(603d) Durable High Capacity Li-O2 Cathode Composed of Iron-Nitrogen-Doped Mesoporous Core-Shell Carbon Loaded with RuO2 Nanoparticles

The reversible lithium oxygen battery has generated a lot of interests for its high energy density. Limitations of oxygen reduction and evolution (ORR/OER) kinetics in aprotic solvents, lack of reversible lithium peroxide deposition/dissolution, and degradation problems have hintered development of Li-O₂ technology. There are few reports of durable high capacity cathode performance. Nitrogen-doped mesoporous carbon has been succesfully deployed for ORR in aqueous electrolytes[1]. Here, we report Fe-N-doped hierarchical mesoporous carbon loaded with RuO₂ nanoparticles (Fe-N-HCMS-RuO₂) for application as a Li-O₂ cathode. Promising results are observed with capacity reaching 1/3 the theoretical energy density of Li-O₂ (3,500 Wh/kg). The Fe-N-HCMS-RuO₂ electrode demonstrates excellent performance which can be attributed to three features of the composite. A well-defined core-shell mesoporous structure provides excellent mass transport and limits the Li₂O₂ deposition to be dispersed in nanoscale. The Fe-N doping of carbon provides the corrosion resistance, high conductivity, and active sites for favorable interaction with RuO₂. Small and amorphous RuO₂ provides highly catalytic activity for decomposition of Li₂O₂. Discharge capacity of 10,000 mAh/g is demonstrated with discharge potential of 2.4 V and recharge potential of 3.6 V maintained at 2 A/g based on total mass of catalyst and carbon support and maintained at 2.5 V and 3.5 V at 1 A/g over 50 cycles.