Revisiting poly(vinyl chloride) reactivity in the context of chemical recycling
An overview of PVC functionalization through the lens of chemical recycling.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Engineering topics
Neyhouse, Bertrand J.
Publications and source records attributed to Neyhouse, Bertrand J..
A Method for Quantifying Crossover in Redox Flow Cells through Compositionally Unbalanced Symmetric Cell Cycling
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Neyhouse, Bertrand J.↗
Characterizing the Impact of Oligomerization on Redox Flow Cell Performance
Abstract Redox flow batteries (RFBs) are hindered by complex failure modes, particularly crossover through the membrane, resulting in capacity fade and reduced cycling efficiencies. Redox‐active oligomers (RAOs) have recently been proposed for mitigating this phenomenon while maintaining sufficient transport properties; however, to date, few studies have quantified how the chemical and electrochemical properties of RAOs influence their performance in redox flow cells. Here, we demonstrate that oligomeric derivatives of 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) exhibit lower diffusivities than the monomeric species but retain facile charge transfer characteristics. The size‐dependent variations in mass transport rates directly translate to differences in flow cell polarization and symmetric cycling performance. Post‐mortem analyses reveal that oligomerization does not meaningfully alter decay processes as evinced by similar capacity fade across all species. Broadly, these findings corroborate and extend upon previously developed relationships between molecular size, electrochemical properties, and flow cell performance.
36 MATERIALS SCIENCE↗
Concentration‐dependent Cycling of Phenothiazine‐based Electrolytes in Nonaqueous Redox Flow Cells
Increasing redox-active species concentrations can improve viability for organic redox flow batteries by enabling higher energy densities, but the required concentrated solutions can become viscous and less conductive, leading to inefficient electrochemical cycling and low material utilization at higher current densities. To better understand these tradeoffs in a model system, we study a highly soluble and stable redox-active couple, N-(2-(2-methoxyethoxy)ethyl)phenothiazine (MEEPT), and its bis(trifluoromethanesulfonyl)imide radical cation salt (MEEPT-TFSI). We measure the physicochemical properties of electrolytes containing 0.2–1 M active species and connect these to symmetric cell cycling behavior, achieving robust cycling performance. Specifically, for a 1 M electrolyte concentration, we demonstrate 94% materials utilization, 89% capacity retention, and 99.8% average coulombic efficiency over 435 h (100 full cycles). This demonstration helps to establish potential for high-performing, concentrated nonaqueous electrolytes and highlights possible failure modes in such systems.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