Full paperSelf-adaptive mesoporous CoS@alveolus-like carbon yolk-shell microsphere for alkali cations storage

- Developing a self-sacrificing generated void space method to synthesize a unique yolk-shell mesoporous-CoS@C microsphere.
- Mesoporous-CoS@C contains mesoporous CoS yolk and alveolus-like carbon shell.
- Mesoporous-CoS@C electrode shows impressive cycling stability and excellent rate capability for both Li+ and Na+ storage.

To address the severe volume changes of transition metal chalcogenides that results in inferior cycling performance, herein, a unique yolk-shell microsphere composed of mesoporous cobalt sulfide yolk and alveolus-like carbon shell (M-CoS@C) is constructed. The mesoporous CoS yolks possess large surface area (46.3 m2 g−1) accompanied with the interconnected mesoporous structure, which provide a large contact area to facilitate the permeation of the electrolyte and shorten the ion diffusion path. The alveolus-like carbon shells provide enough void spaces and highly self-adaptive structure to ensure the high stability of the electrode. Owing to the multifunctionality of this unique structure, the M-CoS@C electrode shows impressive cycling stability (790 mA h g−1 after 500 cycles at 1 A g−1 for Li-storage, 532 mA h g−1 after 100 cycles at 0.2 A g−1 for Na-storage) and excellent rate capability (330 mA h g−1 at 20 A g−1 for Li-storage, 190 mA h g−1 at 20 A g−1 for Na-storage). This unique mesoporous yolks@alveolus-like carbon shell structure and the self-sacrificing synthesis method present the effective strategies to promote the utilization of transition metal chalcogenides for practical applications.

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