Figure 5.

(A) The cycling performance of NiCo₂S₄ and rGO–NiCo₂S₄ at 50 mA g⁻¹. (B) Schema of Na-ion insertion process in NiCo₂S₄ and rGO–NiCo₂S₄. Reproduced with permission from Zhang et al. (2018) Copyright 2018. Royal Society of Chemistry. (C) Cycling performances of (Ni,Co)O-rGO and Ni₃Co₆S₈- rGO at 0.5 A g⁻¹. Reproduced with permission from Choi and Kang (2015a) Copyright 2015. Royal Society of Chemistry. (D) SEM images of NiCo₂S₄-NC, (E) Cycling performances of NiCo₂S₄-NC in different electrolytes at 1.0 A g⁻¹, (F) Cycling performance and coulombic efficiency of NiCo₂S₄-NC in different cut-off voltage windows at 0.2 A g⁻¹. Reproduced with permission from Li S. et al. (2019) Copyright 2019. Elsevier.