Download A Review of Cathode and Anode Materials for Lithium

A Review of Cathode and Anode Materials for
Lithium-Ion Batteries
Yemeserach Mekonnen
Aditya Sundararajan
Arif I. Sarwat
IEEE Student Member
Department of Electrical &
Computer Engineering
Florida International University
Email: [email protected]
IEEE Student Member
Department of Electrical &
Computer Engineering
Florida International University
Email: [email protected]
IEEE Member
Department of Electrical &
Computer Engineering
Florida International University
Email: [email protected]
Abstract—Lithium ion batteries are one of the most
commercially sought after energy storages today. Their
application widely spans from Electric Vehicle (EV) to portable
devices. Their lightness and high energy density makes them
commercially viable. More research is being conducted to better
select the materials for the anode and cathode parts of Lithium
(Li) ion cell. This paper presents a comprehensive review of the
existing and potential developments in the materials used for the
making of the best cathodes, anodes and electrolytes for the Liion batteries such that maximum efficiency can be tapped.
Observed challenges in selecting the right set of materials is also
described in detail. This paper also provides a brief history of
battery technology and their wide applicability in the energy
market today, the chemistry and principle of operation behind
the batteries, and their potential applications even beyond the
energy sector. Safety concerns related to Li-ion batteries have
also been taken into account considering recent events.
technologies such as plug-in HEVs. For greater application use,
batteries are usually expensive and heavy. Li-ion and Li- based
batteries show promising advantages in creating smaller,
lighter and cheaper battery storage for such high-end
applications [18]. As a result, these batteries are widely used in
common consumer electronics and account for higher sale
worldwide [2]. Lithium, as the most electropositive element
and the lightest metal, is a unique element for the design of
higher density energy storage systems. The discovery of
different inorganic compounds that react with alkali metals in a
reversible way has opened doors to the design of rechargeable
Li-ion batteries [15]. This phenomenon, as defined later, is
called intercalation, which is the reversible inclusion of
molecules between two other molecules [2].
Index Terms—Cathode, Anode, Graphite, Lithium ion,
Battery, Safety
I. INTRODUCTION
Lithium-ion batteries are used in different technologies
such as the Hybrid Electric Vehicles (HEV), which use both
battery as well as electric motor engines to increase the fuel
efficiency [1]. A battery is essentially many electrochemical
cells connected in series or parallel to provide voltage and
capacity. Each cell contains a positive (cathode) and negative
(anode) electrode divided by an electrolytic solution, simply
called as an electrolyte, with dissociated salt that allows ion
transfer between electrodes [2]. When these electrodes are
connected to an external source, electrons are released as a
result of chemical reaction and therefore for current to be
tapped [25]. The electrical energy that a battery is able to give
is a function of both the cell and its capacity which are
dependent on the chemistry of the battery. For the purpose of
application, Nickel Metal Hydride (Ni-MH) is the common
battery technology currently being used [1]. However, different
research efforts have proven that Lithium ion (Li-ion)
chemistry has twice the power efficiency and density of NiMH. Out of the common batteries used in various applications,
lead acid, Nickel Cadmium (Ni-Cd), Nickel Metal Hydroxide
(Ni-MH), and Li-ion batteries have higher energy density, as
shown in Fig.1. These advances are reshaping the current
Figure 1 Energy density of different batteries [1]
II. CHEMISTRY
The materials involved in Li-ion batteries consist of carbon
which is porous in nature, usually graphite, as the anode, and
metal oxide for the cathode [15][24]. Like most battery
technologies, the working principle of Li-ion batteries involves
Lithium stored in the anode terminal that is transported to the
cathode terminal by an electrolyte [2]. Some of the most
common cathode components are Lithium Nickel, Manganese
This material is based on work supported by the National Science Foundation under Grant No. 1541108. Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
978-1-5090-2246-5/16/$31.00 ©2016 IEEE
Cobalt Oxide, Nickel Oxide, Cobalt Oxide, Manganese spinel,
Iron Phosphate, and Titanate. Among them, Lithium Nickel
and Manganese Cobalt Oxide have a higher energy density and
cell voltage. The electrolytic solution is lithium salt in organic
carbonate solvent containing “lithiated” ions [25]. The
operating principle behind Li-ion batteries is a recurring
transmission of lithium ions between the anode and the cathode
[11][12]. During the discharge process, solid state Li disperses
to the surface of the anode material to undergo an
electrochemical reaction which enables it to transfer Li+ ion
into the electrolytic solution [1]. The equilibrium equation for
such a reaction with graphite as the cathode material is as
follows:
The Li+ ion in turn passes through the electrolytic state
through dispersion and ionic conduction to react with the anode
and change back to its solid state. The equilibrium reaction at
cathode in this case with lithium metal oxide is presented as
follows:
Lithium will be stored inside the cell until the battery is
later recharged. At times of high current discharge, there is a
possibility that the cell can suddenly lose power depending on
the Li concentration, if saturated or depleted at the electrolyte
surface.
