Factorial Energy announced a strategic partnership with Mitsui Kinzoku, one of the few manufacturers of high‑performance sulfide‑based solid electrolytes, to accelerate the scale‑up of its next‑generation all‑solid‑state battery (ASSB) platform. The deal, disclosed on 17 September 2026, will see Mitsui Kinzoku supply its proprietary sulfide electrolyte material to Factorial’s pilot production line, while jointly investing in equipment to increase annual output from the current low‑tonnage pilot scale to a multi‑kiloton capacity within the next 24 months Electrek.

Factorial’s ASSB architecture relies on a lithium‑metal anode paired with a thin, high‑ionic‑conductivity sulfide electrolyte, promising energy densities above 500 Wh kg⁻¹ and a safety profile that eliminates the flammable liquid electrolyte of conventional lithium‑ion cells. The partnership is significant because sulfide electrolytes, while offering the highest ionic conductivities (>10 mS cm⁻¹), have historically been hampered by moisture sensitivity and costly processing. Mitsui Kinzoku’s recent advances in moisture‑stable, low‑impedance sulfide formulations could reduce the electrolyte cost to under $30 kWh⁻¹, a key threshold for commercial viability.

The collaboration also includes a joint R&D program focused on interface engineering to suppress dendrite formation at the lithium‑metal/solid‑electrolyte interface, a persistent challenge for ASSBs. Early test cells from the partnership have demonstrated 80 % capacity retention after 1,000 cycles at 1 C charge/discharge rates, a performance level that rivals early‑stage lithium‑ion packs.

If successful, the scaled‑up supply chain could enable Factorial to launch its first commercial solid‑state module for high‑energy‑density electric‑vehicle applications by 2028, positioning the company alongside QuantumScape and Solid Power in the race to replace liquid‑electrolyte packs. The partnership underscores a broader industry shift toward securing dedicated solid‑electrolyte sources, a critical step in moving ASSBs from laboratory prototypes to mass‑produced products.

ProLogium, a Taiwanese developer of all‑inorganic solid‑state batteries, announced a memorandum of understanding (MoU) with Dutch aerospace startup Elysian Aircraft on 22 September 2026. The two firms will explore the integration of ProLogium’s high‑energy‑density solid‑state cells into Elysian’s next‑generation electric aircraft concepts, aiming to achieve fully zero‑emission regional flight by the early 2030s ProLogium.

ProLogium’s flagship solid‑state cell features a garnet‑type LLZO (lithium‑lanthanum‑zirconium‑oxide) ceramic electrolyte and a lithium‑metal anode, delivering a specific energy of roughly 550 Wh kg⁻¹ at a safe operating temperature of 30‑60 °C. Compared with conventional lithium‑ion packs, the technology promises a 30‑40 % weight reduction for the same range, a critical advantage for aircraft where every kilogram impacts payload and efficiency.

The MoU outlines three phases: (1) feasibility studies and safety certification simulations; (2) prototype cell integration into a scaled‑down electric propulsion testbed; and (3) a full‑scale flight‑demo platform slated for 2029. Both parties will share testing facilities, with ProLogium providing battery modules and Elysian contributing airframe design and flight‑control integration expertise.

A key technical hurdle is the high power demand of take‑off and climb phases, which requires solid‑state cells capable of delivering >2 C discharge without compromising cycle life. ProLogium claims its latest cell architecture can sustain 3 C bursts while maintaining >90 % capacity after 500 cycles, a performance level that, if validated, could make solid‑state batteries a realistic alternative to hydrogen or turbine‑based hybrid systems for short‑haul routes.

The collaboration signals growing confidence that solid‑state technology can meet the stringent safety and reliability standards of aviation. Successful demonstration would not only accelerate the decarbonisation of regional air travel but also open a high‑value market for solid‑state manufacturers, potentially driving further investment in electrolyte materials and manufacturing processes. The partnership positions ProLogium as a front‑runner in the emerging aerospace battery segment, complementing its existing automotive and stationary‑storage programs.