Impact of separator's solid‐phase ion conductivity parameter on convection battery performance and modeling

Abstract

A solid‐phase ion conductivity parameter has been added to the separator of a porous electrode theory description of a convection battery performance to increase the accuracy of this model. With the addition of the ion conductivity parameter, the variances between the model and experimental data have been reduced by 80–85% in both the convection cell and the diffusion cell. The parameter is fundamentally consistent with solid‐phase mechanisms by which ions can transport through separators in parallel with liquid‐phase transport, and the improved modeling results substantiate the importance of solid or surface ion transport mechanisms at high current fluxes. Modeling was supplemented with dimensionless analysis to lump fundamental parameters that are inherently coupled in the underlying equations. From this analysis, a global parameter has been developed describing the ratio of convective charge transfer to diffusive charge transfer that characterizes the transition from diffusive to convective cell behavior. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3784–3791, 2014

Improved Electrochemical Performance of Alkaline Batteries Using Quaternary Ammonia Polysulfone-Functionalized Separators

“…The ideas presented here can be applied to both CFBs and sandwich diffusion batteries (SDBs; Figure ), in which both use a solid substrate that can be functionalized with ion-containing polymers. Eventually, the mechanism of the improvement in ion conduction in alkaline media by QA groups substituted on PSF chains is introduced, which agrees with our previous theoretical work. , …”

“…Considering all of the research carried out on membrane synthesis, one can question the cost and mechanical properties of ion-exchange membranes, while using a porous separator as a substrate for ion-exchange polyelectrolytes (IEPEs) maintains the mechanical integrity and minimizes the casting expenses, resulting in a more economical and practical approach in industry. Coating the filter paper (FP) surface with ion-exchange polymers is an extendable concept to the majority of battery chemistries, the efficiency of which was proven in our theoretical work on LiFePO 4 batteries concerning the impact of the separator’s solid-phase ion-conductivity parameter on the accuracy of porous electrode theory; by considering the solid-phase transport alongside the liquid-phase transport in the separator, the variances between the model and experimental data were reduced by 80–85%, and the voltage and specific capacity were increased in both convection and diffusion cells at high current fluxes …”

“…Coating the filter paper (FP) surface with ionexchange polymers is an extendable concept to the majority of battery chemistries, the efficiency of which was proven in our theoretical work on LiFePO 4 batteries concerning the impact of the separator's solid-phase ion-conductivity parameter on the accuracy of porous electrode theory; by considering the solidphase transport alongside the liquid-phase transport in the separator, the variances between the model and experimental data were reduced by 80−85%, and the voltage and specific capacity were increased in both convection and diffusion cells at high current fluxes. 17 The improvement of the zinc−alkaline battery performance through the use of highly conductive materials and PE-coated FPs is described in this paper. Moreover, this work demonstrates the significance of solid-phase transport mechanisms in the separator through experimental evaluation.…”

“…Eventually, the mechanism of the improvement in ion conduction in alkaline media by QA groups substituted on PSF chains is introduced, which agrees with our previous theoretical work. 17,18…”

Experimental Validation of the Elimination of Dendrite Short-Circuit Failure in Secondary Lithium-Metal Convection Cell Batteries

“…A new technology, called the convection cell, has previously been shown to improve performance over diffusion mode lithium-ion cells has the capability of preventing dendritic growth within the separator of lithium-metal batteries without the use of additional materials or additives but requiring only flow. [33][34][35][36][37] By flowing electrolyte through positive and negative electrodes in series, standard diffusion concentration profiles can be altered to reduce the thermodynamic favorability of dendritic growth from electrode surface into the separator. Thermodynamic favorability is directly influenced by electrochemical potential of the species involved, as explained further in the Results and Discussion section of this paper.…”