Proton-Conducting Polyoxometalates as Redox Electrolytes Synergistically Boosting the Performance of Self-Healing Solid-State Supercapacitors with Polyaniline

Abstract

Energy storage devices with high volumetric and gravimetric capacitance are in urgent demand due to the booming market of portable and wearable electronics. Using redox-active molecules as electrolytes is a strategy to improve the capacitance and energy density of solid-state supercapacitors (SCs). In this study, polyoxometalates (POMs) are applied as proton conductors and redox mediators in polyvinyl alcohol (PVA) electrolytes, which increase the capacitance of obtained SCs with polyaniline (PANI). H 3 PMo 12 O 40 -loaded PANI electrodes provide pseudocapacitance with an eight-electron Faraday reaction in a charge-discharge cycle. This has rarely been reported in SCs before. The largest capacitance of SCs with H 3 PMo 12 O 40 and H 3 PW 12 O 40 as electrolytes is 7.69 F/cm 2 (3840 F/g) based on a single electrode at 0.5 mA/cm 2 . In addition, POM electrolytes exhibit excellent self-healing ability, which is attributed to the rich hydrogen-bonding network between POMs and PVA. This study demonstrates that the capacitance of solid-state SCs is improved by using molecular redox-active electrolytes and showcases the potential of applying this strategy to other energy storage devices in the future.

Nanostructured Polymer Composite Electrolytes with Self-Assembled Polyoxometalate Networks for Proton Conduction

“…Ion-conducting polymer electrolytes have tremendous potential in a wide range of energy applications such as fuel cells, batteries, supercapacitors, and other energy storage and conversion devices. [1][2][3][4][5][6][7][8][9][10][11][12] Despite these promising applications, a key issue in polymer electrolytes is maximizing the ionic conductivity while simultaneously optimizing the mechanical performance, so as to prepare high conductive and high stable electrolyte membranes for practical use. 13 However, the facilitation of ion transport generally involves increasing the content of ionic groups or accelerating the segmental dynamics of polymer electrolytes, which inevitably causes the electrolyte membranes to become swollen or softened and thus sacrifice their mechanical strength.…”

Recent progress on novel current collector electrodes for energy storage devices: Supercapacitors

“…The assembled supercapacitor showed 200% stretchability without any loss in performance and nearly 100% capacitance retention after 600 charging/discharging cycles. Cheng et al (2020) reported fabrication of H 3 PMo 12 O 40 loaded polyaniline electrodes with polyoxometalates‐PVA redox active electrolyte and polyaniline as current collector. The developed supercapacitor showed areal capacitance of 7.69 F/cm 2 at 0.5 mA/cm 2 with energy density of 0.53 mWh/cm 2 .…”

Self-Healing Hydrophilic Porous Photothermal Membranes for Durable and Highly Efficient Solar-Driven Interfacial Water Evaporation

“…With the progress in supramolecular chemistry and synthetic chemistry, various self-healing polymers that are capable of healing damage by themselves to restore the mechanical and/or chemical properties have been Page 2 of 31 CCS Chemistry 3 successfully synthesized. [20][21][22][23] In addition, by combining self-healing polymers with functional materials, plenty of self-healing functional materials with superhydrophobicity, [24][25][26][27] antifouling, [28][29][30] electrical conductivity, [31][32][33][34] sensing, [35][36][37][38][39][40][41] and other functions [42][43][44][45][46][47][48][49][50] have been fabricated, significantly decreasing maintenance costs and promoting safety, reliability, and service life. The design and fabrication of self-healing materials with photothermal and water transportation capabilities that can repair their functions upon damage would be a judicious solution to increase the stability and service life of solar-driven interfacial evaporators.…”