Graphene Manufacturing Group (GMG) reported that its G CELLS demonstrated no measurable capacity loss after 489 fast-charge cycles. Testing was conducted by the Battery Innovation Center of Indiana (BIC) using 1 Ah pouch cells, with each charge and discharge cycle completed within six minutes at a 10 C rate.
The test cells were created by BIC using graphene materials supplied by GMG from its Brisbane Battery Development Centre. This project is part of a joint development agreement between GMG and Rio Tinto. G CELLS are graphene aluminum-ion batteries that contain no lithium or rare earth materials and are intended to be interchangeable with lithium-ion applications.
In comparative tests, a lithium titanate oxide (LTO) cell dropped to 86% of its original capacity after 64 cycles. GMG noted that its cells offer more than seven times the cycle life under identical conditions. Additionally, G CELLS showed an internal resistance of about 5 mΩ, compared to 30 mΩ for the LTO cell, resulting in lower resistive heating during operation.
During testing, G CELLS operated at 4° C above ambient temperature, while LTO cells reached 19° C above ambient. While current specific energy levels are lower than previously reported, GMG plans to optimize the cells to reach approximately 50 Wh/kg at the same charge rate. The voltage remained nearly flat throughout 80% of the discharge cycle.
