Canada-based HPQ Silicon has reported that its latest silicon-based lithium-ion cells have exceeded 7000 mAh capacity in testing, marking what it describes as a milestone for industrial-format cylindrical batteries.
The company said 21700 cells using Novacium’s GEN4 silicon anode material achieved a discharge capacity of 7030 mAh under extended test conditions.
The result was obtained using a modified deep-discharge protocol, lowering the cut-off voltage to 0.55V compared with the industry-standard 2.5V. Commercial graphite-based 21700 cells typically deliver between 4,800 and 5,000mAh.
HPQ said the cells maintained stability during testing. The GEN4 material completed 70 cycles under the extended protocol with less than 2% capacity degradation—conditions that would normally cause severe degradation in conventional lithium-ion chemistries.
Breaking the 7000 mAh barrier
Bernard Tourillon, president and CEO of HPQ Silicon, said: “Breaking the 7000 mAh barrier in a 21700 cell is a milestone that, to the Company’s knowledge, has not been widely reported in publicly available data for an industrial-format cell under comparable conditions. What is equally important is that we achieved this while maintaining initial cycle stability over the test period, thereby indicating that our material can operate under extended conditions that, according to published literature, typically result in severe degradation or loss of functionality in conventional graphite-based lithium-ion cells.”
Dr Jed Kraiem, COO of Novacium, added: “These results confirm something we have believed since GEN3: Novacium’s silicon-based anode technology may enable performance improvements beyond conventional operating constraints. The ability to cycle reliably at 0.55V lower cutoff with less than 2% degradation over 70 cycles suggests the possibility of alternative operating modes, subject to further validation and engineering development.”
The company said the breakthrough builds on a progression of improvements from earlier generations, with GEN4 previously reaching 6696 mAh under standard testing conditions.
HPQ noted that while the results point to potential for higher energy-density applications, further validation and system-level development will be required before commercial deployment. It is targeting a GEN5 iteration capable of achieving around 7,000 mAh under standard protocols by 2027.
Photo: two GEN 4 cells that have reportedly broken the 7000 mAh barrier
Credit: © HPQ Silicon
