfacial resistance and poor cycling stability for hydrogel electrolytes, the V4C3Tx MXene-enhanced polyvinyl alcohol hydrogel electrolyte was fabricated to enhance its mechanical and electrochemical performance. The high-conductivity V4C3Tx MXene (16465.3 S m -1 ) bonding transport network was embedded into the PVA-H2SO4 hydrogel electrolyte (PVA-H2SO4-V4C3Tx MXene). Results indicate that compared to the pure PVA-H2SO4 hydrogel electrolyte (105.3 mS cm -1 , 48.4%@2800 cycles), the optimal PVA-H2SO4-V4C3Tx MXene hydrogel electrolyte demonstrates high ionic conductivity (133.3 mS cm -1 ) and commendable long-cycle stability for the flexible solid-state supercapacitors (99.4%@5500 cycles), as well as favorable mechanical flexibility and self-healing capability. Besides, the electrode of the flexible solid-state supercapacitor with the optimal PVA-H2SO4-V4C3Tx MXene hydrogel as the solid-state electrolyte has a capacitance of 370 F g -1 with almost no degradation in capacitance even under bending from 0° to 180°. The corresponding energy density for flexible device is 4.6 Wh kg -1 , which is twice for that of PVA-H2SO4 hydrogel as the solid-state electrolyte.