New Electrolyte Additive Brings Zinc Batteries Closer to Safer Energy Storage

Aqueous zinc-ion batteries, commonly known as AZIBs, are attracting attention because they use water-based electrolytes instead of flammable organic solvents found in many lithium-ion batteries.

Rechargeable batteries are at the centre of the global shift toward cleaner energy, yet many of the technologies that power homes, industries and electric systems still depend on materials that are expensive, difficult to source or carry safety concerns. Scientists are now exploring alternative battery chemistries that can deliver reliable performance without those drawbacks, and aqueous zinc-ion batteries are emerging as one of the most promising options for large-scale energy storage. A team of researchers from the Institute of Nano Science and Technology (INST), Mohali, has now developed a new electrolyte additive that could significantly improve the performance and lifespan of these batteries while keeping them safe and affordable.

A Smarter Way to Improve Battery Performance

Aqueous zinc-ion batteries, commonly known as AZIBs, are attracting attention because they use water-based electrolytes instead of flammable organic solvents found in many lithium-ion batteries. This makes them inherently safer while also reducing manufacturing costs and environmental concerns. Despite these advantages, widespread commercial use has remained difficult because zinc metal anodes often develop needle-like structures called dendrites during repeated charging and discharging. These formations reduce battery efficiency, shorten operating life and may eventually cause internal failures. Zinc anodes also suffer from corrosion and unwanted hydrogen evolution reactions, both of which steadily weaken battery performance.

Instead of redesigning expensive battery materials, the INST researchers focused on improving the electrochemical environment where these reactions take place. Their work introduces a specially designed electrolyte additive known as 1,3-bis (1,3-dicarboxypropyl)-1H-imidazole-3-ium chloride (BDIM), which carefully controls reactions occurring at the zinc surface. This practical approach offers an easier pathway for improving battery performance without significantly increasing production costs, making it attractive for future large-scale manufacturing.

The research was led by Dr. Ramendra Sundar Dey, Scientist E at INST Mohali, and has been published in the journal ACS Electrochemistry.

New Molecule Protects the Zinc Surface

The newly developed BDIM additive contains multiple oxygen and nitrogen donor sites that naturally interact with zinc metal. During battery operation, the additive selectively adsorbs onto the negatively charged zinc surface, positioning itself inside the Inner Helmholtz Plane, an extremely important region where electrochemical reactions occur.

By occupying this space, BDIM effectively pushes water molecules away from the zinc surface. Since water molecules are responsible for triggering several undesirable chemical reactions, their displacement greatly reduces hydrogen evolution, corrosion and other side reactions that gradually damage the battery. The additive also suppresses the formation of zinc dendrites, allowing zinc to deposit more evenly across the electrode surface during repeated charging cycles.

This controlled deposition creates a smoother and more stable zinc layer, helping maintain battery performance over extended periods of use. Better surface stability also improves charging efficiency while reducing the degradation that typically limits the operational life of rechargeable zinc batteries. Because the additive works directly at the battery interface instead of altering the core battery design, the solution remains both scalable and economically attractive for commercial applications.

To understand exactly how BDIM influences zinc deposition, the research team combined a specially fabricated ultramicroelectrode (UME) with fast-scan cyclic voltammetry (FSCV), creating a highly sensitive experimental platform capable of observing electrochemical processes in remarkable detail.

Advanced Testing Reveals Cleaner Electrochemical Reactions

The ultramicroelectrode used in the study measures less than 50 micrometres in size, allowing scientists to observe electrochemical behaviour that cannot easily be detected using conventional electrodes. At this microscopic scale, diffusion changes from a simple linear pattern to a radial or hemispherical movement, making it possible to perform measurements at much higher scan rates while capturing subtle changes occurring on the zinc surface.

Fast-scan cyclic voltammetry complemented these measurements by tracking how charge transfer and mass transfer behaved when the BDIM additive was introduced into the electrolyte. The experiments revealed that the additive shifted the charge-transfer process toward lower scan rates, providing direct evidence of its influence on zinc deposition mechanisms.

These detailed observations gave researchers a much clearer understanding of how zinc grows during battery operation and how carefully designed electrolyte additives can reshape that process. Such knowledge could support the development of even more advanced electrolyte systems for future rechargeable batteries.

The implications of this research extend well beyond laboratory testing. Improved aqueous zinc-ion batteries could become valuable energy storage solutions for renewable power installations, electricity grids and backup power systems where safety, durability and affordability remain essential requirements. Longer-lasting batteries would also reduce maintenance costs while improving the reliability of energy infrastructure that supports solar and wind power generation.

As countries continue investing in cleaner electricity systems, innovations such as the BDIM electrolyte additive demonstrate how relatively small changes in battery chemistry can produce substantial improvements in performance. With safer operation, enhanced cycling stability and lower degradation, this technology offers a promising step toward making rechargeable zinc batteries a practical solution for large-scale sustainable energy storage in the years ahead.