Traditional lithium-ion batteries, which power a wide range of electronic devices from cars to smartwatches, pose a significant fire risk. When damaged, overcharged, or defective, they can undergo thermal runaway — a dangerous event in which internal components break down and release extreme heat. In a typical battery, this can cause temperatures to spike by over 500 °C, leading to fires and explosions.

Now, a team of researchers in China, primarily from the Chinese University of Hong Kong, has developed a new battery design that mitigates this risk. In a study — published in the journal Nature — the team detailed the new design and test results. When penetrated with a nail, the lithium-ion battery made with this design saw a temperature rise of about 3.5 °C and remained stable. As for the battery with conventional electrolytes, a temperature spike of 555.2 °C, explosion, and fire were recorded.

Video source: Sun, Y., Zuo, C., Wang, H. et al (2025).

The team was only able to make this breakthrough after identifying the culprit — ion association. In conventional batteries, the way lithium ions and negative ions group together in the electrolyte is good for forming a protective layer called the solid electrolyte interphase (SEI), which is vital for a long cycle life. However, the researchers discovered this same ion association also lowers the temperature at which thermal runaway begins by approximately 94 °C, making the battery far less safe.

To solve this trade-off, the team developed what they call a “solvent-relay strategy.” They engineered a new electrolyte that behaves differently at different temperatures. At room-temperature conditions, it promotes the ion association needed for good SEI formation. But at elevated temperatures — like those from damage — a specific solvent called lithium bis(fluorosulfonyl)imide steps in, bonding with the lithium and promoting ion dissociation. This action inhibits the dangerous anion bonds that would otherwise lead to heat release.

The design proved to be both safe and durable. The cells designed with their new strategy also demonstrated an exceptional cycle life, retaining approximately 81.9% of their capacity after 1,000 cycles.

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Chibuike Okpara – Tech Writer – 278 articles published on Notebookcheck since 2024

I have always been fascinated by technology and digital devices my entire life and even got addicted to it. I have always marveled at the intricacy of even the simplest digital devices and systems around us. I have been writing and publishing articles online for about 6 years now, just about a year ago, I found myself lost in the marvel of smartphones and laptops we have in our hands every day. I developed a passion for learning about new devices and technologies that come with them and at some point, I asked myself, “Why not get into writing tech articles?” It is useless to say I followed up the idea — it is evident. I am an open-minded individual who derives an infinite amount of joy from researching and discovering new information, I believe there is so much to learn and such a short life to live, so I put my time to good use — learning new things. I am a ‘bookworm’ of the internet and digital devices. When I am not writing, you will find me on my devices still, I do explore and admire the beauty of nature and creatures. I am a fast learner and quickly adapt to changes, always looking forward to new adventures.