Constructing hierarchical MoO2/N-doped carbon hydrangea-like spheres with superior lithium storage properties

The increasing demand for renewable energy boosts the exploration of energy conversion and storage devices, which to a large extent depends on the development of reliable electrode materials. In this work, hierarchically-structured MoO2/N-doped carbon hydrangea-like spheres (designated as MoO2/N-C thereafter) self-assembled from mesoporous nanosheets are successfully prepared via a facile hydrothermal reaction and a subsequent annealing process. Benefiting from the hierarchically mesoporous architecture, nanosheet configuration, and electrically conductive carbon matrix, the hydrangea-like MoO2/N-C spheres possess favorable electrochemical features including sufficient electrode/electrolyte interfacial areas, shortened ion diffusion length, and promoted reaction kinetics. Accordingly, the MoO2/N-C hybrid shows excellent electrochemical performance, delivering a large specific capacity of 899 mAh g(-1) with an initial Coloumbic efficiency as high as 82.9% as well as long-term cycling performance. In addition, outstanding rate capability can be achieved with a high capacity retention of 400 mAh g(-1) at 2000 mA g(-1), which substantially outperforms that of the commercial MoO2 nanoparticles. The present study suggests the great potential of MoO2/N-C spheres as high-performance electrode materials for advanced energy storage applications. (C) 2019 Elsevier B.V. All rights reserved.