Browsing by Author "Chen, MZ"

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    Development and investigation of a NASICON‐type high‐voltage cathode material for high‐power sodium‐ion batteries
    (Wiley, 2020-02-03) Chen, MZ; Hua, WB; Xiao, J; Cortie, DL; Guo, XD; Wang, E; Gu, QF; Hu, Z; Indris, S; Wang, XL; Chou, SL; Dou, SX
    Herein, we introduce a 4.0 V class high‐voltage cathode material with a newly recognized sodium superionic conductor (NASICON)‐type structure with cubic symmetry (space group P213), Na3V(PO3)3N. We synthesize an N‐doped graphene oxide‐wrapped Na3V(PO3)3N composite with a uniform carbon coating layer, which shows excellent rate performance and outstanding cycling stability. Its air/water stability and all‐climate performance were carefully investigated. A near‐zero volume change (ca. 0.40 %) was observed for the first time based on in situ synchrotron X‐ray diffraction, and the in situ X‐ray absorption spectra revealed the V3.2+/V4.2+ redox reaction with high reversibility. Its 3D sodium diffusion pathways were demonstrated with distinctive low energy barriers. Our results indicate that this high‐voltage NASICON‐type Na3V(PO3)3N composite is a competitive cathode material for sodium‐ion batteries and will receive more attention and studies in the future. © 2019Wiley-VCHVerlagGmbH&Co
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    Development and investigation of a NASICON‐type high‐voltage cathode material for high‐power sodium‐ion batteries
    (Wiley, 2020-02-03) Chen, MZ; Hua, WB; Xiao, J; Cortie, DL; Guo, XD; Wang, E; Gu, QF; Hu, Z; Indris, S; Wang, XL; Chou, SL; Dou, SX
    Herein, we introduce a 4.0 V class high‐voltage cathode material with a newly recognized sodium superionic conductor (NASICON)‐type structure with cubic symmetry (space group P213), Na3V(PO3)3N. We synthesize an N‐doped graphene oxide‐wrapped Na3V(PO3)3N composite with a uniform carbon coating layer, which shows excellent rate performance and outstanding cycling stability. Its air/water stability and all‐climate performance were carefully investigated. A near‐zero volume change (ca. 0.40 %) was observed for the first time based on in situ synchrotron X‐ray diffraction, and the in situ X‐ray absorption spectra revealed the V3.2+/V4.2+ redox reaction with high reversibility. Its 3D sodium diffusion pathways were demonstrated with distinctive low energy barriers. Our results indicate that this high‐voltage NASICON‐type Na3V(PO3)3N composite is a competitive cathode material for sodium‐ion batteries and will receive more attention and studies in the future. Copyright © 1999-2024 John Wiley & Sons, Inc or related companies.
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    A novel graphene oxide wrapped Na2Fe2(SO4)3/C cathode composite for long life and high energy density sodium‐ion batteries
    (Wiley, 2018-08-06) Chen, MZ; Cortie, DL; Hu, Z; Jin, H; Wang, S; Gu, QF; Hua, WB; Wang, E; Lai, WH; Chen, L; Chou, SL; Wang, XL; Dou, SX
    The cathode materials in the Na‐ion battery system are always the key issue obstructing wider application because of their relatively low specific capacity and low energy density. A graphene oxide (GO) wrapped composite, Na2Fe2(SO4)3@C@GO, is fabricated via a simple freeze‐drying method. The as‐prepared material can deliver a 3.8 V platform with discharge capacity of 107.9 mAh g−1 at 0.1 C (1 C = 120 mA g−1) as well as offering capacity retention above 90% at a discharge rate of 0.2 C after 300 cycles. The well‐constructed carbon network provides fast electron transfer rates, and thus, higher power density also can be achieved (75.1 mAh g−1 at 10 C). The interface contribution of GO and Na2Fe2(SO4)3 is recognized and studied via density function theory calculation. The Na storage mechanism is also investigated through in situ synchrotron X‐ray diffraction, and pseudocapacitance contributions are also demonstrated. The diffusion coefficient of Na+ ions is around 10−12–10−10.8 cm2 s−1 during cycling. The higher working voltage of this composite is mainly ascribed to the larger electronegativity of the element S. The research indicates that this well‐constructed composite would be a competitive candidate as a cathode material for Na‐ion batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA.