Pull to refresh
Logo
Daily Brief
Following Why Ranks Sign Up
Chinese researchers build first sodium-ion battery that survives extreme heat without catching fire

Chinese researchers build first sodium-ion battery that survives extreme heat without catching fire

New Capabilities

A self-solidifying electrolyte published in Nature Energy eliminates thermal runaway in large-format sodium-ion cells, clearing a major safety barrier for cheaper, lithium-free electric vehicles

April 9th, 2026: CAS publishes fireproof sodium-ion battery in Nature Energy

Overview

Every rechargeable battery in every electric car on the road carries the same vulnerability: if something goes wrong inside a cell — a puncture, a manufacturing defect, a short circuit — temperatures can spike and trigger a self-feeding chain reaction called thermal runaway, producing toxic smoke, fire, and sometimes explosions. A team at the Chinese Academy of Sciences has now published results in Nature Energy showing a sodium-ion battery with a built-in chemical failsafe: an electrolyte that automatically solidifies into a physical barrier when the cell heats past 150 degrees Celsius, cutting off the chain reaction before it starts. The battery survived both nail-puncture and 300-degree-Celsius oven tests with zero smoke, fire, or explosion — a first for a large-format sodium-ion cell.

The breakthrough matters for two reasons. First, it addresses the single biggest consumer fear about electric vehicles — that their batteries can catch fire — using a mechanism that requires no external sensors, cooling systems, or electronics. Second, it does so in a sodium-ion battery, a cheaper chemistry that replaces lithium with the sixth most abundant element in Earth's crust, sidestepping the volatile lithium supply chain entirely. With an energy density of 211 watt-hours per kilogram and an operating range from minus 40 to 60 degrees Celsius, the cell is competitive with current lithium iron phosphate batteries already powering millions of vehicles. The gap between laboratory proof and factory production remains, but the raw materials are conventional industrial chemicals, which the researchers say makes scale-up feasible.

Why it matters

A fireproof, lithium-free battery that uses Earth's most abundant materials could make electric vehicles both safer and cheaper at scale.

Play on this story Voices Debate Predict

Key Indicators

211 Wh/kg
Energy density achieved
Competitive with lithium iron phosphate batteries already used in production electric vehicles
150°C
Self-protection trigger temperature
The electrolyte solidifies into a physical barrier at this threshold, shutting down ion transport before thermal runaway begins
300°C
Hot-box test survived
The cell produced no smoke, fire, or explosion at 572 degrees Fahrenheit — well beyond normal failure temperatures
0
Thermal runaway events in testing
First ampere-hour-level sodium-ion cell to achieve zero thermal runaway in both nail-penetration and extreme-heat tests
4.3V+
Operating voltage
High voltage stability expands the range of cathode materials and applications the electrolyte can support

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

Sign up to generate historical perspectives on this story.

Log in Sign Up

Play

Exploring all sides of a story is often best achieved with Play.

Log in to play. Track your picks, climb the leaderboards. Log in Sign Up
Predict 4 ways this could play out. Contrarian picks score more — points lock when the scenario resolves. Log in to play
Timeline Five events from this story — drag them oldest to newest. Log in to play
Connections Sixteen names from the news. Find the four hidden groups of four. Log in to play

People Involved

Hu Yongsheng
Hu Yongsheng
Lead researcher on the Nature Energy study

Organizations Involved

Chinese Academy of Sciences (CAS)
Chinese Academy of Sciences (CAS)
National Research Institution
Publisher of the Nature Energy study via its Institute of Physics

China's premier national science body, operating over 100 research institutes and serving as a pipeline from fundamental research to commercial technology spin-offs.
Contemporary Amperex Technology Co. Limited (CATL)
Contemporary Amperex Technology Co. Limited (CATL)
Battery Manufacturer
World's largest battery maker; already mass-producing sodium-ion cells

The world's largest electric vehicle battery manufacturer, CATL launched its Naxtra sodium-ion battery brand in 2025, making it the first major producer to bring the technology to mass-market vehicles.
HiNa Battery Technology
HiNa Battery Technology
Battery Manufacturer (CAS Spin-off)
First company to deploy sodium-ion batteries in passenger vehicles

A direct spin-off of the Chinese Academy of Sciences' sodium-ion research, HiNa was the first company to put sodium-ion batteries into an electric car and now operates commercial-scale manufacturing.
BYD Company Limited
BYD Company Limited
Automaker and Battery Manufacturer
Building 30 GWh sodium-ion factory; third-generation sodium-ion technology in development

The world's largest electric vehicle maker by sales, BYD broke ground on a 30-gigawatt-hour sodium-ion battery factory in January 2024 and has achieved 10,000-cycle durability in its third-generation sodium-ion platform.

Timeline

July 2021 April 2026

9 events Latest: April 9th, 2026 · 1 month ago
Tap a bar to jump to that date

  1. CAS publishes fireproof sodium-ion battery in Nature Energy

    Latest Research

    Hu Yongsheng's team at the Chinese Academy of Sciences published results of a polymerizable non-flammable electrolyte that solidifies at 150 degrees Celsius, creating a physical barrier that prevents thermal runaway. The ampere-hour-level cell achieved 211 watt-hours per kilogram and passed nail-penetration and 300-degree hot-box tests with zero fire, smoke, or explosion.

