New Trick Tech Promises To Triple EV Range And Battery Life

Scientists at the Ulsan National Institute of Science and Technology (UNIST) in South Korea have developed a new gel type battery fluid, called a gel electrolyte. In lab tests, it could increase electric vehicle battery range by about 2.8 times and make the battery last almost three times longer. The idea is not to change the whole battery, but to change the liquid part inside it that carries charge between the positive and negative sides.

Why Pushing For More Range Damages Today’s EV Batteries

To get more range from the same size battery, carmakers are pushing lithium-ion cells to work at higher voltages, above roughly 4.4 volts. On paper, higher voltage means more energy in each cell. In reality, it creates a serious side effect in nickel rich battery packs.

At these higher voltages, the material on the positive side of the battery starts to release oxygen from its structure. That oxygen turns into very reactive oxygen-based chemicals, often called reactive oxygen species. These chemicals attack the normal liquid electrolyte and the positive electrode. Over time they can:

A. Damage the battery materials

B. Dissolve nickel from the cathode

C. Create gas inside the cell that makes it swell

D. Shorten the usable life of the pack

In one common high nickel battery type called NMC811, this oxygen release begins at around 4.3 to 4.4 volts. In types with less nickel such as NMC622 and NMC111, it starts higher, around 4.6 to 4.7 volts. This is one reason cell makers are cautious about pushing voltage too far.

How The New Gel Electrolyte Tries To Fix It

The UNIST team designed a gel like electrolyte made from two key ingredients: an organic molecule called anthracene and polymer chains that carry nitrile groups. Together they form a thicker, gel style electrolyte instead of a thin liquid.

Anthracene plays a double role. First, it sticks to unstable oxygen at the surface of the positive electrode so that oxygen does not escape and turn into reactive oxygen species. Second, if any of these reactive oxygen molecules do form, anthracene can capture and neutralise them before they attack the rest of the cell. The researchers describe this as a two-step protection system.

The nitrile groups in the polymer help in another way. At high voltage, nickel atoms in the cathode can dissolve and move around, which slowly ruins the structure of the electrode. The nitrile groups bond with nickel and help hold the structure together, reducing cracking and loss of capacity.

What The Lab Tests Showed

In tests at 4.5 volts, cells using the new gel electrolyte kept 81 percent of their original capacity even after 100 charge and discharge cycles. That is a strong result for this voltage range.

The team also measured gas build up by checking how much the test cells swelled. With the gel electrolyte, swelling was about 13 micrometres. With a normal electrolyte, swelling was around 85 micrometres. That is roughly six times more gas formation in the conventional setup. Less gas means less swelling, lower risk of failure and more stable performance over time.

Why This Matters For Future EVs

In conventional electrolytes, different side reactions happen at different states of charge. At lower charge levels, part of the solvent can change into another chemical on the cathode surface. At high charge levels, the reactive oxygen from the cathode can oxidise the solvent to form carbon dioxide, carbon monoxide and water. Over thousands of cycles this:

A. Eats away at the electrolyte

B. Creates resistive layers on the electrodes

C. Produces gas

D. Dissolves transition metals such as nickel

All of these effects are bad for long term battery health. The UNIST work shows that by designing the electrolyte to control oxygen behaviour, it may be possible to safely run higher voltage cells while cutting these side reactions.

The researchers say this approach could be useful for long range electric cars, lighter lithium-ion packs for aerospace and large energy storage systems that need long life and low maintenance. Their study, led by Professor Hyun Kon Song and published in Advanced Energy Materials, is still at the laboratory stage. There is no timeline yet for commercial use. The next steps are to show that this gel electrolyte can be made at scale and used in real world cells and packs that go into production EVs.

Via DOI