Fig.2 Schematics showing the working principles of a) Rechargeable Li-metal
battery, b) rechargeable Li-ion battery [1]
There are different types Li-ion cell geometries according
to the current manufacturing practices, namely the prismatic,
cylindrical, coin, and the pouch cell geometry which is the
most recent method. Both the cylindrical and prismatic cells
are commonly made of “laser-welded” aluminum can and
consist of liquid electrolyte. The pouch cell with aluminized
plastic bag contains Li-ion polymer electrolyte or gel. Bellcore
researchers were the first to advance their research on the
polymeric electrolyte called “plastic Li-ion (PLiON)” [2]. This
thin film battery technology gives the advantage of lightness,
flexibility and shape versatility when compared to the
cylindrical, prismatic or coin cell geometries.
Fig. 3 Different types of cell geometry a) cylindrical b) coin c) prismatic d)
pouch [4]
III. APPLICATIONS AND MARKET
Having a higher energy density when compared to other
battery technologies, rechargeable Li-ion batteries are and will
continue to control the market. By 2011, the rechargeable Liion battery market reached an approximate $11 billion and has
continued to grow [5]. These rechargeable batteries are utilized
in market segments where high energy and power density
applications are favored. The future of smart grid will heavily
consist of the Plug-in Electric Vehicles (PIEVs) as part of the
smart home power systems [20] [28] [29]. The EV and the
Plug-in Hybrid EVs (PHEVs) are perfect examples of such
applications [20] [21]. After many significant research efforts,
it is now plausible for consumers to use EVs such as Tesla
model S, or PHEVs like Chevrolet Volt, all powered by Li-ion
batteries [22].
The challenges for these market segments are the
manufacturing cost, higher price of Li-ion batteries and safety
concerns. A few of the other Li-ion applications are
commercial portable technologies such as cellphones, laptops
and tablets, aeronautics, and industrial energy power stations
[23]. There are numerous advantages to Li-ion batteries. They
are light weight which makes them the perfect candidates for
the recently sought-after portable technologies. They have a
high open circuit voltage and high energy density. They are
characterized by lack of memory, small self-discharge rate, and
less environmental impact when disposed. They, however,
have their own challenges where recent cases of unprovoked
inflammation have raised a constant safety concern [26].
The use of Li-ion batteries for the aforementioned
applications faces challenges. For one, the battery performance
has to be in tune with the applications it is used for. Safety, as
mentioned, remains a concern. The battery performance,
usually measured in capacity, energy density, and cell
potential, is directly related to the properties of the materials
which form the positive and negative electrodes [13]. Safety
concerns can be addressed through extensive studies of battery
chemistry, and cell engineering [17]. Present research is being
conducted in finding new materials which can act as anode and
cathode, to offer better performance arrangements of electrodeelectrolyte-electrode [2]. In addition, finding the right
electrolyte combination to avoid damaging reactions associated
with “electrode-electrolyte interface” is another challenge that
is currently being researched about [19].
IV. ANODE MATERIALS
Currently, the two most commonly used anode materials
are those based on carbon (graphite) and lithium alloyed
metals. One of the commercialized lithium alloyed metal is the
oxide spinel Li4Ti5O12 the structure of which is shown in Fig.4.
acceptance of Li, flexibility to temperature control as result of
its organic structure, and optimal cycling ability [4]. Through
structural and surface modifications, carbonaceous anodes have
shown consistent improvements in their charge-discharge
efficiency and discharge capacity. There have been new
developments where artificial graphite has been designed by
Hitachi by altering pore and particle structures [4].
