Researchers have developed an eco-friendly technique for producing graphene from discarded lithium-ion batteries. Such graphene made from spent batteries could potentially be used to make efficient supercapacitors1.
Lithium-ion batteries are widely used in portable electronic devices such as mobile phones and laptops. When such batteries run out of fuel, they are disposed of as electronic waste, generating pollutants that are harmful to human health and the environment.
To stop such battery-derived pollutant generation, scientists from the CSIR–Central Electrochemical Research Institute in Tamilnadu and CSIR–Central Salt and Marine Chemicals Research Institute in Gujarat invented a simple process that can generate reduced graphene oxide from graphite isolated from spent lithium-ion batteries.
Graphene oxide made from the graphite was converted into reduced graphene oxide using the iron and aluminium present in the metallic cover of the batteries and acid. The reduced graphene oxide had sheet-like structures with wrinkles and scrolls on the surface.
Electrodes made of the reduced graphene oxide displayed efficiencies to store charge – an interesting property for making supercapacitors. When exposed to 20,000 cycles of charging and discharging at a high current density, one of the electrodes retained 70% of its efficiency for storing a charge up to 85 cycles. This efficiency began to rise and reached almost 108% after 85 cycles.
The process is faster and cheaper than other methods for generating reduced graphene oxide at lower temperatures, showing its potential for making materials for fabricating next-generation high-performance supercapacitors.
