Journal of Power Sources 433 (2019) 126681
Available online 1 June 2019
0378-7753/© 2019 Elsevier B.V. All rights reserved.
New insights into the Li-storage mechanism in α-Ga
2
O
3
anode and the
optimized electrode design
Shibing Ni
a, *
, Qichang Chen
a
, Jilei Liu
b
, Shuyue Yang
a
, Tao Li
a
, Xuelin Yang
a, **
, Jinbao Zhao
c
a
College of Materials and Chemical Engineering, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, Key Laboratory of Inorganic Nonmetallic
Crystalline and Energy Conversion Materials, China Three Gorges University, Yichang, 443002, China
b
College of Materials Scienece and Engineering, Hunan University, Changsha, 410082, China
c
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, State-Province Joint Engineering
Laboratory of Power Source, Technology for New Energy Vehicle, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, PR China
HIGHLIGHTS G R A P H I C A L ABSTRACT
� New insights into Li-storage mechanism
of α-Ga
2
O
3
.
� Electrochemical performance optimiza-
tion via dual carbon decoration.
� Electrochemical reconstruction pro-
moted capacitive contribution for Li-
storage.
A R T I C L E INFO
Keywords:
Gallium oxide
Lithium ion storage mechanism
Conversion process
Alloying/dealloying
Anode
ABSTRACT
Fundamental insights into Li storage mechanism in α-Ga
2
O
3
allow manipulating materials with improved elec-
trochemical performance. Here, conversion reactions coupled with alloying/dealloying process are uncovered for
Li storage in α-Ga
2
O
3
anode, on the basis of ex-situ XRD, XPS, SAED and EDS mapping results. Specifcally, both
processes are part of irreversible. α-Ga
2
O
3
decorated with amorphous carbon and graphene (α-Ga
2
O
3
@C@G) and
nitrogen doping are successfully fabricated via a facile approach, showing distinctly improved performance
compared with pristine α-Ga
2
O
3
and α-Ga
2
O
3
decorated with graphene (α-Ga
2
O
3
@G). In the Ga
2
O
3
@C@G, dual
carbon improves the electronic conductivity and facilitates electrochemical reconstruction of the Ga
2
O
3
@C@G
upon cycling that renders high lithium ion diffusion, giving rise to enhanced capacitive contribution for lithium
storage. As a result, the Ga
2
O
3
@C@G exhibits high discharge/charge capacity of 458/447.3 mAh g
1
after 50
cycles at 0.1 A g
1
, with capacitive contribution of 59.2% for lithium ion storage at a scan rate of 1 mV s
1
.
1. Introduction
Lithium ion batteries (LIBs) have proven highly effcient energy
storage devices for power source dominating the portable electrics
market, as well as promising power supply for the coming electric ve-
hicles and smart grid storage systems [1–3]. However, the energy
* Corresponding author.
** Corresponding author.
E-mail addresses: shibingni07@126.com (S. Ni), xlyang@ctgu.edu.cn (X. Yang).
Contents lists available at ScienceDirect
Journal of Power Sources
journal homepage: www.elsevier.com/locate/jpowsour
https://doi.org/10.1016/j.jpowsour.2019.05.087
Received 5 April 2019; Received in revised form 20 May 2019; Accepted 25 May 2019