Short communication
High areal capacity, micrometer-scale amorphous Si film anode based
on nanostructured Cu foil for Li-ion batteries
Wenping Si
a, b, *
, Xiaolei Sun
a, b
, Xianghong Liu
a
, Lixia Xi
c
, Yandong Jia
c
,
Chenglin Yan
a, d, *
, Oliver G. Schmidt
a, b, e, f
a
Institute for Integrative Nanosciences, IFW Dresden, Helmholtz Strasse 20, Dresden, 01069, Germany
b
Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Strasse 70, Chemnitz, 09107, Germany
c
Institute for Complex Materials, IFW Dresden, Helmholtz Strasse 20, Dresden, 01069, Germany
d
School of Energy, Soochow University, Suzhou, Jiangsu, 215006, China
e
Center for Advancing Electronics Dresden, Dresden University of Technology, Germany
f
Merge Technologies for Multifunctional Lightweight Structures, Chemnitz University of Technology, Germany
highlights graphical abstract
Nanostructured Cu foil is prepared by
anodic oxidation for thick Si film
loading.
Copper oxide nanofibers are in-situ
electrochemically reduced to
metallic Cu.
Metallic Cu nanofibers work as ma-
trix for thick Si film.
The engineered thick Si film anode
exhibits a high areal capacity.
article info
Article history:
Received 26 March 2014
Received in revised form
17 May 2014
Accepted 27 May 2014
Available online 5 June 2014
Keywords:
Micrometer-scale silicon film
Li-ion battery
High areal capacity
Copper oxide nanofiber
Anode
abstract
We report a feasible design to fabricate micrometer-scale Si films deposited on nanostructured Cu foil as
high areal capacity anodes for Li-ion batteries with excellent cycling performance. Nanostructured
copper oxides are prepared by anodic oxidation of Cu foil in alkaline solution. The resultant copper oxide
nanofibers function as matrix for thick Si films (1e2 mm) loading. Metallic Cu nanofibers are obtained by
in-situ electrochemical reduction at low potentials, which work as electrical highways for fast electron
transport and a reliable mechanical matrix to accommodate volume changes during lithiumesilicon
alloy/dealloy processes. The engineered thick Si film anode exhibit both high areal capacity
(0.48 mAh cm
2
for 1 mm Si film and 0.6 mAh cm
2
for 2 mm Si film after 200 cycles at 0.225 mA cm
2
)
and excellent rate capability (0.52 mAh cm
2
at 1.05 mA cm
2
for 2 mm Si film). The 2 mm silicon film
electrode is able to recover to the initial value of 1 mAh cm
2
when the current rate is set back to
0.15 mA cm
2
even after cycling at high current rates. The reported concept can be a general method for
high-loading-film electrodes, which is industrial scalable and compatible with current battery
manufacturing processes.
© 2014 Elsevier B.V. All rights reserved.
1. Introduction
Silicon, as an attractive candidate for Li-ion batteries (LIBs) an-
odes, has high theoretical capacity (3579 mAh g
1
at room tem-
perature for Li
3.75
Si) [1e5], but a very large volume expansion
* Corresponding authors. Institute for Integrative Nanosciences, IFW Dresden,
Helmholtz Strasse 20, Dresden, 01069, Germany. Tel.: þ49 351 4659 869; fax: þ49
351 4659 782.
E-mail addresses: w.si@ifw-dresden.de, siwp86@gmail.com (W. Si), c.yan@ifw-
dresden.de (C. Yan).
Contents lists available at ScienceDirect
Journal of Power Sources
journal homepage: www.elsevier.com/locate/jpowsour
http://dx.doi.org/10.1016/j.jpowsour.2014.05.136
0378-7753/© 2014 Elsevier B.V. All rights reserved.
Journal of Power Sources 267 (2014) 629e634