Fig.5. Structures of common electrode material [4]
Fig.4. The basic chemical structure of Li-ion batteries [17]
To avoid issues in the cycling and safety which are
associated with dendrite formation on lithium anodes, it is
advisable to use the minimal potential intercalation electrode
[5]. The element found in the graphite intercalation alloy
protects the inserted lithium, making it less reactive towards
electrolytes. This will make the amount of Lithium in the
lithiated material less, which comes with both advantage and
disadvantage. The advantage is that it accounts for any safety
concerns regarding the flammability of the electrochemical
reactions. The disadvantage is manifested in the form of loss in
performance owing to a reduction in the cell voltage, [4] which
further reduces the energy density and power.
A. Carbonaceous (carbon-based) anodes
As discussed earlier in this paper, one of the primary
carbon materials used as anode is graphite. They consist of
sheets packed in hexagonal (AB) or rhombohedral (ABC) [5]
arrangements as referenced in Fig.4. When lithium ion is
inserted, these graphene sheets rearrange themselves on top of
each other in AA arrangement and “staging” occurs. Its
minimal cost, accessibility and favorable electrochemical
properties form the pros; carbon is the key anode material in
Li-ion batteries. However, compared to Li-ion alloys, graphite
carbon has poor lithium intercalation capacity. Graphitic
carbons are used an anode material in the frontier of
commercial Li-ion cells, mainly portable devices. Crystalline
carbon has also been claiming prominence due to its higher
B. Novel graphite and non-graphitic anodes
A lot of advances are being made using altered natural
graphite and other graphitic carbons such as “kish” graphite
[4]. Recent studies have shown that the electrochemical
characteristics are better improved on modified graphite as a
result of the oxidation of natural graphite in air. Aritifcal
development to graphitic anodes requires heat treatment at
temperatures starting 3000 C, which requires higher energy
and might lead to the production of gaseous materials. Kish
graphite shows Li intercalation capacities well above the set
theoretical value equal to 372mAh/g [7]. In addition, the
production of Kish graphite is cheap and can be done at a
lower temperature of 1500 C.
Non-graphitic carbons are those having graphene domains but
do not possess the structural order exhibited by graphene.
They are also known as disordered carbons. Although their
irreversible capacity does not compare with natural grapheme,
these materials are less vulnerable in solid electrolyte interface
disruption [5]. This makes them the perfect materials to be
paired with Li-Manganese Oxide where the dissolution of
metal is challenging.
C. Lithium alloy anodes
Among the top studied Li-alloy anodes, Li-Al (lithium
aluminum) is the first to be developed as the anode for Li-ion
batteries. Challenges related to cycling can be improved by
introducing substances such as Di-Lithium Phthalocyanine
which changes the anode surface film. One other challenge for
this material is the volumetric change during lithiation and
dilithiation processes. However, this problem can be solved by
the use of “dimensionally stable” anodes. This can be done by
the utilizing a submicron particle alloy which is surrounded by
a stabilizing matrix and “intermetallic” host where one metal
alloys with Li but the others do not [4]. Group of metals that
alloy with Li are Al, Bi, Cd, Mg, Sn, and Sb, whereas those
that do not are Co, Cu, Fe, and Ni. Some of these intermetallic
elements that have shown promising result as anode materials
are Al3Ni, Fe-Sn, Sn-Sb and Sn-Cu [8].
Lithium titanium oxide is another material that has been
branded as an alternative to carbon anodes. This material cycle
well since it does not exhibit any volumetric changes during Li
insertion and extraction process unlike most other intercalation
electrodes [6]. Its usage is limited to applications that do not
require a high energy density as a result of its high operating
voltage. Due to its low conductivity, this material is
recommended to be nanostructured.
V. CATHODE MATERIALS
The cathode material in Li-ion battery chemistry is the
major and active source of all the Li-ions [17]. The preference
of positive electrode materials depends on rechargeable Limetal or Li-ion batteries. The Li-metal, when used in
rechargeable Li batteries, the metal acts as a negative electrode,
therefore the positive electrode does not need to be lithiated. In
the case of Li-ion, because carbon electrode which acting as
the negative doesn’t have Li, the positive terminal must act as
source of Li; therefore intercalation compound is required for
the cell assembly [6]. The most common cathode materials are
LiCoO2, Li-Mn-O, LiFePO4 and lithium layered metal oxides
[5][17].
