3D Ag/NiO-Fe2O3/Ag nanomembranes as carbon-free cathode materials for Li-O2 batteries

The Li-O-2 battery is considered as an appealing candidate for future energy supplies due to its exceptionally high energy density. A key issue of prevailing aprotic Li-O-2 batteries is exploring carbon-free electrode materials to avoid the irreversible side reactions produced by carbonaceous electrode. Here, three-dimensional (3D) curved Ag/NiO-Fe2O3/Ag hybrid nanomembranes induced by a facile thermal treatment method are fabricated, for the first time, as carbon-free cathode materials in Li-O-2 batteries. A competing scheme between the intrinsic strain built in the oxide nanomembranes and the external driving force provided by the metal nanoparticles is introduced to tune the morphology of the 3D tubular architectures. The tubular structure of the nanomembranes provides continuous tunnels for the diffusion of O-2 and electrolyte as well as the accommodation of discharge products without clogging. More importantly, the side reactions are effectively mitigated by such carbon-free nanomembrane materials. Therefore, enabled by such 3D hybrid nanomembranes with particularly interesting morphology and structure, the Li-O-2 batteries exhibit enhanced electrochemical performance with low overvoltages, high capacity retention and greatly prolonged cycle life.