Solid-state battery prototype boosts energy density by nearly 25 percent

Solid-state batteries have the potential to make EVs far more affordable and practical, but their commercial development has a record of false promises that would make Tesla's full self-driving blush. That means reporting on them is tricky, but we're seeing some promising news from Imec, a well-established R&D giant based in Belgium.

As part of its SOLiDIFY project, the EU-supported firm and its 13 partners have manufactured a prototype solid-state battery with a 1070 Wh/L energy density, nearly 25 percent higher than the best lithium-ion cells (800 Wh/L). Better still, it uses a manufacturing process that works at room temperature, is adaptable to current lithium-ion battery product lines and is projected to cost less than 150 euros (about $167) per kWh, compared to about $140/kWh for current batteries. "This process holds promise for affordable industrial transfer," Imec wrote in a press release.

The breakthrough was something called "liquid-to-solid" solidification. That means the prototype's solid electrolyte uses a "doped polymerized ionic liquid" in a thin 50 micrometer layer. The electrolyte is flanked by a high-capacity composite cathode on one side and a thin lithium metal anode on the other, resulting in a compact battery cell stack.

The consortium was able to boost the cell's charge rate to three hours and lifetime to 100 cycles, overcoming mechanical strength and cathode impregnation challenges. Use of cobalt was also reduced thanks to the application of nanometer-thin protective coatings.

Clearly the charging times and number of cycles need to improve (modern li-ion car batteries can be charged 2000 times and some in well under an hour). In addition, the technology requires further upscaling to be practical on an industrial level. It's worth the effort, though, as solid-state batteries could eventually deliver improved energy density, lower charging times and better safety, all at a lower price.