Amprius Technologies (NYSE: AMPX) announced a second-generation SiCore 500 battery cell rated at 500 Wh/kg, targeting long-endurance unmanned aviation applications including High-Altitude Platform Stations and fixed-wing drones.

According to the company, the cell delivers 500 Wh/kg at a 1C continuous discharge rate and is designed to be produced on conventional lithium-ion manufacturing equipment. Amprius said previous cells it developed that reached or exceeded 500 Wh/kg relied on specialized processes and were never produced at commercial volume.

Commercial availability is expected in Q4 2026. Initial production is planned at the company's Fremont, California facility, with volume production intended to scale through existing global contract manufacturing partners. The cell will be offered in customer-specific formats and in the standard small uncrewed aircraft systems pouch format defined by SAE JA1016.

Amprius has supplied cells to AALTO HAPS, an Airbus subsidiary, since 2018 across multiple generations of its Zephyr solar-electric platform. A 2025 Zephyr flight has reported setting a 67-day endurance record.

"Energy density is fundamental to Zephyr's endurance," said Pierre-Antoine Aubourg, COO at AALTO HAPS. "Continued gains in specific energy can meaningfully extend flight duration and expand mission capability."

"By achieving that performance level on conventional manufacturing equipment, our aviation customers can qualify this cell knowing that we have designed a cost-effective, scalable path to volume behind it," said Dr. Ionel Stefan, CTO of Amprius Technologies.