A Tsinghua University-led research team in China has developed a tiny, all-ceramic solid-state lithium-ion battery (ACMLB) designed to safely power miniature electronics in extreme environments.

It handles intense heat without breaking a sweat. According to the study, these tiny powerhouses operate flawlessly at temperatures up to 150°C (302°F). And can even survive sudden, blistering thermal shocks of 300°C (572°F) for 20 seconds.

“The ACMLBs show great electrochemical performance over a wide temperature range (0°C–150°C),”  the researchers noted in the study paper. It further added that these batteries “offer non-flammability and high safety, providing a reliable and high-performance power solution for wearable miniaturized electronic devices.”

Heat-resistant battery

Standard lithium-ion batteries are widely used for their high energy density, but the volatile liquid electrolytes pose severe flammability and explosion risks when exposed to high heat or physical damage. 

This safety hazard limits their use in harsh environments like aerospace equipment, military applications, and industrial Internet of Things (IoT) sensors. 

Solid-state lithium batteries offer a non-flammable alternative by replacing liquids with solid mediums, but developing all-ceramic versions for miniature devices has been difficult. This is due to a thickness-strength trade-off, in which making the ceramic layers thin enough for microelectronics severely compromises the structural strength.

To fix this, the Tsinghua team used a brilliant manufacturing trick: stacking multiple ceramic layers.

Multilayer stacking solves the classic engineering problem of oxide electrolytes: making them thin enough for high energy density while keeping them strong enough to prevent mechanical failure. This stacking architecture also scales up the capacity of individual cells.

During the co-sintering process (heating materials together), a custom chemical layer forms naturally at the boundaries. This microscopic layer filled every internal gap, gluing the battery together while allowing lithium ions to race through it. 

Use in miniature devices

This process creates a highly customizable, stackable battery that scales easily to fit different devices while remaining perfectly stable across a range of temperatures. 

The newly designed ceramic battery operates at 150°C — a temperature that would cause a normal smartphone battery to swell, rupture, or burst into a chemical fire within minutes. 

During room-temperature testing, the battery proved highly stable, keeping over 76 percent of its original capacity after 100 charge cycles while maintaining a steady power output.

The research paper explained technically: “A 10-parallel ACMLB subjected to long-term cycling at room temperature at 50 μA cm⁻² current density exhibited an initial capacity of 105 μAh, retaining 80 μAh after 100 cycles, which corresponds to a capacity retention rate of 76.2%.” 

Interestingly, it requires zero external pressure to hold its shape. Even better, it can be manufactured in normal air rather than an expensive, airtight vacuum lab, lowering potential production costs. 

“It is completely non-combustible and maintains structural integrity under sustained external combustion and has excellent thermal stability in air, significantly outperforming batteries with liquid, polymer or composite electrolytes in terms of safety,” the study noted. 

In the future, the researchers believe this innovation has the potential to accelerate the commercialization of all-solid-state electronics for miniature and wearable devices. Its high energy density and non-flammable safety profile make it ideal for next-generation technologies, including smart sensors, aerospace gadgets, and military applications. 

The findings were published in the journal Matter. 

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