One-Dimensional MnO2 Nanowires Space-Confined in Hollow Mesoporous Carbon Nanotubes for Enhanced Zn2+ Storage Performance

The yolk-shell structure exhibits fascinating and important properties for energy storage devices. The carbon shell significantly improves the good electrical conductivity and the stable micro-/nanostructures of the active material increases utilization. MnO2@C with a yolk-shell structure shows high reversibility, good rate performance, and excellent cycling stability for aqueous Zn-ion batteries. The Zn-ion battery with MnO2@C could realize a high reversible capacity of 239 mAh g(-1) at 0.1 A g(-1). In particular, at a quite high current density of 2 A g(-1), it achieves capacity of 91 mAh g(-1). The Zn-ion battery has excellent capacity retention of up to 1000 cycles at 1 A g(-1). The yolk-shell structure plays an important role in improving the battery performance.