Invented by Bae; Woojin, Kim; Soojin, Kim; Seulwoo, Moon; Jongseok, Park; Jongseok

Understanding how batteries work isn’t just for scientists anymore. We all want our phones, cars, and gadgets to last longer and be safer. Today, we’re looking at a new patent application for a special gel polymer electrolyte that could change how lithium batteries perform. Let’s break down what this invention means for the market, how it stands out from what came before, and what makes it truly special.

Background and Market Context

Everywhere you look, batteries are powering our lives. They are in our phones, laptops, electric cars, and even in big energy storage systems for homes and businesses. But as much as we love the freedom batteries bring, they come with problems—especially lithium batteries. The biggest worries? Safety, battery life, and how much energy they can store.

Most lithium batteries today use a liquid inside called a liquid electrolyte. This liquid helps lithium ions move between the battery’s positive and negative sides when charging and using the battery. But these liquids can catch fire if the battery is damaged or overheats. That’s why you sometimes hear about phones or cars catching fire. On top of that, batteries can lose power as they are used over and over, and sometimes they just don’t last as long as we wish.

Researchers and companies have been working hard to find new ways to make lithium batteries safer and to last longer. One big idea is to switch from liquid electrolytes to a gel or solid material. Gels can hold the liquid in place, making it less likely to leak or catch fire. But, making a gel that allows lithium ions to move easily—so the battery works well—has been tough. Many gels slow down the lithium ions, so the battery doesn’t work as well as before.

This new patent application comes at a time when the world is hungry for better batteries. Electric vehicles are everywhere. Renewable energy is growing fast, and we need to store that energy cheaply and safely. The market wants batteries that are safe, last for years, and can quickly deliver a lot of power. This invention aims to deliver just that by introducing a new kind of gel polymer electrolyte for lithium batteries.

Scientific Rationale and Prior Art

Before we jump into what’s new here, let’s see how battery electrolytes have worked up until now. Most lithium-ion batteries use a liquid electrolyte made from a lithium salt dissolved in an organic solvent. This setup lets lithium ions move back and forth during charging and use. It works well, but the liquid can leak, dry out, or even cause fires.

To tackle these problems, scientists have tried solid and gel electrolytes. Solid electrolytes can be very safe but often don’t let lithium ions move fast enough. Gel polymer electrolytes, or GPEs, try to give us the best of both worlds. They’re made by trapping a liquid electrolyte inside a crosslinked polymer matrix. This means the liquid can’t spill out, but ions can still move. However, many GPEs have had trouble matching the performance of liquid electrolytes. Sometimes, the gel is too thick and blocks the lithium ions, or it doesn’t stick well to the other battery parts.

Earlier solutions used simple polymers, like poly(ethylene oxide) or poly(acrylonitrile). These were easy to make but often led to high resistance (the battery couldn’t deliver power quickly) or made the battery age faster. Some researchers added more complex chemicals to improve the gel’s strength or help ions move faster, but this usually made the battery harder or more expensive to make.

Another issue was the “solid electrolyte interphase” or SEI—the thin layer that forms inside batteries during use. A good SEI keeps the battery healthy and helps it last longer. Some gels made this layer weak, leading to faster aging or even dangerous lithium dendrites (tiny spikes that can short out the battery).

Over the past few years, patents and research have aimed to find better combinations of polymers, lithium salts, and solvents. Some tried using special salts, like lithium difluoro(oxalato)borate (LiDFOB) or lithium tetrafluoroborate (LiBF4), to make a better SEI and improve battery life. Others experimented with new monomers (the building blocks of polymers) to make the gel tougher or help ions move more easily.

But most earlier inventions struggled to get everything just right: high safety, long life, fast power delivery, and easy manufacturing. Many gels were too stiff, too weak, or just didn’t let ions move well enough. This new patent application builds on all that past work and brings together new chemistry to solve these old problems.

Invention Description and Key Innovations

This invention introduces a gel polymer electrolyte that is both tough and flexible, letting lithium ions move easily so the battery can deliver power quickly and last a long time. Here’s how it works in simple terms:

The new gel is made from two types of special building blocks, called monomers. The first is a multifunctional acrylic monomer. In plain English, it has three or more “arms” that can connect to other pieces, making a strong, net-like structure. The second is a urethane-acrylic monomer, which has two or more connecting arms and brings flexibility and strength to the gel. When these two are mixed and crosslinked (a fancy way of saying they are connected together using heat or light), they make a gel that holds onto the liquid electrolyte very well, but is still soft enough for ions to move through.

The liquid part of the electrolyte includes a mix of lithium salts and organic solvents. Special attention is given to using two different lithium salts—LiDFOB and LiBF4. These salts work together to help build a strong SEI layer inside the battery, which protects it and makes it last longer. The organic solvents include fluoroethylene carbonate (FEC) and diethyl carbonate (DEC), which are known to help battery performance and safety.

One of the smart things about this invention is how the two monomers work together. The acrylic monomer (like dipentaerythritol hexaacrylate, or DPHA) provides a lot of crosslinking points, so the gel holds its shape and doesn’t leak. The urethane-acrylic monomer (such as DRIC, made from special reactions with glycol and trimethylolpropane) brings in flexibility, so the gel doesn’t crack or break when the battery is used over and over. The balance between these two parts can be adjusted, depending on what’s needed for the battery—more strength, more flexibility, or more ionic movement.

Making the gel is simple enough for mass production. The monomers and the liquid electrolyte are mixed together, then heated or exposed to ultraviolet light to start the crosslinking reaction. The result is a gel that can be squeezed into the spaces inside a battery, then cured to hold everything in place. The process is designed to keep the gel’s viscosity (thickness) just right, so it can soak into the battery’s electrodes and separator materials for a solid connection.

Testing showed that batteries made with this gel performed much better than those using older types of gels or just liquid electrolytes. They had higher ionic conductivity (meaning ions could move quickly), better lifespan (lasting more cycles before wearing out), and better high-rate performance (delivering lots of power quickly without failing).

Other smart features include:

• The gel’s design helps trap the liquid, preventing leaks that can cause battery failure or safety issues.
• The use of fluorine-containing salts and solvents helps create a strong, stable SEI, which blocks the growth of dangerous lithium dendrites.
• The monomer mix can be fine-tuned for different types of batteries, whether high-power (for cars) or long-life (for energy storage).
• The process is compatible with standard battery manufacturing, so companies can adopt it without huge changes to their factories.

The patent also describes different ways the gel can be used: as a layer in the separator, in the electrodes, or even as a self-standing film. It can work with lithium metal or lithium-ion batteries, and even with advanced battery types that use solid electrolytes. The gel can be combined with a variety of separator materials (polyethylene, polypropylene, polyimide, and more), making it very flexible for different battery designs.

In summary, the invention offers a gel polymer electrolyte that is safer, lasts longer, and helps batteries deliver more power. It does this by using a clever mix of tough, crosslinking monomers and flexible urethane-acrylic monomers, combined with smart choices of lithium salts and solvents to build a stable, long-lasting battery.

Conclusion

This new gel polymer electrolyte stands out by bringing together the best ideas from past battery research and adding new chemistry to solve old problems. It promises safer batteries that can last longer and deliver more power—key needs for everything from electric cars to smartphones. By making it easy to manufacture and flexible for many battery designs, this invention could help shape the next generation of lithium batteries. As the world demands more from our energy storage, innovations like this one bring us closer to a future where batteries are safer, stronger, and more reliable than ever before.

Click here https://ppubs.uspto.gov/pubwebapp/ and search 20250219137.