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Hierarchical NiCo 2 S 4 @NiO Core–Shell Heterostructures as Catalytic Cathode for Long‐Life Li‐O 2 Batteries
Author(s) -
Wang Peng,
Li Caixia,
Dong Shihua,
Ge Xiaoli,
Zhang Peng,
Miao Xianguang,
Wang Rutao,
Zhang Zhiwei,
Yin Longwei
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201900788
Subject(s) - overpotential , non blocking i/o , materials science , cathode , heterojunction , electrocatalyst , chemical engineering , electrolyte , nanoclusters , catalysis , electrochemistry , nanotechnology , electrode , chemistry , optoelectronics , biochemistry , engineering
Abstract The critical challenges of Li‐O 2 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 NiCo 2 S 4 @NiO core–shell arrays on conductive carbon paper is first reported as a freestanding cathode for Li‐O 2 batteries. The unique hierarchical array structures can build up multidimensional channels for oxygen diffusion and electrolyte impregnation. A built‐in interfacial potential between NiCo 2 S 4 and NiO can drastically enhance interfacial charge transfer kinetics. According to density functional theory calculations, intrinsic LiO 2 ‐affinity characteristics of NiCo 2 S 4 and NiO play an importantly synergistic role in promoting the formation of large peasecod‐like Li 2 O 2 , conducive to construct a low‐impedance Li 2 O 2 /cathode contact interface. As expected, Li‐O 2 cells based on NiCo 2 S 4 @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‐O 2 batteries.