J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (10): 2396-2403.DOI: 10.1016/j.jmst.2019.06.002

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In situ fabrication of Na3V2(PO4)3 quantum dots in hard carbon nanosheets by using lignocelluloses for sodium ion batteries

Qihao Zhanga, Xudong Zhanga*(), Wen Hea*(), Guogang Xub, Manman Rena, Jinhua Liua, Xuena Yanga, Feng Wanga   

  1. aInstitute of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
    bCollege of Material Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China
  • Online:2019-10-05 Published:2019-08-28
  • Contact: Zhang Xudong,He Wen

Abstract:

The rational assembly of quantum dots on two-dimensional (2D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3V2(PO4)3 quantum dots with superlattice structure (NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses (LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets (HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 mA h g-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3V2(PO4)3 (117.6 mA h g-1). At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 mA h g-1. Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained, highlighting its excellent long cycling life, remarkable rate performance and energy density.

Key words: Lignocellulose, Hard carbon nanosheet, Na3V2(PO4)3 quantum dot, Superlattice structure