Hierarchical NiCo2S4@NiO Core–Shell Heterostructures as Catalytic Cathode for Long‐Life Li‐O2 Batteries. Issue 24 (9th May 2019)

• Record Type: Journal Article
• Authors: Wang, Peng; Li, Caixia; Dong, Shihua; Ge, Xiaoli; Zhang, Peng; Miao, Xianguang; Wang, Rutao; Zhang, Zhiwei; Yin, Longwei
• Is Part Of: Advanced energy materials. Volume 9:Issue 24(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-05-09
• Subjects: cathodes -- heterostructures -- Li2O2 -- lithium–oxygen batteries -- oxygen reduction reaction; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201900788
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: The critical challenges of Li‐O2 batteries lie in sluggish oxygen redox kinetics and undesirable parasitic reactions during the oxygen reduction reaction and oxygen evolution reaction processes, inducing large overpotential and inferior cycle stability. Herein, an elaborately designed 3D hierarchical heterostructure comprising NiCo2 S4 @NiO core–shell arrays on conductive carbon paper is first reported as a freestanding cathode for Li‐O2 batteries. The unique hierarchical array structures can build up multidimensional channels for oxygen diffusion and electrolyte impregnation. A built‐in interfacial potential between NiCo2 S4 and NiO can drastically enhance interfacial charge transfer kinetics. According to density functional theory calculations, intrinsic LiO2 ‐affinity characteristics of NiCo2 S4 and NiO play an importantly synergistic role in promoting the formation of large peasecod‐like Li2 O2, conducive to construct a low‐impedance Li2 O2 /cathode contact interface. As expected, Li‐O2 cells based on NiCo2 S4 @NiO electrode exhibit an improved overpotential of 0.88 V, a high discharge capacity of 10 050 mAh g −1 at 200 mA g −1, an excellent rate capability of 6150 mAh g −1 at 1.0 A g −1, and a long‐term cycle stability under a restricted capacity of 1000 mAh g −1 at 200 mA g −1 . Notably, the reported strategy about heterostructure accouplement may pave a new avenue for the effective electrocatalyst design for Li‐O2 batteries. Abstract : An elaborately designed 3D hierarchical NiCo2 S4 @NiO core–shell heterostructure with dendritic morphology on carbon paper is first reported as a freestanding cathode for Li‐O2 batteries. The NiCo2 S4 @NiO heterointerfaces with a striking built‐in interfacial electric potential play a key role in boosting interfacial electron transfer. Different intrinsic LiO2 ‐affinity characteristics of NiCo2 S4 and NiO modulate crystallization behavior of Li2 O2 during the oxygen reduction reaction process.