Modulating the d-Band Center of RuO2 via Ni Incorporation for Efficient and Durable Li-O2 batteries.

ABSTRACT

Rechargeable Li-O2 batteries (LOBs) are considered as one of the most promising candidates for new-generation energy storage devices. One of major impediments is the poor cycle stability derived from the sluggish reaction kinetics of unreliable cathode catalysts, hindering the commercial application of LOBs. Therefore, the rational design of efficient and durable catalysts is critical for LOBs. Optimizing surface electron structure via the negative shift of the d-band center offers a reasonable descriptor for enhancing the electrocatalytic activity. In this study, the construction of Ni-incorporating RuO2 porous nanospheres is proposed as the cathode catalyst to demonstrate the hypothesis. Density functional theory calculations reveal that the introduction of Ni atoms can effectively modulate the surface electron structure of RuO2 and the adsorption capacities of oxygen-containing intermediates, accelerating charge transfer between them and optimizing the growth pathway of discharge products. Resultantly, the LOBs exhibit a large discharge specific capacity of 19658 mA h g-1 at 200 mA g-1 and extraordinary cycle life of 791 cycles. This study confers the concept of d-band center modulation for efficient and durable cathode catalysts of LOBs.