How Zinc Batteries Are Defying Limits

Batteries don’t last forever — whether they’re in your phone, EV, or laptop. Extending battery life is a major engineering challenge, but what if there was a battery that could last over 100,000 cycles? A battery that could go an entire lifetime with little to no degradation? Imagine guaranteeing performance not just for years — but decades. Well, a team in Germany might have just made it a reality, turning a notoriously short-lived battery into one of the longest-lasting ever.

How did scientists pull this off? And more importantly, when can we start seeing these batteries in our phones and EVs?

The Revolutionary Battery

This isn’t just a battery; it’s a lifetime commitment … and one with an extraordinary secret. Developed by the Technical University of Munich (or TUM), it can last for 100,000 cycles.¹ That kind of durability could change everything. For example, Elon Musk has said Tesla car batteries should last for 300,000 to 500,000 miles.² That’s roughly the distance you’d cover if you drove to the moon and back — three times. According to Tesla’s 2021 impact report, their batteries are designed to last the lifetime of a vehicle, which they estimate at around 150,000 to 200,000 miles.³ This figure is estimated from batteries lasting only a few thousand charge cycles.² Imagine what a battery lasting 100,000 cycles could mean for EVs, phones, laptops—you name it. Your EV might last so long, it’ll have vintage plates before you need a replacement.

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How is this even possible? It all starts here. You might be thinking, “Wait, does zinc really make good batteries?” And you’d be right: zinc does have potential. In fact, researchers once thought zinc-ion batteries (ZIBs) could replace lithium-ion batteries. The problem? Zinc batteries tend to have poor life spans due to a few big issues.

That’s where TUM made a breakthrough. They used an organic polymer called TpBD-2F. Don’t worry, I’ll explain what that is in a bit.¹ When they applied it to the anode of their zinc-ion battery, the results were nothing short of shocking.

Why Zinc?

To understand how TUM achieved this, we need to take a closer look at the material they’re using: zinc. Zinc might not get as much attention as lithium, but it has several key advantages that are sparking interest for batteries.

First, zinc is abundant and relatively cheap. It’s the 23rd most abundant element in the Earth’s crust, making it far easier and less expensive to source than lithium.⁴⁵ By contrast, lithium mining is highly concentrated in a few regions, and the refining process is mostly concentrated in in China, which houses 60% of the world’s lithium refining facilities.⁶⁷ The growing demand for lithium is expected to see the global market balloon from $26.88 billion in 2024 to $134.02 billion by 2032.⁸ As the demand for lithium balloons, zinc offers a much-needed “element” of surprise.

It’s not just about abundance, though. Zinc is also nontoxic, easy to recycle, and pairs well with water-based electrolytes, which are safer and less flammable than the organic solvents used in lithium-ion batteries.⁹ This makes zinc batteries an appealing option for applications like grid-scale energy storage, where safety is critical, and space isn’t as much of a concern. The recyclability and friendlier electrolytic solutions also make it a greener option.

The Challenges with Zinc

If zinc has so much going for it, why hasn’t it already replaced lithium in more applications? The answer lies in a set of stubborn challenges that have plagued zinc batteries for years.

First, there’s the issue of dendrites. These are tiny, spiky structures that form on the anode during charging and discharging. Zinc dendrites grow in layers, creating hexagonal platelets that stack into needle-like projections.¹⁰ Over time, these needles can grow large enough to puncture the battery’s separator, causing short circuits. Even worse, they can snap off during use, effectively removing zinc from the system and reducing the battery’s capacity. Think of the arms of a snowflake or ice crystalizing on your windshield; these are examples of dendritic growth. You can see that it can happen quickly, and once these grow and contact other conductors, the battery is shorted.

Then there’s the problem of corrosion and the hydrogen evolution reaction (HER). Think of the battery’s cathode as a fancy hotel designed to accommodate zinc ions as guests. During intercalation, zinc ions move into the cathode’s layers, checking into their “rooms.” The more ions the cathode can hold, the more energy the battery can store.

Zinc has a complicated relationship with water-based electrolytes. Hydroxide ions from the water tend to react with zinc, creating zinc hydroxide, a compound that acts like a rowdy party crasher, filling up all the hotel rooms and leaving no space for zinc ions.⁹¹¹¹² This means fewer ions can check in, reducing the battery’s charge capacity over time.

To make matters worse, HER generates hydrogen gas, which disrupts the ion flow and damages the structure of the hotel itself. It’s like having a gas leak in the building…it’s both bad for business and terrible for battery performance.

These issues — dendrites, corrosion, and HER — are the main reasons why zinc-ion batteries have traditionally had short lifespans, often limited to just a few thousand cycles. Solving these problems is no small task, but that’s exactly what TUM’s breakthrough aims to do.

TUM’s Breakthrough

The research team developed a 2D porous organic polymer called TpBD-2F to coat the zinc anode.¹³ While coatings aren’t new in battery research, this one stands out for its unique properties.

The polymer forms a protective film over the anode, but it’s not just a barrier. It has “built-in nanochannels” that allow zinc ions to pass through easily, ensuring the battery can charge and discharge efficiently.¹³ Its highly ordered crystalline structure acts like a superhighway, allowing ions to move quickly and reducing energy losses.¹

The polymer also helps zinc distribute evenly across the anode’s surface, preventing the clumping that leads to dendrite formation.¹³ It’s both zincophilic and hydrophobic, meaning it attracts zinc while repelling water. This dual property minimizes the HER effect, reducing corrosion and improving the battery’s overall stability.¹⁴

With this innovation, TUM has tackled three of zinc’s biggest challenges — dendrites, corrosion, and HER — all at once.

