Chinese solid-state battery developer WeLion is advancing steadily toward its long-term goal of achieving an energy density of 1,000 Wh/kg. The company has already reached 824 Wh/kg in laboratory tests, though the battery is not yet ready for commercial release.

Like other firms in the field—such as Factorial, a Mercedes partner, and Volkswagen-backed QuantumScape—WeLion has invested years in solid-state battery research. This technology replaces liquid electrolytes with solid ones between the cathode and anode, promising major gains in range, charging speed, and safety compared to conventional batteries.

WeLion, which already supplies semi-solid-state batteries to Nio, recently hit a significant research milestone. CEO Yu Huigen announced that the company has demonstrated a record energy density of 824 watt-hours per kilogram (Wh/kg) in lab conditions. “We expect to break the 1,000 Wh/kg barrier in the long term,” Yu stated.

By comparison, today’s typical LFP batteries offer between 150 and 180 Wh/kg. Many other solid-state battery developers are targeting 350 to 500 Wh/kg. That puts WeLion alone in publicly discussing energy densities above 800 Wh/kg—let alone beyond 1,000 Wh/kg. The company has not, however, detailed how it intends to sustain such a large lead over rivals.

According to Car News China, Yu acknowledged that cost remains the main barrier to mass commercialization, especially due to expensive raw materials in sulfide-based electrolyte systems. “Initially, these batteries will be deployed in price-insensitive applications where safety is paramount,” he explained, suggesting potential uses in areas such as humanoid robots.

WeLion already operates production facilities in Beijing, Jiangsu, Zhejiang, and Shandong, with current annual capacity of 28.2 GWh and plans to surpass 100 GWh. The company aims to start mass-producing solid-state batteries by 2027 and is considering an initial public offering. If it proceeds, WeLion could become China’s first publicly listed pure solid-state battery firm.