# Toward the Development of a Uranium‐Based Redox‐Flow Battery

## TL;DR

Researchers developed a new type of battery using uranium compounds that could be used for large-scale energy storage.

## Contribution

The first all-uranium-based redox-flow battery is demonstrated with a 2.2 V cell voltage and potential for scalable energy storage.

## Key findings

- A uranium-based electrochemical cell achieved a cell voltage of 2.2 V using [UIV/V(tBuacac)4]0/+ and [UIII/IV(N(SiMe3)2)4]−/0 complexes.
- The system has a projected energy density of 0.357 Wh kg–1 and uses uranium compounds with high solubility and stability.
- The battery is suitable for underground energy storage systems due to its tolerance for radioactivity and weight.

## Abstract

An all‐uranium‐based electrochemical cell consisting of simple [UIV/V(
tBuacac)4]0/+ and [UIII/IV(N(SiMe3)2)4]−/0 complexes as anolyte and catholyte species was constructed with a cell voltage of 2.2 V. The [UIV(
tBuacac)4] (1) and [UIV(N(SiMe3)2)4] (2) complexes have favorable properties for redox‐flow‐battery applications, including reversible redox chemistry, relatively high stability toward electrochemical cycling, and high solubility in common organic solvents. The [UIII/IV(N(SiMe3)2)4]−/0 complexes were first isolated and characterized by Schelter et al., and performed well in electrochemical studies due to the comparably low reduction potential of −2.05 V vs. Fc/Fc+ to the reduced uranium(III) species. Treatment of conveniently accessible 1 with AgSbF6 allowed the isolation of [UV(
tBuacac)4][SbF6] (3), which is the active catholyte species generated during cell charging. Galvanostatic cycling with charging and discharging at currents of 20 and 5 μA, respectively, was performed in a two‐compartment static H‐cell with high‐surface‐area carbon fiber electrodes to achieve a potential of 2.2 V. The success of this 1||2 cell‐provides a promising entry point to a potential future class of uranium‐based, nonaqueous redox‐flow‐battery electrolytes, not for use in personal devices but incorporated into underground energy storage systems, where weight and radioactivity levels are not an issue and where this abundant waste material could find new application.

The first all‐uranium‐based electrochemical cell has been realized using simple [UIV/V(tBuacac)4]0/+ and [UIII/IV(N(SiMe3)2)4]–/0 complexes, readily available in convenient, scalable syntheses, as anolyte and catholyte couples. Operating at a cell potential of 2.2 V with a projected energy density of 0.357 Wh kg–1, this system establishes a foundation for the development of uranium‐based redox‐flow batteries.© 2026 WILEY‐VCH GmbH