Development of an all aqueous thermally regenerative ammonia battery using Cu(I,II) redox reactions
Open Access
- Author:
- Springer, Renaldo
- Graduate Program:
- Energy and Mineral Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 21, 2022
- Committee Members:
- Mort D Webster, Program Head/Chair
Derek M Hall, Thesis Advisor/Co-Advisor
Serguei Lvov, Committee Member
Christopher A Gorski, Committee Member - Keywords:
- Thermally Regenerative ammonia battery
TRAB
energy storage
all aqueous TRAB - Abstract:
- Thermally regenerative ammonia batteries (TRABs) are electrochemical energy conversion devices that convert low-grade waste heat into electrical power. The formation of metal amine complexes during cell discharge, resulting from the addition of ammonia to the anolyte, generates electrical power. After cell discharge, the ammonia is recovered from the spent anolyte by distillation with low-grade waste heat and re-added to the former cathode chamber, repeating the process. To date, TRABs suffer from poor performance due to their reliance on dissolution and deposition redox reactions with transition metals. Here, we present a new TRAB chemistry utilizing Cu(I/II) redox reactions; in conjunction with ligands to stabilize the aqueous copper ions, thereby creating the first reported all-aqueous TRAB. Rotating disc electrode studies were conducted to evaluate thermodynamic and kinetic parameters of prospective anolyte and catholyte chemistries. The use of NH3(aq) and Br-(aq) ligands resulted in a cell potential difference of 695 ± 2 mV with rate constants of 101 ± 5 µm s-1 and 819 ± 236 µm s-1, respectively. Single cell tests achieved power densities up to 350 W m-2 which are the highest reported for single metal TRABs at 25 °C. Coulombic efficiencies exceeded 90% and their energy storage densities were two to four times of those reported for alternative TRAB chemistries.