HPQ Silicon has reported that 21700 cylindrical cells made with Novacium’s GEN4 silicon-based anode material achieved an average discharge capacity above 6,600 mAh, with a record cell reaching 6,696 mAh at 319.9 Wh/kg gravimetric and 906.2 Wh/L volumetric energy density, under standard industry test conditions (0.1C discharge, 4.2–2.5 V, 25 °C).
Commercial 21700 graphite cells typically deliver 4,800–5,000 mAh. HPQ notes that capacities above 6,500 mAh in this format are currently limited to a small number of developers globally, citing Molicel, EVE Energy and Amprius as comparables. GEN4 represents a 45% improvement over HPQ’s graphite baseline and a 9% advance over GEN3 in the same format.
The result is the latest step in a staged generational progression. HPQ’s 18650 graphite reference measured 2,778 mAh; subsequent generations in 18650 reached ~3,153 mAh (GEN1), ~3,808 mAh (GEN2) and ~4,030 mAh (GEN3) before the transition to 21700 cells pushed GEN3 to ~6,050 mAh and GEN4 to its current 6,600+ mAh average. Future iterations are targeting the 7,000 mAh range.
The cells were manufactured by an industrial partner, and HPQ describes these as development and validation results rather than commercial production data. HPQ holds exclusive North American rights to commercialize Novacium’s GEN3 and GEN4 materials under the ENDURA+ brand.
“Reaching an average above 6,500 mAh, with a peak of 6,696 mAh, using a material that has not yet been fully optimized, confirms we have an industrially viable, high-performance solution advancing within our commercialization pathway,” said Bernard Tourillon, President and CEO of HPQ Silicon.
Source: HPQ Silicon
