Crystal Structure Modification Enhanced FeNb 11 O 29 Anodes for Lithium‐Ion Batteries
Abstract The recently explored FeNb 11 O 29 is an advanced anode material for lithium‐ion batteries, owing to its high specific capacity and safety. However, it suffers from poor rate capability. To tackle this issue, a crystal structure modification is employed. Defective FeNb 11 O 29 (FeNb 11 O 27...
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Published in | ChemElectroChem Vol. 4; no. 12; pp. 3171 - 3180 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.12.2017
|
Online Access | Get full text |
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Summary: | Abstract
The recently explored FeNb
11
O
29
is an advanced anode material for lithium‐ion batteries, owing to its high specific capacity and safety. However, it suffers from poor rate capability. To tackle this issue, a crystal structure modification is employed. Defective FeNb
11
O
29
(FeNb
11
O
27.9
) is fabricated by using a one‐step solid‐state reaction method in N
2
. FeNb
11
O
27.9
has the same orthorhombic shear ReO
3
crystal structure (
Amma
space group) as FeNb
11
O
29
, but a larger unit‐cell volume and 3.8 % O
2−
vacancies (vs. all O
2−
ions), which improve the Li
+
‐ion diffusion coefficient by a factor of 88.3 %. The contained Nb
4+
ions with free 4
d
electrons significantly increase the electronic conductivity by three orders of magnitude. Consequently, FeNb
11
O
27.9
shows improved pseudocapacitive behavior and electrochemical properties. In comparison with FeNb
11
O
29
, FeNb
11
O
27.9
exhibits a higher reversible capacity of 270 mAh g
−1
with a higher first‐cycle coulombic efficiency of 90.6 % at 0.1 C. At 10 C, FeNb
11
O
27.9
still retains a high capacity of 145 mAh g
−1
with low capacity loss of 6.9 % after 200 cycles, in contrast to the values of 99 mAh g
−1
and 11.1 % obtained for FeNb
11
O
29
. |
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ISSN: | 2196-0216 2196-0216 |
DOI: | 10.1002/celc.201700816 |