Graphene Manufacturing Group's fast-charging battery cells show no performance loss Proactive uses images sourced from Shutterstock

Graphene Manufacturing Group Ltd (TSX-V:GMG, OTCQX:GMGMF) said its fast-charging GCELLS have shown no reduction in performance after 489 charge cycles, each completed within six minutes, in the latest data from its battery development program with Rio Tinto.

The cycling data, collected by the Battery Innovation Center of Indiana on 1 Ah cells built with materials developed and supplied by GMG's Brisbane Battery Development Centre, compared the GCELLS against a well-known Lithium Titanate Oxide battery tested under the same charging profile. The LTO cell degraded to 86% of its original capacity, near the industry's typical 80% end-of-life threshold, within just 64 cycles.

GMG said its cells have effectively lasted more than seven times longer than the LTO comparison under identical testing conditions.

Craig Nicol, CEO of GMG, said the data is an important proof point for the program, showing GCELLS can be repeatedly fast-charged with no measurable degradation, well beyond where the LTO comparison reached end of life. “Energy density is an area we are continuing to optimise, and we are confident, based on the pathway BIC and our own team have identified, that we can lift this back towards 50 Wh/kg at a 10C charge rate as this program matures.”

Bob Galyen, GMG director and former chief technology officer of CATL, called the cycling stability "genuinely exceptional," noting the low internal resistance of around 5 mOhms and a 4 degree temperature rise above ambient show the material science is translating into real cell-level performance.

Jack Perkowski, chairman of GMG, said that BIC's independently measured data gives the board confidence in the program's direction as management works through the optimisation steps ahead.

The work is being carried out under a Joint Development Agreement between GMG and Rio Tinto, one of the world's largest metals and mining groups, with support from the Battery Innovation Center of Indiana in the United States.

Shares were up 2.4% on Wednesday.