GMG Reports 1,000 Six-Minute Charge Cycles for Graphene G Cells
Test data shows the cells maintained performance without reduction, outperforming lithium titanate oxide cells in cycle life and efficiency.
Graphene Manufacturing Group (GMG) has announced that its graphene aluminum-ion G CELLS completed 1,000 six-minute charge and discharge cycles with no performance reduction as of October 7, 2026.
What Happened
The test data was collected by Indiana’s Battery Innovation Center, which built the 1.5 Ah pouch cells. GMG developed and supplied the graphene materials from its Brisbane Battery Development Centre. The cells were charged and discharged at a 7 C rate. According to GMG, this cycle count is double that reported in its previous update, which involved cells cycled at 10 C.
In a comparative test, a lithium titanate oxide (LTO) cell charged and discharged in the same six minutes at 10 C fell to 80% of its original capacity within 82 cycles, a level typically considered end-of-life for a cell. A second G CELL, also tested at 10 C, showed a 10% performance reduction after 393 cycles. The G CELLS achieved a specific energy of 58 Wh/kg at a six-minute (10 C) charge, marking a 48% increase over the 39 Wh/kg reported in GMG’s previous update. Additionally, the G CELLS demonstrated 94% energy efficiency at the six-minute charge and discharge rate, compared with 64% for the LTO cell.
Why It Matters
The results highlight potential advantages in durability and thermal management for graphene aluminum-ion technology compared to existing fast-charging chemistries. Bob Galyen, a GMG Director and former Chief Technology Officer of CATL, stated that "Energy that isn't lost as heat is what makes fast charging practical at the system level." Craig Nicol, Chief Executive Officer and Managing Director of GMG, noted that fast charging remains a significant barrier to broader electric vehicle and energy storage adoption. He emphasized that the new data shows G CELLS lasting approximately ten times longer than a comparable LTO cell under the same rapid cycling conditions.
GMG is developing this technology under a joint development agreement with Rio Tinto. The company’s current focus, as outlined by Nicol, is on improving energy density and 10C cycle life, as well as scaling the technology to larger cell formats.
The Bottom Line
GMG’s latest data presents a case for graphene aluminum-ion cells offering superior cycle life and energy efficiency in ultra-fast charging scenarios compared to LTO benchmarks, with ongoing efforts to enhance energy density and scale production.
