Heterostructure Necklace-like NiO-NiCo2O4 Hybrid with Superior Catalytic Capability as Electrocatalyst for Li-O2 Batteries

Zeinab Mohamed,1,2  

Guoliang Zhang,2  

Biao He 3*Email

Yuqi Fan1*Email

1Institute of Environment and Ecology, Shandong Normal University, Jinan, 250014, China

2Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 17923 Jingshi Road, Jinan 250061, China

3Institute for Materials, Ruhr-Universität Bochum, Universitätsstr. 150, 44803 Bochum, Germany

Abstract

The advancement of the Li-O2 battery is still in its beginning stages. Heterostructure composites, especially transition-metal oxide-based materials, were proved as efficient electrocatalysts which can significantly improve the sluggish reaction efficiency and battery performance. This research aimed to synthesize and investigate the bi-functional NiO-NiCo2O4 microspheres as a cathode in aprotic Li-O2 batteries for boosting electrochemical efficiency utilizing a simple hydrothermal method and annealing. Based on the existing electrochemical features of NiO-NiCo2O4 catalysts, the unique hybrid structure and dynamical impact between the nickel cobaltite and nickel oxide phases may support and promote electro-catalysis. NiCo2O4 helps enhance oxygen reduction and evolution reactions at the positive electrode, as well as NiO probably promotes the degradation of some by-products. In addition, the unique necklace-like morphology leads to continuing oxygen flowing, storing the discharge products, and boosting the transportation of ions and electrons. A substantial capacity of 23163/20770 mAh g-1 was achieved, and the overpotential of 0.13/0.61 V was minimized in discharge/charge. Moreover, the positive electrode can hold the cycle more than 170 times without any apparent variation at a current 200 mA g-1, indicating that the as-synthesized necklace-like hetero structure NiO-NiCo2O4 is an interesting driving force cathode catalyzer for Li-O2 batteries.

Heterostructure Necklace-like NiO-NiCo2O4 Hybrid with Superior Catalytic Capability as Electrocatalyst for Li-O2 Batteries