HPQ Silicon Inc., a materials innovation company focusing on next-generation battery processes, reported that 21700 cylindrical cells using Novacium SAS’s GEN4 silicon-based anode have surpassed 7,000 mAh in capacity under extended operating conditions. Internal tests conducted at 0.1 C between 4.2 V and 0.55 V at 25 °C yielded a record discharge capacity of 7,030 mAh—one of the highest values publicly recorded for an industrial 21700 format.
The deep-discharge protocol employed a lower cutoff voltage of 0.55 V, well below the conventional 2.5 V threshold. While standard 21700 graphite cells typically deliver 4,800 to 5,000 mAh, and the previous GEN4 benchmark was 6,696 mAh under industry-standard conditions, the new result demonstrates the material’s ability to access an expanded voltage window without rapid degradation.
Over 70 full cycles under these rigorous conditions, capacity loss remained under 2%, indicating robust stability compared to conventional cells, which often suffer irreversible damage when discharged deeply. This resilience suggests silicon-based anodes may enable operating modes that extend beyond current voltage limits in lithium-ion design.
HPQ Silicon holds exclusive rights in North America to commercialize Novacium’s GEN3 and GEN4 silicon anode materials under its ENDURA+ brand. The progression from a 2,778 mAh 18650 graphite reference through successive GEN innovations to the current breakthrough highlights steady improvements in energy density. Development of GEN5 targets achieving 7,000 mAh under standard protocols by 2027.
These findings point toward potential high-energy-density applications—such as electric vehicles and portable power—where capacity per unit volume is a primary constraint. However, additional validation, optimization, and system-level integration are required to confirm commercial viability. Detailed technical information and context are available on HPQ’s technical blog.
Source: HPQ Silicon press release
