Revealing the synergetic electrocatalyst behaviour of Kish graphite recovered from polyethylene plastics

•For the first time, waste polyethylene was recycled into Kish graphite using an indigenous set-up.•The tafel studies show the anticorrosive nature with the corrosion potential of −1.6 V.•Mg-O2 battery with Kish graphite air cathode, shows long cell life and discharge capacity of 1226.51 mAh g−1.•Based on the ORR assessment, incorporation of Mn2O3 in KG was optimized for preferable four electron pathway. Polyethylene plastic is a threat to the environment because of its enormous usage and limited recycling options. Herewith, the study reports the synthesis of Kish graphite from polyethylene waste. These wastes was mixed with molten iron and cooled into a rod-shaped mold. The molded iron ingots contain precipitated carbon material in 2D graphitic nature, which was obtained as Kish graphite after several acid treatments. The tafel studies show the anticorrosive nature of the sample with the corrosion potential of −1.6 V. Kish graphite and manganese oxide in the ratio 40:9 exhibited higher catalytic activity towards oxygen reduction reaction. Discharge studies of Mg-air battery with graphite (80%) air cathode recorded the highest capacity of 1226.51 mAh g−1, discharge life of 73.6 h and enhanced performance characteristics. Thus, waste polyethylene was effectively used as an supportive electrocatalyst in the Mg-air battery system.