Forward-looking: It's no secret that lithium-ion batteries aren't perfect, but their supposed successor---solid-state batteries---are yet to make it into high-volume production, but that's starting to change.

According to Chinese media outlets (via Electrek), a startup called Qing Tao Energy Development Co, which was spun off from Tsinghua University, has deployed the first solid-state battery production line in the country.

Solid-state batteries use both solid electrodes and solid electrolytes, instead of the liquid or gel-form electrolyte found in lithium-ions. This makes them not only safer than today's batteries, but also able to achieve a higher energy density. According to the startup, it has achieved an energy density of over 400 Wh/kg, beating new Lithium-ion's capacity of 250 to 300 Wh/kg.

The company has invested 1 billion yuan ($144 million) into the project, and the line has a capacity of 100 MWh per year. That would only be enough for 2000 long-range electric vehicles, but the plan is to increase this up to 700 MWh by 2020.

Nan Cewen, who founded the company alongside several Ph.D. graduates from Tsinghua University in 2014, said Volkswagen, Toyota, and Dyson were all working on solid-state battery tech, as are other companies such as BMW and Fisker.

"Getting rid of liquid electrolytes can ensure the battery is not flammable or combustible and can even be produced in flexible packs," Nan said.

It will be a long time before solid-state batteries replace lithium-ions, but this production line could be another early step toward that day.