Publications by authors named "Brian Evanko"

Article Synopsis
  • Redox-enhanced electrochemical capacitors (redox-ECs) outperform traditional capacitors due to the use of redox-active electrolytes, leading to higher energy density and more stable power output.
  • This study focuses on the electrochemical processes of a specific dual redox system involving pentyl viologen/bromide and mesoporous carbon electrodes (CMK-8) to enhance device performance.
  • Key findings suggest that optimal charging conditions (1.5 V voltage, 0.5 A/g rate) maximize energy delivery by enabling complete reduction of viologen molecules and achieving an effective balance between diffusion and adsorption processes.
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Article Synopsis
  • Research in energy storage is merging to create systems that combine the high energy density of batteries with the stability and power of capacitors, using redox-active electrolytes for enhanced performance.
  • Despite the potential, aqueous redox-enhanced electrochemical capacitors face challenges like poor cycle life and cross-diffusion issues.
  • The study introduces a novel method utilizing a liquid-to-solid phase transition for redox storage, significantly improving energy density and stability, achieving a 64 W·h/kg energy capacity with excellent power density and cycle longevity.
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A plasmonic liquid junction photovoltaic cell with greatly improved power conversion efficiency is described. When illuminated with simulated sunlight, the device (Au-TiO/V(0.018 M), V(0.

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The performance of redox-enhanced electrochemical capacitors (redox ECs) is substantially improved when oxidized catholyte (bromide) and reduced anolyte (viologen) are retained within the porous electrodes through reversible counterion-induced solid complexation. Investigation of the mechanism illustrates design principles and identifies pentyl viologen/bromide (PV/Br) as a new high-performance electrolyte. The symmetric PV/Br redox EC produces a specific energy of 48.

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We report a new electrochemical capacitor with an aqueous KI-KOH electrolyte that exhibits a higher specific energy and power than the state-of-the-art nonaqueous electrochemical capacitors. In addition to electrical double layer capacitance, redox reactions in this device contribute to charge storage at both positive and negative electrodes via a catholyte of IOx-/I- couple and a redox couple of H2O/Had, respectively. Here, we, for the first time, report utilizing IOx-/I- redox couple for the positive electrode, which pins the positive electrode potential to be 0.

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Electrochemical double-layer capacitors exhibit high power and long cycle life but have low specific energy compared with batteries, limiting applications. Redox-enhanced capacitors increase specific energy by using redox-active electrolytes that are oxidized at the positive electrode and reduced at the negative electrode during charging. Here we report characteristics of several redox electrolytes to illustrate operational/self-discharge mechanisms and the design rules for high performance.

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A novel nanostructured catalyst with an ultra-thin porous shell obtained from the thermal decomposition of an aluminium alkoxide film deposited by molecular layer deposition for size-selective reactions was developed. The molecular sieving capability of the porous metal oxide films was verified by examining the liquid-phase hydrogenation of n-hexene versus cis-cyclooctene.

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Solar thermal water-splitting (STWS) cycles have long been recognized as a desirable means of generating hydrogen gas (H2) from water and sunlight. Two-step, metal oxide-based STWS cycles generate H2 by sequential high-temperature reduction and water reoxidation of a metal oxide. The temperature swings between reduction and oxidation steps long thought necessary for STWS have stifled STWS's overall efficiency because of thermal and time losses that occur during the frequent heating and cooling of the metal oxide.

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