Hierarchically tubular architectures composed of vertical carbon nanosheets embedded with oxygen-vacancy enriched hollow Co₃O₄ nanoparticles for improved energy storage

Although great efforts have been devoted to exploiting electrode materials with designed composition and nanostructure for high-performance electrochemical energy storage devices, it remains critically challenging to achieve hierarchically tubular architectures constructed with different low-dimensional building blocks due to the lack of appropriate synthetic strategies. Herein, hierarchically tubular structures composed of vertically aligned carbon nanosheets embedded with oxygen-vacancy enriched hollow Co₃O₄ nanoparticles (H-Co₃O₄/C) are prepared. Benefited from these unique features, H-Co₃O₄/C electrode containing 54 wt.% carbon and 46 wt.% Co₃O₄ exhibits high specific capacity of 328.0 C g⁻¹ at 1 A g⁻¹, good rate capability with 70% capacity retained at 20 A g⁻¹, improved energy density of 8.3 Wh kg⁻¹ at the power density of 4268.5 W kg⁻¹ as well as remarkable stability for 10,000 charge-discharge cycles.