WeLion Named a Company to Watch by MIT for Its Semi-Solid-State Batteries

China's WeLion New Energy has been named one of MIT Technology Review's "10 Climate Tech Companies to Watch in 2026." WeLion focuses on semi-solid-state batteries, which use an electrolyte that is a mix of liquid and solid. All-solid-state batteries are extremely difficult to manufacture.

Unlike conventional lithium-ion batteries, semi-solid-state batteries use less flammable liquid in the electrolyte (the material that allows ions to move within the battery), making them less prone to fire and capable of storing more energy per charge—driving growing demand in electric vehicles and beyond. In 2025 tests, WeLion engineers developed a semi-solid-state battery with an energy density of 824Wh/kg. In 2023, the company partnered with Shanghai-based EV maker Nio to launch a 360Wh/kg battery pack that delivered a driving range of more than 1,000 kilometers on a single charge.

However, early commercialization has come with burdens. Due to high production costs, only about 200 of the Nio battery packs were made. According to WeLion, the packs are still in use by Nio today. This shows that while semi-solid-state batteries have proven their performance, the challenge remains to reduce mass-production costs.

WeLion's applications are expanding beyond electric vehicles. Through a subsidiary, the company has built batteries for cargo ships and ferries, and it aims to apply its technology in diverse fields including drones.