A. Lithium Manganese spinels (Li-Mn-O)
Li-Mn-O is one of the oldest compounds researched that
dates back to centuries ago; it is still widely used. Its first use
was depolarizer. It is easily accessible, has low cost and
possesses desirable electrochemical properties. When
compared to the high cost and toxic lithium cobalt based (LiCo-O), and difficult to produce lithium-nickel based (Li-Ni-O),
lithium manganese (Li-Mn) is the most widely used battery
material. Its different forms make it ideal for the intercalation
of small helium and lithium ions. The lambda form with its
spinel (Mn2O4) allows for the intercalation of Li-ion [6]. Some
of the advantages of Li-Mn spinels are high thermal threshold,
great rate capability, and minimal health and environmental
impacts. The diffusion rate for Li+ ion in this compound is 10-6
-10-10 sq. cm/s [5]. Challenges arise in reduced capacity upon
frequent cycling. This is due to the instability of the
electrochemically active Mn3+ ion above 55o C temperatures.
For such cases, improvements can be made by doping selected
metal ions (Al, Co, Cr, Fe, Mg, Ni, Mg, etc.) and coating acid
resistant materials on LiMn2O4 to obtain different structural
stability.
Fig. 6 Cubic spinel LiMn2O4 structures [9]
B. Lithium metal oxides
Lithiated nickel and cobalt oxides are the most in-depth
studied cathode material for Li-ion batteries. Both are
characterized by high structural stability. Limited resources can
be a challenge for manufacturing making them costly and hard
to synthesis. A resolution for this has been in the development
of solid solutions of these layered compounds. Li Ni0.5Mn0.5O2
and Li1.2Cr0.4Mn0.4O2 are the most common solid solution
compounds [6]. A research performed shows that a combination
of low-valent transition metal ions and low strain in the
activated state is key to high rate capability cathodes [8].
Layered metal oxides are perfect for applications requiring fast
charging and discharging. These materials appear to be doing
well on capacity when subjected to temperatures above 300oC.
Fig.7 Layered lithium metal oxides structure [16]
C. Olivines
They are known by their compound name LiFePO4. They
possess flat discharge plateau and moderate capacity ranging
from 150-160 mAh/g [6]. They are non-toxic and show little
capacity decline through the life of a battery. These compounds
are characterized by smaller volume charges and charge and
discharge heat flow when compared with other cathode
materials. They offer significant safety advantage over Licobalt based cathode, which makes them favorable for higher
level applications [23]. The transition metal iron (Fe) is cheap,
readily available, and environmentally gentle. However,
conductivity for these materials are poor and charging voltage
drops below 4V [4]. Two methods have been proposed to
improve this challenge. One involves the reduction of cathode
particle and the second is to use nanocomposite of LiFePO4
with conductive carbon matrix [4][30]. This has opened doors
to the advances in synthesizing olivines with other transition
metals. Although, it can be difficult to synthesize olivines with
transition metals and can experience limited capacity, they
exhibit high discharge potential and high energy out [6].
Fig.8 Olivines structure [14]
VI. ELECTROLYTES
For a rechargeable Li-ion battery, there are two types of
electrolyte technologies: polymer base and liquid electrolyte
[18]. A sustainable battery technology relies on good
electrolyte comprising the salt and solvent combination.
Polymer-based electrolytes add further selection criteria linked
to the electrochemical stability of polymer. These become a
challenge since there are only a few Li-based salts or polymers
to achieve high ion conduction, Polyethylene Oxide (PEO)
being the common one. For liquid electrolytes, there are
different solvents with specific dielectric and viscosity
constants that can be selected to achieve higher ionic
conduction. However, there are challenges in both
technologies. In liquid electrolyte, the ion conduction of the
electrolyte is “field-trial” process, guided by the concepts of
dielectric and viscosity constants [3]. In case of the polymer
electrolyte, achieving high ionic conduction in Li-based
polymer entails an in-depth understanding of ionic dissociation
and transport.
VII. SAFETY
Lithium-ion battery hazards, as any other battery
technology, are associated with electrical and chemical risks.
The different risks associated with Li-ion batteries are chemical
and electrical hazards, cumulative effects (both chemical and
electrical) and high voltage hazard, and hazards due to the loss
of a function of the battery. Chemical hazards stem from any
chemicals used in the battery [8]. The hazard could be as a
result of spillage or flammable tendencies of substances.
