Abstract
A sustainable cathode is critical to developing green lithium storage devices. Conducting polymers, radical polymers and carbonyl-based polymers are the three most important types of polymer-based sustainable cathode materials. Here we report that graphene oxide enriched with epoxide, without being reduced, is a promising sustainable carbonaceous cathode material for rechargeable lithium storage. Graphene oxide containing a large quantity of epoxide can have a high capacity of 360.4 mA h g(-1) at 50 mA g(-1), which significantly surpasses those of many polymer cathodes and conventional lithium-transition metal oxide cathodes. The good stability of this epoxide-based cathode was demonstrated. Density functional theory calculations indicate that the lithiation of epoxide is energetically favorable (-1.21 eV) and the original epoxide structure can be restored after delithiation with a small barrier (0.23 eV).