Finding the Right TEMPO: Multi-Objective Virtual Screening and Experimental Validation of TEMPO Derivatives for Aqueous Redox Flow Battery Catholytes
5 affiliations
- 1Department of Virtual Material Design, Fraunhofer Institute for Algorithms and Scientific Computing, Schloss Birlinghoven 1, Sankt Augustin, 53754, Germany
- 2MODES, The Integrated Fuel and Science Center, RWTH Aachen University, Schinkelstraße 8, Aachen, 52062, Germany
- 3Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
- 4Innovation Centre in Digital Molecular Technologies, University of Cambridge, Lensfield Road, CB2 1EW, UK
- 5Cambridge Centre for Advanced Research and Education in Singapore (CARES Ltd), #05-05 CREATE Tower, 1 Create Way, 138602, Singapore
Abstract
We formulate the discovery of aqueous redox flow battery catholytes as a multi-objective optimization problem and introduce a virtual screening framework that simultaneously considers redox potential, chemical stability, and synthetic accessibility. Applied to a library of 182 TEMPO derivatives, the workflow identified a diverse set of high-ranking candidates, including the previously unexplored methyl carbamate-TEMPO (MC-TEMPO) and diethylamino-TEMPO (DEA-TEMPO). Furthermore, the screening revealed a moderate correlation between redox potential and predicted degradation resistance, indicating an intrinsic trade-off between these properties. For established TEMPO derivatives, the framework reproduced relative performance trends reported within independently studied series. Across the broader library, the highest-ranked candidates reflected a non-intuitive balance of electrochemical performance, stability, and synthetic accessibility rather than optimization of redox potential alone. MC-TEMPO and DEA-TEMPO were subsequently synthesized and experimentally characterized, providing a prospective test of the computational predictions. Cyclic voltammetry validated the redox potential predictions, with measured values closely matching the calculated values. During 130 h potentiostatic holds under sustained oxidizing conditions, MC-TEMPO showed no measurable electrochemical or molecular degradation, whereas DEA-TEMPO underwent a substituent-specific degradation pathway not captured by the initial screening model. Together, these results show that multi-objective catholyte discovery can prioritize molecules that would be overlooked by redox-potential optimization alone and provides a framework for the computationally guided design of organic redox flow battery catholytes.
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BibTeX
@misc{willimetz2026finding,
title = {{Finding the Right TEMPO: Multi-Objective Virtual Screening and Experimental Validation of TEMPO Derivatives for Aqueous Redox Flow Battery Catholytes}},
author = {Daniel Willimetz and Žak Ruben Šinkovec and Jan Hamaekers and Alexei Lapkin and Abhishek Khetan},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009596/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009596/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Finding the Right TEMPO: Multi-Objective Virtual Screening and Experimental Validation of TEMPO Derivatives for Aqueous Redox Flow Battery Catholytes
AU - Daniel Willimetz
AU - Žak Ruben Šinkovec
AU - Jan Hamaekers
AU - Alexei Lapkin
AU - Abhishek Khetan
PY - 2026
DA - 2026/09/29
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009596/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009596/v1
AB - We formulate the discovery of aqueous redox flow battery catholytes as a multi-objective optimization problem and introduce a virtual screening framework that simultaneously considers redox potential, chemical stability, and synthetic accessibility. Applied to a library of 182 TEMPO derivatives, the workflow identified a diverse set of high-ranking candidates, including the previously unexplored methyl carbamate-TEMPO (MC-TEMPO) and diethylamino-TEMPO (DEA-TEMPO). Furthermore, the screening revealed a moderate correlation between redox potential and predicted degradation resistance, indicating an intrinsic trade-off between these properties. For established TEMPO derivatives, the framework reproduced relative performance trends reported within independently studied series. Across the broader library, the highest-ranked candidates reflected a non-intuitive balance of electrochemical performance, stability, and synthetic accessibility rather than optimization of redox potential alone. MC-TEMPO and DEA-TEMPO were subsequently synthesized and experimentally characterized, providing a prospective test of the computational predictions. Cyclic voltammetry validated the redox potential predictions, with measured values closely matching the calculated values. During 130 h potentiostatic holds under sustained oxidizing conditions, MC-TEMPO showed no measurable electrochemical or molecular degradation, whereas DEA-TEMPO underwent a substituent-specific degradation pathway not captured by the initial screening model. Together, these results show that multi-objective catholyte discovery can prioritize molecules that would be overlooked by redox-potential optimization alone and provides a framework for the computationally guided design of organic redox flow battery catholytes.
ER -