Granular molybdenum dioxide precipitated on N-doped carbon nanorods with multistage architecture for ultralong-life sodium-ion batteries

• Published in: Electrochimica acta 2019-12, Vol.325, p.134903, Article 134903
• Main Authors: Zeng, Fanyan, Yang, Leyan, Pan, Yang, Xu, Meng, Liu, Hongyan, Yu, Maohui, Guo, Manman, Yuan, Cailei
• Format: Article
• Language: English
• Subjects: Aniline; Anodes; Architecture; Diffusion length; Dioxides; Electrical resistivity; Electrode materials; Electrodes; Electron diffusion; In-situ phase transformation; Ion storage; Molybdenum; Molybdenum oxides; Multistage; N-doped carbon nanorods; Nanorods; Particulate composites; Phase transitions; Precipitates; Reaction kinetics; Rechargeable batteries; Sodium-ion batteries; Transition metal oxides; Ultra-long cycling stability
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.134903

Developing high-performance anode materials is a crucial research target of sodium-ion batteries (SIBs). Transition metal oxides (TMOs) have attracted great interest as potential anodes, but their applications are still hindered by slow reaction kinetics and large volume changes. Herein, Mo-aniline nanorods (Mo-ANRs) are prepared as precursors by a simple self-polymerized method in acid condition. After the in-situ phase transformation during annealing, multistage composites (N-CNRs@g-MoO2) are formed, with N-doped carbon nanorods (N-CNRs) converted from polymeric aniline ligands, on which granular molybdenum dioxide (g-MoO2) are uniformly precipitated and residual MoO2 nanodots are remained. As anode materials for SIBs, N-CNRs@g-MoO2 electrode is benefited from the shortened ion/electron diffusion length caused by steady g-MoO2 and residual nanodots, and the enhanced electrical conductivity and relieved volume changes introduced by N-CNRs and unique architecture. Thus, N-CNRs@g-MoO2 electrode delivers high discharge capacity (497.5 mAh g−1 at 0.05 A g−1), excellent rate performance and ultra-long cycling stability (165.6 mAh g−1 at 10.0 A g−1 after 12000 cycles), and 122% capacity retention is obtained at 1.0 A g−1 over 500 cycles even after the rate test. The significant enhancements in sodium-ion storage are mainly attributed to the multistage architecture and synergistic advantages among MoO2 nanodots, N-CNRs and g-MoO2. These results indicate that the in-situ phase transformation route has great potential in constructing novel composites with unique architecture for high-performance SIBs. A Mo-aniline-derived N-CNRs@g-MoO2 composites with multistage architecture are constructed by in-situ phase transformation route. The composites exhibit excellent sodium-ion storage performance due to the synergistic effects among MoO2 nanodots, N-CNRs and g-MoO2. Importantly, the ultra-long cyclic stability is acquired at high current rates (218.2 mAh g−1 at 5.0 A g−1 after 5000 cycles and 165.6 mAh g−1 at 10.0 A g−1 after 12000 cycles). [Display omitted] •Mo-ANRs are self-polymerized from MoO42+ anions and aniline under acid solution.•Multistage architectures of N-CNRs@g-MoO2 is constructed by in-situ phase transformation route.•g-MoO2 are precipitated on N-CNRs and residual MoO2 nanodots are embedded in N-CNRs.•N-CNRs@g-MoO2 deliver extraordinary rate capability and ultra-long cyclic stability (12000 cycles).