Solid state lithium metal battery for smartphones

Solid state lithium metal battery for smartphones

Technology News |
By Nick Flaherty

Xiaomi in China has shown a solid-state battery technology that provides higher mechanical strength and stability as well as higher capacity in a smartphone.

In laboratory tests, the solid-state battery technology achieved an energy density of over 1000Wh/L, a 20% improvement in low-temperature discharge performance and a significant increase in the pass rate of pinprick experiments.

The energy density of 1000Wh/l tops the 800Wh/l of silicon-based lithium ion packs with a liquid electrolyte. Ilika in the UK and Solithor in Belgium and iten in France are all working on solid state battery systems, and Sakuu in the US has demonstrated 3D printed lithium metal solid state cells. 

The solid state battery uses a lithium metal anode with an inorganic diaphragm to prevent the growth of lithium dendrites that can penetrate the layers of the cell and cause short circuits and fires.

On a modified Xiaomi 13 (above), the battery achieved a capacity of 6,000mAh with higher reliability.

By coating the positive electrode with a solid electrolyte ceramic, the solid electrolyte layer forms a downward curve to enclose the positive current collector fluid and separate it from the negative electrode. This blocks any contact between the positive and negative electrodes during the piercing, markedly increasing the pass rate of the pinprick test, and providing a higher level of safety in use.

Another major benefit of solid-state batteries is the improved performance at low temperatures. The liquid electrolyte in traditional batteries has a high viscosity at low temperatures, hindering the ability to transport lithium ions and resulting in a drastic 60% drop in lithium conductivity, which greatly impacts the battery performance in winter.

The labs tests shows the solid-state battery has a 20% improvement in performance compared to regular batteries at -20°C, providing reliable operation in cold climates and conditions.

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