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SnP 2 O 7 Covered Carbon Nanosheets as a Long‐Life and High‐Rate Anode Material for Sodium‐Ion Batteries
Author(s) -
Pan Jun,
Chen Shulin,
Zhang Dapeng,
Xu Xuena,
Sun Yuanwei,
Tian Fang,
Gao Peng,
Yang Jian
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201804672
Subject(s) - materials science , pseudocapacitance , graphene , anode , sodium ion battery , transmission electron microscopy , sodium , chemical engineering , annealing (glass) , oxide , alloy , ion , composite number , analytical chemistry (journal) , electrode , nanotechnology , electrochemistry , composite material , metallurgy , supercapacitor , chemistry , chromatography , organic chemistry , faraday efficiency , engineering
SnP 2 O 7 attached to reduced graphene oxide (rGO) is synthesized by a solvothermal reaction, followed by a mild annealing in Ar/H 2 . As an anode material for sodium‐ion batteries, this composite is associated with the conversion reaction between Sn and SnP 2 O 7 and the alloy reaction between Sn and Na x Sn, as evidenced by ex situ techniques, such as high‐resolution transmission electron microscope images, selected area electron diffraction patterns, and X‐ray diffraction patterns. The close contact between SnP 2 O 7 and rGO facilitates the charge transfer upon cycling and benefits the preservation of SnP 2 O 7 on rGO even after pulverization. Therefore, this composite exhibits an extraordinary cycling stability. 99% of the initial capacity is remained after 200 cycles at 0.2 A g −1 and also 99% is kept after 1000 cycles at 1.0 A g −1 . The similar results are also observed in full cells. Quantitative kinetic analysis confirms that sodium storage in this composite is governed by pseudocapacitance, especially at high rates. These results indicate the promising potential of metal pyrophosphates in sodium‐ion batteries.