文献类型：期刊文献

英文题名：Revisiting Li+ intercalation into various crystalline phases of Nb2O5 anchored on graphene sheets as pseudocapacitive electrodes

作者：Kong, Lingping[1];Cao, Xiaodong[1];Wang, Jitong[1];Qiao, Wenming[1];Ling, Licheng[1];Long, Donghui[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2016

卷号：309

起止页码：42

外文期刊名：JOURNAL OF POWER SOURCES

收录：;EI(收录号：20160701945845);WOS:【SCI-EXPANDED(收录号:WOS:000371549100006)】；

基金：This work was partly supported by MOST (2014CB239702) and National Science Foundation of China (No. 21576090, No. 21506061, No. 51302083), and Fundamental Research Funds for the Central Universities (WA1516006) and Shanghai Rising Star Program (15QA1401300).

语种：英文

外文关键词：Niobium pentoxide; Graphene; Intercalation pseudocapacitance; Capacitive behavior; Li-ion diffusion coefficient

摘要：Herein, polycrystalline Nb2O5 nanoparticles including pseudo-hexagonal (TT-), orthorhombic (T-), tetragonal (M-) and monoclinic (H-) phases are uniformly anchored onto graphene sheets through a polyol-mediated solvothermal reaction and post heat-treatment, enabling us to discuss the effect of Nb2O5 crystalline phases on Li+ intercalation process. Electrochemical results show that Li+ intercalation into M- and H-Nb2O5 are also capacitive behavior, exhibiting higher capacity of 650 C g(-1) and 615 C than T- and TT-phases of 585 C g(-1) and 530 C g(-1) at 0.5 A g(-1). The higher capacity-retention is also obtained for M- and H-phases (509 and 452 C g(-1)) compared to T- and TT-phases (305 and 207 C g(-1)) at 20 A The high rate performance of H-phase can be explained by higher Li+ diffusion coefficients (D-Li) of 1.6 x 10(-12) cm(2) s(-1), which is almost two order of magnitude higher than TT-phase of 4.7 x 10(-14) cm(2) s(-1). This results indicate that Nb2O5 with various crystal structures shows similar Li+ capacitive intercalation behavior, but more ordered arrangement of unit cell may provide more vacancy for Li+ with the lower diffusion barriers, thus leading to higher rate performance. (C) 2016 Elsevier B.V. All rights reserved.