A new type of sealed rechargeable lithium–lithium oxide battery based on reversible LiO2/Li2O2 interconversion

Abstract

We report in this letter a new type of sealed rechargeable lithium–lithium oxide battery based on reversible interconversion between superoxide (LiO₂) and lithium peroxide (Li₂O₂). A free-standing oxygenated group-rich reduced graphene oxide aerogel (OR-rGO) with decent mechanical properties is prepared through a hydrothermal method followed by slight drying in air at room temperature and applied as a cathode in oxygen-based beyond-intercalation Li batteries. In situ Raman spectroscopy, online electrochemical mass spectroscopy, and density functional theory calculations revealed the reversible stabilization of LiO₂ by the oxygenated groups on rGO during the charge process. Based on the stability of LiO₂ on oxygenated group-rich reduced graphene oxide, a new sealed lithium–lithium oxide battery via reversible Li₂O₂/LiO₂ interconversion was realized with high operating potential up to 3.65 V and no O₂ evolution. Excellent cycling stability was observed for 700 cycles at a cut-off capacitance of 0.6 mA h cm⁻² and a current density of 0.6 mA cm⁻².