Scientists reveal how to avoid defects in promising zinc batteries

Environmental solutions to the global climate crisis have created significant demand for high-capacity, reliable and low-cost energy storage. Metal anodes, including lithium, sodium, zinc or magnesium, are promising materials for high energy density batteries because they have a higher capacity of storage than conventional anodes, such as graphite, and are more energy dense.

Among the metal anodes, zinc negative electrodes stand out due to their abundance in nature, low cost, high capacity and compatibility with aqueous electrolytes, which are more environmentally friendly and safer than organic electrolytes.

However, aqueous zinc-metal batteries (AZMB) tend to form dendrites during cycling, which can lead to short circuits and safety hazards. This is due to the complex ion transport at the electrode interface, which disrupts the deposition of zinc.

Now a team from Oxford University, University College London (UCL), and the ESRF have joined forces to study zinc electrodes with and without a special commercial coating called LAPONITE.   Guanjie He, professor at the department of Chemistry at UCL and co-corresponding author of this study, explains: “Surface modification plays a vital role in developing Zn battery systems, and the LAPONITE solution could potentially regulate ion movement. This new coating technology can help reduce harmful dendrite growth and extend battery lifespan.” Yuhang Dai, researcher at ZERO Institute at University of Oxford, adds: “It is essential to understand how the LAPONITE coating actually prevent uneven zinc deposition at the interface – knowledge that guides the design of next-generation Zn systems”.

The team used high-resolution, non-destructive X-ray tomography at beamline ID19 to look inside zinc electrodes during charging and discharging, in electrodes with and without the Laponite coating. ID19 recently started to offer high-resolution microtomography in a rapid access manner, allowing for quick access for highly relevant topics to scan large batches of samples with established setups. Alexander Rack, scientist in charge of the beamline explains the advantages of the new developments at the ESRF:  “Thanks to the upgraded machine, we can offer a rapid X-ray tool that enables users to examine their emerging battery system in real-time. This helps establish the relationship between materials synthesis, structural evolution, and the Zn system performance. It is impressive how our first fast access users managed to convert the results so quickly into a high impact publication. ”

The results showed that the coating guides the zinc to grow uniformly and vertically, which prevents the “ion flux vortex” that leads to battery failure. These analysis were supported by computational fluid dynamics simulations.

ID19 for highly dynamic phenomena in batteries

Professor Paul Shearing, Director of ZERO Institute at The University of Oxford, and co-corresponding author of the study, says: “While improving today’s Li-ion technology remains crucial, it is equally important to pioneer new battery systems, such as Zn system that can meet future demands for safer, more sustainable, and higher-performance energy storage. We have been collaborating with ID19 for over a decade, and their advanced X-ray techniques have been instrumental in supporting us in many ways, from understanding fundamental degradation mechanisms, to improving electrode manufacturing, to enhancing battery safety.”

Wenjia Du, researcher of Oxford Martin School, and author of this study, adds: “We have been applying high-speed synchrotron X-ray imaging at ID19 to probe highly dynamic phenomena in various battery systems – from tracking dendritic growth to observing particle dissolution and crack propagation. Such information is almost impossible to obtain in a conventional laboratory, so the ESRF provides critical insights that accelerate the battery development. This study clearly demonstrated how advanced X-ray technique can support coating development for Zn battery”.

The publication shows that practical application is possible in the future. The pouch cell runs more than 100 cycles, with a maximum capacity of ca. 3.2 Ah. Whilst Li-ion technology still plays a dominant role, other chemistries (i.e., Zn, Li-S) also have their unique roles in supporting energy transition and are being rapidly developed and commercialised, and the researchers  expect to see zinc-based batteries in the field. In this respect, the authors have established a start-up that scaled up from laboratory research, focusing on Zn battery production and commercialisation.

Reference:

Dai, Y., Du, W., Dong, H. et al. Mitigating ion flux vortex enables reversible zinc electrodeposition. Nat Commun 16, 7312 (2025). https://doi.org/10.1038/s41467-025-62470-x

Text by Montserrat Capellas Espuny

Top image: Regions of interest demonstrating the mean curvature distribution of bare Zn (a) and LAPO@Zn (b). Credits: Dai, Y, et al, Nature Communications 16, 7312 (2025).