Self-assembling RuO2 nanogranulates with few carbon layers as an interconnected nanoporous structure for lithium–oxygen batteries

Abstract

Electrocatalysis for cathodic oxygen is of great significance for achieving high-performance lithium–oxygen batteries. Herein, we report a facile and green method to prepare an interconnected nanoporous three-dimensional (3D) architecture, which is composed of RuO₂ nanogranulates coated with few layers of carbon. The as-prepared 3D nanoporous RuO₂@C nanostructure can demonstrate a high initial specific discharge capacity of 4000 mA h g⁻¹ with high round-trip efficiency of 95%. Meanwhile, the nanoporous RuO₂@C could achieve stable cycling performance with a fixed capacity of 1500 mA h g⁻¹ over 100 cycles. The terminal discharge and charge potentials of nanoporous RuO₂@C are well maintained with minor potential variation of 0.14 and 0.13 V at the 100th cycle, respectively. In addition, the formation of discharge products is monitored by using in situ high-energy synchrotron X-ray diffraction (XRD).