Sodium-ion batteries are getting another chance in the United States as Colorado-based Peak Energy, backed by General Motors, prepares to challenge lithium-iron phosphate batteries in grid storage. The effort follows the collapse of U.S. sodium-ion startups Natron Energy and Bedrock Materials, while China continues expanding its lead in the technology, tells IEEE Spectrum.
Peak Energy plans to build a $71 million factory near Sacramento capable of producing 4 gigawatt-hours of sodium-ion batteries annually. The plant is scheduled to begin operations in 2027. GM is partnering with Peak to co-develop and manufacture the batteries and has been testing its cells at the Wallace Battery Cell Innovation Center.
Peak’s batteries cannot match the energy density or per-cell price of lithium-iron phosphate, or LFP, batteries. However, the company says its GS1.1 storage system could cost operators 20% less over its lifetime. It is designed to operate for 20 years and roughly 20,000 cycles while retaining 80% capacity.
A key advantage is temperature tolerance. Peak’s cells have performed at temperatures up to 55°C, enabling passive cooling without pumps, fans, or fluid-cooling systems. The batteries have also demonstrated 96% round-trip efficiency, about 2–3 percentage points higher than LFP.
Peak uses sodium iron pyrophosphate, or NFPP, cathodes, a chemistry similar to LFP and also adopted by CATL. This compatibility could allow sodium-ion cells to be manufactured in existing battery plants.
The company is also pursuing commercial deployments with RWE Americas and Jupiter Power. Its agreement with Jupiter could supply up to 4.75 gigawatt-hours through 2030.
Sodium is far more abundant than lithium, but challenges remain. China still dominates sodium processing and cell production. Peak and GM nevertheless expect sodium-ion cells to reach price parity with LFP around 2028, potentially establishing sodium-ion technology as a practical complement to lithium for stationary energy storage.