Discarded lithium ion batteries transformed into rGO-based supercapacitors

Scientists from CSIRCentral Electrochemical Research Institute (CSIR-CECRI) and CSIRCentral Salt and Marine Chemicals Research Institute (CSIR-CSMCRI) in India have collected discarded lithium-ion batteries and created reduced graphene oxide from them. The material reportedly showed high specific capacity at low current, making it an ideal material for next generation high-performance supercapacitors.

The specific capacity was found to be 112 farad per gram from fundamental evaluation, which is almost equal to the commercially available ones. Also the ones available in market today are created using activated carbon which is expensive and environmentally hazardous while our method is cheaper and fully environmental friendly explains the team.

The new rGO-based electrodes showed high stability even after 20,000 cycles. They also had high retention capacity where 70% of the efficiency was retained even after 85 cycles. The efficiency slowly increased and reached 108% after 20,000 cycles. The long-term stability and robustness of the capacitor are the key parameters for qualifying as suitable candidates for commercial application.

Today lithium-ion batteries are used widely and disposed after they run out, leading to mounting e-waste. We tried a new method and succeeded in recycling and reusing these batteries, says the team. The graphite anode and aluminium and stainless steel from dismantled batteries were used. The graphite was converted into graphene oxide by oxidation and subsequent exfoliation. Graphene oxide was further reduced to reduced graphene oxide.

We are further evaluating the capacitive nature of our prepared electrode in two electrode system and hope to bring it out soon for large scale commercial applications, says the CSIR-CSMCRI team.