Fudan Team's Flowing Zinc Slurry Battery Runs 5,128 Hours at 99.94% Coulombic Efficiency
Fudan University researchers built a flow battery using circulating zinc slurry instead of a fixed electrode, retaining 81.1% capacity after 5,500 cycles.
Overview
Researchers at Fudan University have built a flow battery that replaces the conventional fixed zinc electrode with a circulating zinc-based slurry, according to a paper titled “Flowing zinc slurry for long-duration energy storage” published in Nature Energy. In testing, the design achieved a Coulombic efficiency of 99.94% and ran continuously for 5,128 hours, with full cells retaining 81.1% of their capacity after 5,500 charge-discharge cycles.
What We Know
The work is led by corresponding author Fei Wang of Fudan University, with co-authors affiliated with the Dalian Institute of Chemical Physics at the Chinese Academy of Sciences. The paper was published on 24 June 2026.
In a conventional zinc battery, zinc metal sits as a fixed electrode that gradually degrades from repeated plating and stripping during charge cycles. The Fudan team’s approach instead disperses nanoscale zinc particles in a conductive network and pumps them through the cell as a slurry, where they undergo reversible zinc/Zn2+ redox conversion. Wang described the underlying goal in comments to Tech Xplore: “Our work emerged from our long-standing interest in improving the reversibility of Zn metal electrodes through electrolyte and interface engineering.”
Wang explained the motivation for moving away from a fixed electrode: “While Zn is an attractive candidate for large-scale energy storage because of its abundance, low cost and high volumetric capacity, conventional Zn electrodes suffer from interfacial degradation during repeated cycling,” Wang told Tech Xplore. The slurry design is meant to address that degradation directly: “A flowing Zn slurry battery specifically stores energy by replacing the conventional fixed Zn metal electrode with a circulating Zn-based slurry,” Wang said.
The full-cell durability figures — 81.1% capacity retained after 5,500 cycles — were measured in cells paired with a manganese dioxide electrode, according to the Nature Energy paper and corroborated by Tech Xplore’s reporting on the same figures.
As with other flow-battery architectures, the design decouples energy-storage capacity from power delivery: capacity can in principle be scaled by adding more slurry to external tanks without redesigning the electrochemical cell itself, a structural feature Interesting Engineering linked to the technology’s intended use for storing intermittent solar and wind power.
What We Don’t Know
The results reported so far come from laboratory-scale cells; the paper does not describe deployment at grid scale, and Wang was direct about the work ahead: “Our future research will focus on translating the flowing Zn slurry concept from a laboratory-scale demonstration toward practical long-duration energy storage systems,” Wang told Tech Xplore. Cost figures, manufacturing timelines, and any plans for pilot-scale installations have not been disclosed.
Analysis
Long-duration storage has become a crowded research area as grid operators look for alternatives to lithium-ion batteries, whose four-hour typical discharge window doesn’t match the multi-day storage needed to firm up intermittent solar and wind generation. The Nature Energy paper frames the challenge squarely in its opening line: “Long-duration energy storage is critical for integrating renewable energy, yet few technologies simultaneously achieve low cost, long cycle life and high safety,” according to the paper. Zinc-based chemistries are one of several approaches — alongside sodium-ion, iron-air, and vanadium flow batteries — being pursued because zinc is abundant and inexpensive compared with lithium or vanadium. The Fudan result adds a data point to that broader push, though as with any single lab result, replication at larger scale and independent verification of cycle life will determine whether the flowing-slurry approach moves beyond a laboratory demonstration.