A New Breakthrough in EV Battery Longevity: How UNIST’s Gel Electrolyte Can Nearly Triple Lifespan

 When discussing the future of electric vehicles, most people immediately think of driving range. But there is another equally critical factor that shapes both performance and safety: battery lifespan.

As batteries age, capacity fades, internal resistance increases, driving range drops, and safety risks begin to rise. In high-voltage lithium-ion batteries, one of the most destructive triggers behind this aging is oxygen-induced degradation at the cathode–electrolyte interface.

A research team at the Ulsan National Institute of Science and Technology (UNIST) in South Korea has developed an impressive solution to this problem:

a semi-solid gel electrolyte capable of “trapping” reactive oxygen species, significantly slowing down degradation.

Laboratory results show that this new material can extend high-voltage battery life by up to 2.8 times and reduce cell swelling by nearly six-fold.

So, how does it work?

The Hidden Enemy in Lithium-Ion Batteries: Oxygen-Induced Aging

To achieve higher energy density, modern EVs increasingly rely on nickel-rich (Ni-rich) cathodes, such as NCM811. However, at high operating voltages, these cathodes trigger a sequence of harmful reactions:

1. Oxygen atoms in the cathode lattice form reactive oxygen species (ROS) such as singlet oxygen.

2. ROS aggressively attack the liquid electrolyte, breaking it down into gas and harmful by-products.

3. These by-products deteriorate the CEI/SEI layers and cause structural cracking at the cathode surface.

4. The result:

Rapid capacity fade

Rising internal resistance

Noticeable swelling

Increased risk of thermal runaway

While most research has traditionally focused on cathode coatings or electrolyte additives, the UNIST team approached the problem from a more fundamental angle:

controlling oxygen activity inside the electrolyte itself.

UNIST’s Solution: Anthracene-Functional Gel Electrolyte (An-PVA-CN)

The newly developed material—An-PVA-CN—is a semi-solid gel based on two key components:

1. Anthracene Functional Groups

An aromatic molecule composed of three fused benzene rings

Acts as a scavenger for reactive oxygen species

Captures singlet oxygen and other aggressive radicals, neutralizing them before they damage the electrolyte

2. Cyanoethyl-Modified Polyvinyl Alcohol (PVA-CN)

Forms a flexible but dense polymer network

Retains enough ionic conductivity for lithium transport

Restricts free diffusion of harmful oxygen species

Together, these features create an electrolyte that:

Suppresses oxygen dimerization and gas evolution

Traps oxygen species before they reach the cathode surface

Helps form a more stable cathode–electrolyte interface

UNIST published this work in Advanced Energy Materials under the title:

“Electrolyte-Driven Suppression of Oxygen Dimerization and Oxygen Evolution in High-Voltage Li-Ion Batteries.”

What Do the Results Show? Nearly Triple Lifetime, Massive Safety Gain

According to UNIST’s test data:

Conventional electrolytes:

Fall below 80% capacity after ~180 cycles

UNIST gel electrolyte:

Maintains ~81% capacity even after 500 cycles

This represents a 2.8× improvement in cycle life

Cell swelling is reduced to about one-sixth of the normal level

These improvements translate into:

Far more stable long-term performance

Reduced internal pressure

Lower risk of structural electrode damage

Better safety under aggressive fast-charging conditions

Why This Matters for Thermal Management

Although this breakthrough begins in the realm of materials science, it has direct implications for thermal management systems (TMS)—an area increasingly critical in EVs and electric buses.

1. Less Side-Reaction Heat → More Predictable Thermal Behavior

Reduced oxygen activity means fewer exothermic side reactions.

This leads to lower parasitic heat, making pack-level TMS behavior more stable, especially during fast charging.

2. Longer Cycle Life → New TMS Lifetime Targets

If cells last 2–3× longer, TMS designers can shift focus from extreme peak conditions toward long-duration stability and efficiency optimization.

3. Lower Thermal Runaway Risk

With reduced gas formation and slower degradation, the likelihood of a runaway “defective cell → local overheating → chain reaction” scenario drops.

4. Higher Energy Density → More Compact Packs

If high-voltage batteries can safely use this electrolyte chemistry, OEMs may design smaller and lighter packs, providing more packaging freedom for cooling ducts, heat exchangers, or structural integration.

Challenges: Why This Won’t Be in Mass Production Tomorrow

Despite its promise, several barriers must be overcome before automotive deployment:

1. Ionic Conductivity at Low Temperatures

Gel electrolytes typically conduct ions less efficiently than liquid ones, especially below −20 °C.

UNIST’s work mitigates this, but full EV-grade low-temperature data is still needed.

2. Manufacturing Scalability

The gel requires specific polymerization and infiltration steps that must work at gigafactory scale without slowing down production.

3. Compatibility With Existing Cells

Interactions with:

Ni-rich cathodes

Graphite–silicon anodes

Separators

Additive packages

must be validated over multi-year test cycles.

4. Cost and Supply Chain

High-purity anthracene derivatives and specialty polymers add cost.

Large-scale procurement and processing need to be justified by real-world advantages.