(414a) A Self-Supported and Long-Life Li-Se Battery Cathode Enabled By 3D Mesoporous Carbon/Graphene Hierarchical Architecture

For 2015 AIChE Annual Meeting

Topical 5: Nanomaterials for Energy Applications

Session: Nanomaterials for Energy Storage

A Self-supported and Long-life Li-Se Battery Cathode Enabled by 3D
Mesoporous Carbon/Graphene Hierarchical Architecture

Kai, Han*, Central
South University (China)      hankai@csu.edu.cn

Heng, Jiang,
Central South University (China)      Hongqi, Ye,
Central South University (China)

Zhao, Liu, Northwestern University
(USA)            Fang
Dai, GM, Global R&D (USA)

Lithium-ion batteries have been widely used
as one of the most important energy storage techniques in the past decades.
However, the energy density of current Li-ion batteries is insufficient to
satisfy the requirements for emerging technologies, such as electric vehicles
and smart grid, which is mainly limited by the low capacity of cathode
materials. Therefore, developing high-capacity cathode materials are urgently
needed. Although sulfur could offer high theoretical lithium storage capacity
when applied as cathode, the Li-Sulfur batteries significantly suffer from poor
cycling stability due to the insulating nature of sulfur and shuttling effect
of polysulfides. Most recently, selenium from same group as sulfur has been
considered to be a promising alternative for high energy and long cycle life Li
batteries due to its comparable volumetric capacity to but much better
electrical conductivity than sulfur.  However, Li-Se system also faces two
similar issues: shuttling of polyselenides and volume change during
charge/discharge processes.

    In this
work, we strategically design and fabricate a self-supported selenium composite
with a 3D hierarchical architecture constructed by mesoporous carbon and
graphene, in which selenium is impregnated into the mesoporous carbon
nanoparticles (Se/MCN), followed by further embedding between graphene sheets
(Se/MCN-RGO). Structural characterization by
XRD and SEM/TEM provide clear evidence for the unique structure. Such architecture not only provides the electrode with excellent
electrical and ionic conductivity, but also efficiently suppresses
polyselenides shuttling and accommodates volume change during charge-discharge
cycling. At selenium content of 62%, the Se/MCN-RGO cathode exhibits not only high
discharge capacity of 655 mAh g-1 at 0.1 C (97% of theoretical capacity) but
also long cycling stability under high rate (a very small capacity decay of
0.008% per cycle over 1300 cycles at 1C). It is furthermore believed that the
concept of such 3D hierarchical carbon architecture could be easily expanded to
other advanced energy storage systems, such as silicon for Li-ion batteries and
metal oxide for supercapacitors. The structural and electrochemical
characterization results of the high-performance Se/MCN-RGO composite will be
presented.

Keywords: Long-life Li-Se
batteries; selenium cathode; mesoporous carbon; graphene