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allied
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Journal of Materials Science and Nanotechnology | Volume: 3
March 20-21, 2019 | London, UK
Materials Science and Materials Chemistry
2
nd
International Conference on
L
iCoO
2
is the major cathode material for Li-ion batteries
(LIBs) since 1992 because it excels in many electrochemical
properties. However, recent research efforts have been
devoted to the development of Li(NixMnyCoz)O
2
where x +
y + z = 1 (NMC) because of the high price of Co and the high
specific capacity from NMCs. In spite of their cost and capacity
advantages, NMCs exhibit significant capacity decay during
charge/discharge cycles. It is found that most of the capacity
decay mechanisms start at the particle surface. As a result,
proper coatings can improve the cycle stability of NMCs. With
this in mind, we have investigated a new wet-chemical method
to coat nano-LiCoO
2
(LCO) particles and micro-Li(Ni
0.5
Mn
0.3
Co
0.2
)
O
2
(NMC532) particles. In this newly-developed wet-chemical
method, Al(NO
3
)
3
is used as the Al source to form Al
2
O
3
and
LiAlO
2
, whereas LiNO
3
is used as a sacrificial agent to protect
LCO and NMC particles and at the same time to form LiAlO
2
by reacting with Al
2
O
3
. Addition of LiNO
3
into the Al(NO
3
)
3
coating solution suppresses the unwanted formation of Co
3
O
4
during the coating process and leads to a thin (5–10 nm) and
continuous LiAlO
2
/Al
2
O
3
coating. LiAlO
2
/Al
2
O
3
-coated nano-
LCO exhibits an unusually high initial specific capacity of 225
mA hg
-1
, while micro-LCO can only deliver a specific capacity of
145 mA hg
-1
. For NMC532, the initial specific capacity has been
increased from ~160 mA hg
-1
to above 200 mA hg
-1
. In addition,
the charge/discharge cycle stabilities of both LCO and NMC532
have been improved substaintially. Furthermore, the rate
capabilities of both LCO and NMC532 have been enhanced as
well. The unusually high specific capacity and superior capacity
retention for long cycle life at high rates for both LiAlO
2
/Al
2
O
3
-
coated LCO and NMC532 are attributed to the effectiveness
of LiAlO
2
/Al
2
O
3
coating in preventing capacity decay during
battery soaking as well as during cycling. The principle and
methodology of this newly-developed wet-chemical coating
method are applicable to other layered transition metal oxide
cathodes and can open up newopportunities to obtain superior
electrochemical properties from these advanced cathodes in
the near future.
Speaker Biography
Leon L Shaw is Rowe family endowed Chair Professor in sustainable energy and professor of
Materials Science and Engineering at Illinois Institute of Technology (IIT), Chicago, USA. His
main research interest is in nanomaterials synthesis and processing for energy storage and
structural applications. In the arena of energy storage, his research team has worked on
various anode and cathode materials for Li-ion batteries, Na-ion batteries, supercapacitors,
and hybrid redox flow batteries over the last decade. He has authored and co-authored
more than 290 archival refereed publications with 8,000 plus non-self citations (according
to Google Scholar). He is a Fellow of ASM International, a Fellow of the World Academy
of Materials and Manufacturing Engineering, Poland, and a member of the Connecticut
Academy of Science and Engineering.
e:
lshaw2@iit.eduLeon L Shaw
Maziar Ashuri
and
Qianran He
Illinois Institute of Technology, USA
Coating as a potent method to enhance the specific capacity, charge rate and cycle life
of cathodes for next-generation Li-ion batteries