Overcoming the Drawbacks

As exciting as TUM’s breakthrough is, it doesn’t solve all of zinc’s challenges. One of the biggest limitations, like I mentioned before, is energy density. Zinc-ion batteries are less energy-dense than lithium-ion batteries, meaning they’re bulkier and heavier for the same amount of stored energy. This means you probably won’t have a zinc-ion powered EV any time soon, let alone a smartphone.¹⁵ A zinc-powered iPhone would probably need to come with its own iBackpack.

However, zinc batteries are ideal for stationary applications, where space and weight aren’t as big of an issue. In fact, zinc-based batteries have already started making an impact in grid-scale energy storage.

One of the most significant advantages of zinc batteries in stationary applications is their safety profile. Even though it’s rare, lithium-ion batteries are susceptible to thermal runaway: a chain reaction that can cause fires or explosions under certain conditions. Zinc batteries, especially those using aqueous electrolytes, eliminate this risk. This makes them an excellent choice for large installations in populated areas or fire-prone regions, where safety concerns are paramount.

Zinc batteries also address another growing concern: sustainability. Unlike lithium, which is extracted through environmentally damaging mining processes (although there are some new processes to address that), zinc is more abundant and easier to recycle. This makes it a more sustainable choice as demand for energy storage continues to grow. It also reduces the potential for bottlenecks in the supply chain, as much of the world’s current supply of lithium is mined in only a handful of countries.

An example of zinc’s potential is Eos Energy Enterprises. This company manufactures zinc halide batteries for large-scale energy storage, highlighting how zinc technology is already stepping up to the plate. While Eos’ batteries aren’t the same as TUM’s polymer-enhanced zinc-ion models, they’re an excellent example of how zinc can shine in stationary applications. Eos batteries are designed to be non-flammable, long-lasting, and eco-friendly.¹⁶

Eos has made significant strides in California, a state where wildfire risks make traditional lithium-ion batteries less appealing for large installations. The company recently expanded its California facility from 35 MWh to 60 MWh, thanks to partnerships with the California Energy Commission.¹⁷¹⁸ This facility plays a key role in meeting California’s renewable energy goals, as it provides safe and reliable storage for excess power from solar and wind with a greatly reduced chance of fire.

Springfield, Missouri, also recognized the potential of zinc-based storage. In late 2024, the city purchased 216 MWh of energy storage systems from Eos, aiming to stabilize the local grid and store renewable energy for peak demand.¹⁹ This project highlights how zinc batteries are already contributing to more sustainable energy infrastructure.

Of course, Eos isn’t without its challenges. Like many innovators in the energy space, the company faces financial and legal hurdles. Recent shareholder lawsuits and a reliance on troubled projects like Bridgelink Energy (which faced foreclosure) have raised questions about Eos’ ability to scale.²⁰ Despite these issues, the company’s work underscores how zinc-based batteries are carving out a niche in the real world and could see even greater adoption with advancements like TUM’s polymer.

The Future of Zinc Batteries

So, when can we expect to see TUM’s polymer-enhanced zinc-ion batteries in action? Right now, the technology is still in the lab, sitting at a Technology Readiness Level (TRL) of 4.²¹ That means it’s far from commercial deployment, but the results are promising enough to imagine real-world applications down the line.

One of the biggest hurdles for TUM’s technology will be scaling up production. Lab-based breakthroughs often face challenges when transitioning to mass production, especially when new materials or manufacturing processes are involved. However, if the polymer coating can be produced cost-effectively, it could unlock a new generation of batteries for diverse applications.

Looking forward, zinc-ion technology seems perfectly positioned to take on a larger role in grid-scale energy storage. The intermittent nature of renewable energy sources like solar and wind makes efficient storage a must. Zinc batteries, with their safety, durability, and lower cost, are well-suited for this role. By complementing lithium-ion batteries, they could help diversify the energy storage landscape and ensure more reliable grids worldwide.

What’s particularly exciting is that TUM’s polymer isn’t limited to zinc. According to the researchers, it could be applied to other metal anodes, including lithium, sodium, and aluminum.¹³ This opens up a wide range of possibilities for improving battery performance and durability across different technologies.

The benefits aren’t just technical, either. A 100,000-cycle battery isn’t only about saving money. It’s also about reducing waste and making the energy sector more sustainable. Long-lasting batteries mean fewer replacements and lower overall environmental impact, which aligns perfectly with the growing global emphasis on green energy. It’s also about winning the battle of consumer confidence, as battery anxiety in all forms is still a limiting factor for electrification.

As Eos has shown, zinc-based batteries are already proving their value in this niche. With innovations like TUM’s polymer pushing the boundaries, we may see even longer-lasting, higher-performance zinc batteries becoming a staple of the energy storage landscape.

The advancements happening today aren’t just about improving a single battery…they’re about reshaping the future of energy storage entirely. Whether it’s lithium, zinc, or something entirely new, we’re one step closer to a world powered by cleaner, safer, and more efficient technologies.