摘要
The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(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 Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A 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.
The rational assembly of quantum dots on two-dimensional（2 D） carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2（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 Na3 V2（PO4）3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2（PO4）3(117.6 m A h g-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A 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.
基金
supported financially by the National Natural Science Foundation of China (Nos. 51672139, 51472127 and 51272144)
the Projects Supported by the Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education (No. KF2016-01)
