Simulating Discharge Curves of an All-Aqueous TRAB to Identify Pathways for Improving System Performance

Abstract

Thermally regenerative ammonia batteries (TRABs) are an emerging technology that use low temperature heat (T < 150 °C) to recharge a flow battery that produces electrical power on demand. The all-aqueous copper TRAB can provide high power densities and thermal energy efficiencies relative to other devices that harvest energy from waste heat, but its performance is adversely impacted by the crossover of undesired species through the membrane and lower cell voltages compared to conventional batteries. In this work, we developed a numerical model to simulate discharge curves while accounting for crossover inefficiencies without tracking all electrolyte species through the membrane. The model was able to successfully reproduce discharge curves across a diverse range of battery conditions using a single fitting parameter to account for decay of electrode standard potential due to species crossover with minimal error (< 5%). The model was then used to simulate different design scenarios to estimate changes in energy output from alterations to the aspects of the battery electrolyte chemistry. Results from this study are used to identify pathways for improving future TRAB designs with respect to energy capacity and cost-effectiveness of the technology.

Nitrogen and Sulfur Co-doped Biomass-Derived Porous Carbon Electrodes for Ultra-High-Performance All-Aqueous Thermally Regenerative Flow Batteries

“…Through the N and S co-doped into porous carbon materials, the high-performance electrode can be developed, characterized by the large specific surface area, low charge transfer resistance, and rich active sites. , Research on traditional TRB electrodes has primarily focused on improving the specific surface area and stability of metal electrodes to enhance the power generation performance. In all-aqueous TRB studies, more attention has been paid to the relationship between ATRB power density and energy density, as well as research on ion exchange membranes. , In the field of thermally regenerative batteries, there has been no research on nitrogen and sulfur co-doped carbon materials. Such porous carbon electrodes with co-doped properties hold promise for enhancing the power generation of ATRB, necessitating experimental and theoretical research for validation.…”