Highly porous structured Sr-doped La2NiO4/NiO composite cathode with interconnected pores for lithium-oxygen batteries

Abstract

• Highly porous OP-SLNO was prepared by one-pot spray pyrolysis. • OP-SLNO showed improved catalytic abilities for both OER and ORR. • OP-SLNO with interconnected pores was suitably applied to Li-O 2 batteries. • Interconnected pores provided space to accommodate abundant discharge products. One-pot spray pyrolysis process is a promising continuous process for mass production of nanostructured powder. The highly porous microspheres containing pores interconnected from the inner to the outer side of particle are prepared by one-pot spray pyrolysis process. In this study, Sr-doped layered perovskite oxide is selected as the first target material. A colloid comprising mono-sized spherical templates were used as a precursor to synthesize the porous Sr-doped La 2 NiO 4 /NiO composite powder. The fine and spherical templates construct a highly open and porous structure throughout the resulting particle’s inner bulk and surfaces. The fabricated powder shows improved catalytic abilities for both OER and ORR, based on the results of the RDE measurements. Owing to the open-pore structure, the overpotentials for both discharge and charge processes are lowered attributing to extremely improved cycle life of over 180 cycles when applied to Li-O 2 cell, while the filled-structured powder gives less than 50 cycles. Furthermore, the Li-O 2 cell reveals definitely improved discharge capacity of 13,130 mA h g −1 under 200 mA g −1 owing to the interconnected pore structure, when compared to discharge capacities of closed-pores-containing powder (9,547 mA h g −1 ) and filled-structured powder (7,541 mA h g −1 ).