# Shanghai University: MnO2 slurry lifts manganese flow battery capacity to 156.2 Ah/L in lab tests

- Published: 2026-11-05 23:52 UTC
- Section: Power & Energy › Batteries
- Tags: manganese flow battery, semi-solid slurry electrolyte, MnO2 slurry, common-ion effect, specific capacity, Mn3+/Mn2+, redox flow battery, grid-scale storage, Nano-Micro Letters
- URL: https://realtech.media/news/rt-33ab1c039db9c2e78961b4d7_shanghai_university_mno2/

**Researchers added solid MnO2 to a manganese electrolyte and reached 3.76 M soluble manganese, a 409% capacity gain over MnSO4 electrolytes, in laboratory cells.**

![Shanghai University: MnO2 slurry lifts manganese flow battery capacity to 156.2 Ah/L in lab tests](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/4e672e87e2813671.webp)
*Interesting Engineering*

Researchers at Shanghai University have developed a semi-solid slurry electrolyte for manganese redox flow batteries with a specific capacity of 156.2 Ah per litre of catholyte. According to the study in Nano-Micro Letters, this is 409% above reported MnSO4-based electrolytes [1]. The results were obtained in laboratory cells.

## Solubility limit of manganese electrolytes

In conventional H2SO4 electrolytes, the common-ion effect of SO4 2− limits the solubility of MnSO4 to 1 M or less, which keeps the specific capacity of manganese flow batteries low [1]. Semi-solid MnO2 batteries are expected to raise capacity, but their slow reaction kinetics limited earlier cells to current densities of 1 mA cm−2 or below [1].

The authors introduced a high concentration of MnO2 into the conventional manganese electrolyte. The MnO2/Mn2+ electrochemical reaction circumvents the common-ion effect: a slurry with 4 M MnO2 gave a soluble manganese concentration of 3.76 M [1].

## Higher current density and cycling

During the second charging cycle, reverse disproportionation of the electrolytic MnO2 shifts the redox mechanism from the solid MnO2/Mn2+ couple to the dissolved Mn3+/Mn2+ pair, the authors report. This raises the discharge voltage and allows stable operation at 30 mA cm−2, 30 times higher than in reported Mn-based semi-solid flow batteries [1]. Capacity stayed above 151 Ah per litre at the same slurry concentration at this current density, with energy efficiency above 71%.

In a separate test, a cell with a 1 M MnO2 slurry completed 100 charge-discharge cycles with about 99% Coulombic efficiency and 76% energy efficiency. The researchers note that further work is needed to reduce capacity loss caused by manganese crossover and particle buildup.

The authors present the approach as a design strategy for semi-solid slurry electrolytes that could improve the applicability of flow batteries in grid-scale storage of renewable energy [1].

## Sources

1. [Nano-Micro Letters](https://doi.org/10.1007/s40820-026-02349-8)
2. [Interesting Engineering](https://interestingengineering.com/energy/chinese-team-manganese-batteries-capacity-boost)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-33ab1c039db9c2e78961b4d7_shanghai_university_mno2/