(306a) Novel Centrifugation-Assisted Preparation (CAP) of Additive-Free Carbon-Decorated Fe3O4 Electrodes with Superior Electrochemical Performances for Lithium-Ion Batteries

2015
AIChE Conference

Novel Centrifugation-Assisted Preparation (CAP) of Additive-Free
Carbon-Decorated Fe₃O₄ Electrodes with Superior
Electrochemical Performances for Lithium-ion Batteries

Jian Zhu
(speaker); K. Y. Simon Ng; Da Deng*

Department of Chemical Engineering and
Materials Science, Wayne State University,

5050 Anthony Wayne Dr, Detroit, MI,
United States, 48202

Email: da.deng@wayne.edu

Abstract

Lithium ion batteries (LIBs) are the dominant power
sources for portable electronic devices, and are penetrating into the market of
electric vehicles and sustainable energy grid. There is an increasing demand
for higher energy and high powder LIBs. The electrochemical performances of
LIBs are mainly determined by the electrodes selected. Taking anode for
example, the theoretical capacity of commercial anode of graphite is only 372
mA h/g, and its performance is about to saturate after few decades of
development. To further increase the energy density, carbon must be replaced by
environmentally friendly and inexpensive materials with high capacity and
excellent reversibility. On the other hand, the current conventional procedure
in the preparation of electrodes is time consuming involving multiple steps,
including materials preparation, slurry formation, coating on to current
collectors, and drying in vacuum. Various additives, including binder polyvinylidene
fluoride (PVDF), conductive enhancer carbon black (CB), and organic solvent N-Methyl-2-pyrrolidone
(NMP), are required in electrode preparation. The complicated procedure and
various additives lead to the high cost of electrodes. It would be beneficial
but is still challenging to develop facile methods for electrode preparation
with simplified procedure, without using any additives, but with superior
electrochemical performances.

Herein, we demonstrated a novel and facile centrifugation-assisted
preparation (CAP) of additive-free negative electrode of carbon-decorated Fe₃O₄
materials for high energy LIBs (Figure 1a). Notably, the materials were
directly synthesized on the current collectors. No additives, such as PVDF
binder, carbon black conductivity enhancer and NMP solvent which are typically used
in conventional electrodes, were required. Interestingly, the as-prepared of carbon-decorated
Fe₃O₄ negative electrodes exhibited superior electrochemical
performance with stable specific capacity of 800 mAh/g (more than two times of
theoretical capacity of graphite at 372 mAh/g) for at least 240 cycles at
100mA/g; (Figure 1b) no significant capacity decay was observed when the
testing currents were increased, up to 1500 mA/g, demonstrating excellent rate
performances for high power LIBs (Figure 1c). We believe that our facile CAP
method could be used for the preparation of electrodes, including cathodes and anodes
with or without additives, based on other active materials.

Figure
1.
(a) Schematic of three steps of CAP of additive-free electrodes with
carbon-decorated Fe₃O₄ on Cu current collector and
corresponding optical images on the bottom; (b) excellent cycling performance tested
at current of 100 mA/g for 240 cycles; and (c) rate performances and Coulombic
efficiency at different currents from 100 to 1500 mA/g of the CAP electrodes of
carbon-decorated Fe₃O₄ without any additives.