Low Salt Concentration Makes Zinc-ion Batteries Viable Compared with Li-ion

The discovery offers long-lasting performance and fast charging for zinc-ion batteries


Researchers from ETH Zurich have developed an environmentally friendly salt concentration for water-based zinc-ion batteries, which offers long-lasting performance and fast charging.

To store sustainably produced energy from sources like wind or sunlight, the world requires powerful and cost-effective batteries that can be utilized even in the absence of natural sources.

While lithium-ion batteries are commonly used to power smartphones and electric cars, they are costly due to the increasing global demand for lithium and are also prone to flammability issues.

A viable substitute for lithium-ion batteries is water-based zinc batteries which have the potential to offer promising benefits.

Although zinc batteries offer several advantages, durability remains a significant challenge.

Zinc, being abundant and inexpensive, with a well-established recycling infrastructure, can store a large amount of electricity. In addition, the use of water-based electrolytes in zinc batteries eliminates the need for highly flammable organic solvents as electrolyte fluids, making them a safer option.

Despite the many benefits of zinc batteries, engineers must overcome significant challenges during their development.

One such challenge is the formation of hydrogen gas when the battery is charged at high voltage, which causes a decrease in electrolyte fluid and battery performance, as well as dangerous pressure buildup.

Another issue is the development of dendrites, spikey deposits of zinc that can pierce through the battery during charging and can lead to short circuits.

The strategy of adding salts to the aqueous liquid electrolyte has been pursued by engineers to reduce the water content. However, this approach has its drawbacks.

The electrolyte fluid becomes thick and viscous, which slows down the charging and discharging processes significantly. Furthermore, most of the salts used in this method contain fluorine, which can be harmful and toxic to the environment.

To address this issue, Maria Lukatskaya, an Electrochemical Energy Systems Professor at ETH Zurich, collaborated with researchers from various institutions in the US and Switzerland to find the ideal salt concentration for water-based zinc-ion batteries.

Through a combination of experiments and computer simulations, they discovered that the optimal salt concentration is not the highest possible, as previously believed, but rather a relatively low concentration of five to ten water molecules per salt’s positive ion.

In March 2023, researchers at HZB found that solar cells made of metal halide perovskites achieve high efficiencies and can be produced from liquid inks with little energy input.

Researchers at Swansea University in Wales, United Kingdom, recently established a low-cost and scalable carbon ink formulation capable of unlocking the potential for manufacturing perovskite solar cells at scale.