Amprius Targets Longer Drone Flights With New 500 Wh/kg Battery Cell

Second-generation SiCore technology pairs higher energy density with a path to volume productio

Amprius Technologies has introduced a silicon-anode battery cell designed for long-endurance uncrewed aircraft. The company says its second-generation SiCore cell delivers 500 watt-hours per kilogram (Wh/kg) at a 1C continuous discharge rate.

The company expects to make the cell commercially available in the fourth quarter of 2026. It plans to offer customer-specific formats and a standard pouch format for small uncrewed aircraft systems.

The energy-density figure measures how much energy a battery stores for its weight. In aviation, higher specific energy can support longer flights, more range, or added payload without raising battery weight.

A Focus on Scalable Production

Amprius has previously developed cells that reached or exceeded 500 Wh/kg. However, the company says those cells required specialized processes and never reached commercial production volumes.

The new SiCore platform aims to deliver the same energy level using conventional lithium-ion equipment, processes, and cell formats. According to Amprius, this approach could let customers move from qualification to volume production without specialized tooling.

“Reaching 500 Wh/kg is a significant technical milestone, but how we reached it matters as much as the number,” said Dr. Ionel Stefan, CTO of Amprius Technologies. “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.”

Amprius uses an asset-light model that relies on contract manufacturers for larger-scale production. The company plans to begin initial production at its Fremont, California, facility. It expects to expand volume through its existing global manufacturing partners.

Customers will still need to qualify the cells for their aircraft and operating needs. Commercial-scale results may also differ from performance achieved during testing or limited production.

Designed for Long-Endurance Flight

Amprius optimized the cell for sustained, low-rate discharge. Target applications include fixed-wing drones, High-Altitude Platform Stations (HAPS), and other long-endurance aircraft.

Battery weight plays a central role in HAPS operations. Solar-powered fixed-wing aircraft must store enough daytime energy to continue flying overnight. Lighter-than-air platforms also need stored power for propulsion and station keeping.

Amprius has supplied battery cells to AALTO HAPS since 2018. AALTO, an Airbus subsidiary, develops the solar-electric Zephyr aircraft for connectivity and Earth observation missions. The company reports that a 2025 Zephyr flight set an endurance record of more than 67 days.

“Energy density is fundamental to Zephyr’s endurance,” said Pierre-Antoine Aubourg, COO at AALTO HAPS. “Our longstanding relationship with Amprius has focused on advancing the energy storage required for persistent stratospheric flight. Continued gains in specific energy can meaningfully extend flight duration and expand mission capability.”

Amprius plans to offer the new cell in the small UAS pouch format defined by SAE JA1016.

The announcement reflects the aviation battery sector’s push to combine higher energy density with practical manufacturing. For drone makers, the cell’s value will depend on production-scale performance, safety, cycle life, cost, and successful integration. Amprius expects customers to begin evaluating those factors when the SiCore500 becomes available later this year.

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