  2. MIT Technology Review names sodium-ion a 2026 breakthrough technology

    Recognition

    Sodium-ion batteries were selected as one of MIT Technology Review's 10 Breakthrough Technologies for 2026, recognizing the chemistry's rapid progress from lab curiosity to commercial reality.

  3. Li Auto recalls 11,000 vehicles over battery fire risk

    Safety Incident

    Chinese automaker Li Auto recalled its flagship Mega electric vehicle after a battery fire in Shanghai, citing a coolant defect that could trigger thermal runaway.

  4. CATL launches mass-produced sodium-ion battery brand

    Industry

    CATL introduced its Naxtra sodium-ion battery line, becoming the first major manufacturer to begin mass production of the chemistry for vehicles and energy storage.

  5. Lithium battery factory fire kills 23 in South Korea

    Safety Incident

    An explosion at the Aricell lithium battery factory in Hwaseong killed 23 workers, mostly migrant laborers. The fire reignited global attention on battery safety and the risks of thermal runaway in manufacturing and storage.

  6. BYD breaks ground on 30 GWh sodium-ion factory

    Industry

    BYD began construction on a massive sodium-ion production facility, signaling the chemistry's transition from niche to mainstream.

  7. First sodium-ion battery installed in a passenger car

    Milestone

    HiNa placed a 140 watt-hour-per-kilogram sodium-ion pack in a Sehol E10X, marking the first time the chemistry powered a passenger vehicle.

  8. HiNa opens first gigawatt-hour sodium-ion factory

    Industry

    The CAS spin-off began pilot production of sodium-ion cells in Liyang, Jiangsu province, becoming the first dedicated sodium-ion manufacturing facility at scale.

  9. CATL unveils first sodium-ion battery

    Industry

    The world's largest battery maker revealed a first-generation sodium-ion cell with 160 watt-hours per kilogram and the ability to charge to 80 percent in 15 minutes, signaling that the chemistry was ready for commercial development.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

March 2020

BYD Blade Battery nail-penetration test (2020)

BYD publicly demonstrated its Blade Battery, a lithium iron phosphate cell in a thin, elongated form factor, passing a nail-penetration test — the most demanding battery safety standard — without producing smoke or fire. The cell surface reached only 30-60 degrees Celsius. Conventional nickel-manganese-cobalt cells subjected to the same test burst into flames.

Then

The demonstration made global headlines and gave BYD a powerful marketing differentiator. The Blade Battery became standard across BYD's vehicle lineup.

Now

It proved that cell-chemistry-level safety — rather than pack-level engineering workarounds — was commercially viable and consumer-relevant, setting the benchmark that the CAS sodium-ion research now builds upon.

Why this matters now

The CAS fireproof sodium-ion battery passes the same nail-penetration test, but using an even cheaper, more abundant chemistry. If BYD's Blade Battery showed that inherent safety sells cars, the CAS breakthrough shows it can be done without lithium at all.

June 2024

Hwaseong Aricell lithium battery factory fire (2024)

At the Aricell factory in Hwaseong, South Korea, a single lithium battery cell caught fire and triggered a cascade that engulfed 35,000 batteries on the building's second floor. Twenty-three workers — mostly undocumented Chinese migrant women — died from toxic smoke inhalation within minutes. The fire was so intense and toxic that firefighters could not enter the building.

Then

South Korea launched safety reviews of battery manufacturing facilities. The incident drew global attention to thermal runaway risks not just in vehicles but in production and storage.

Now

The disaster intensified regulatory pressure across Asia and Europe for inherently safer battery chemistries and stricter factory safety standards.

Why this matters now

The Hwaseong fire demonstrated in human terms what thermal runaway means at scale. A battery chemistry that physically cannot sustain chain-reaction fires — as the CAS electrolyte aims to deliver — would address the exact failure mode that killed 23 workers.

July 2021

CATL first-generation sodium-ion battery announcement (2021)

CATL, the world's largest battery manufacturer, unveiled a first-generation sodium-ion cell achieving 160 watt-hours per kilogram with fast-charging capability — significantly below lithium-ion energy density but using materials costing a fraction as much. The company announced plans for commercial production by 2023 and an innovative hybrid pack mixing sodium-ion and lithium-ion cells.

Then

The announcement legitimized sodium-ion as a serious commercial chemistry, triggering a wave of investment and research across the industry.

Now

By 2025, CATL was mass-producing sodium-ion batteries under its Naxtra brand, BYD was building a 30-gigawatt-hour factory, and MIT Technology Review named sodium-ion a top-10 breakthrough technology for 2026.

Why this matters now

CATL's 2021 announcement solved sodium-ion's credibility problem. The CAS fireproof electrolyte now solves its remaining safety gap, potentially making sodium-ion competitive with lithium-ion on every metric that matters to consumers: cost, safety, and adequate range.

Sources

(9)
+3
Nature Energy People's Daily Online Xinhua TechRadar Chinese Academy of Sciences Interesting Engineering CarNewsChina MIT Technology Review MIT Technology Review