Electrical hazard of Li-ion batteries is associated with electrical
energy content based on the state of charge. During high
discharge and charge processes, the heat dissipated by electric
current should be properly thermally managed. Unwanted
exothermic reactions are prone to occur as a result of the
overcharge and discharge of the battery [10]. When batteries
are subjected cyclical discharge and charge, the increase in
battery temperature is accelerated, creating a chemical
instability of the battery materials. For such a hazard, it is
generally recommended to have electronic protection based on
the voltage thresholds [2]. In the past, Li-ion batteries used for
large industrial application for over 60V have presented
considerable occupational health damage. As a result, all Li-ion
batteries used for high voltage application (over 60 V) must
follow the recommended protection standards such as terminals
and insulation fault controls, to avoid hazardous exposure to
the battery [3].
There exist many safeguard tests as tabulated in [26], which
are predominantly applied for EVs and are designed to mitigate
or even prevent failures. However, thermal stability of active
materials within the battery at high temperatures has been a
constant concern. Thermal runaways triggered by internal
short-circuiting of the batteries are a huge threat. Runaway
temperature for Li-ion batteries is typically between 130C and
well over 200C. Cathode materials which release oxygen at
high temperatures have known to possess high reaction rates as
well as enthalpies, which favors inflammation, short-circuiting
and unprovoked combustion of the battery. A comprehensive
risk assessment to appraise and evaluate the different failure
modes through fault tree analysis must be conducted during the
manufacturing process itself.
Another ensemble of safety evaluation techniques are
provided in [27]. Cyclic Voltammetry is used to evaluate the
electrochemical stability of the battery constituents.
Differential Scanning Calorimetry (DSC) is an analytic
technique that assesses the implications of thermal abuse on
batteries by measuring the thermal response of selective
combinations of cell components over a wide range of
temperatures, maintaining the scanning at a fixed temperature
rate. The thermal stability of cells can be further quantified and
analyzed using Thermal Ramp Testing, where the battery is
heated in a linearly programmed fashion until it fails. These
and many other tests help us understanding the significance of
adherence to safety regulations and standards prescribed for Liion batteries.
VIII. CONCLUSION
This paper conducted a comprehensive review on the
evolution of battery technology, the various cathode and anode
materials widely employed, and their pros and cons associated
with the corresponding applications they are deployed in. The
electrochemical reactions behind the battery technologies were
also elaborated, backed by safety concerns with regard to the
batteries today, were also described and elaborated. There is a
huge demand for lighter, space efficient, and high capacity
batteries. This demand will continue to steadily increase with
technology maturation. Li-ion batteries are most highly
researched and the future energy storage for higher application
especially in EVs and PHEVs. Through extensive material
research and design, there should be an improvement in the
energy density for Li-ion batteries. Future developments in the
Nano approach such as the carbon nanotube anodes, silicon
anodes and nanoparticles that can be used as cathode are
promising advancements to the future of Li-ion based batteries.
REFERENCES
[1] Smith, K. A, “Electrochemical Control of Lithium–Ion
Batteries,” Control Systems, IEEE 30, no.2 (2010), pp. 18-25,
[2] Tarascon, J-M., and Michel Armand. "Issues and challenges
facing rechargeable lithium batteries." Nature 414, no. 6861
(2001): 359-367.
[3] RECHARGE aisbl. “Saftey of Lithium-ion Batteries” The
European Association for Advanced Rechargeable Batteries.
(2013)
[4] Shukla, A. K, and Prem Kumar, T. “Materials for Next
Generation Lithium Batteries.,” Current Science Vol. 94 No. 3
(2008) pp 317-327
[5] Kam, K. C. and Doeff, M. M. “Electrode Materials for Lithium
Ion” Material Matters, Vol. 7, No. 4, (2012)
[6] Electronic Properties of Materials, 4th ed. Springer, NY, 2011,
pp 110-111
[7] Stoeva, Z., Jager, B and et al “Crystal Chemistry and Electronic
Structure of the Metallic Lithium Ion Conductor, LiNiN” JACS
Vol. 129 No. 7 (2007)
[8] Leung, K “Electronic Structure Modeling of Electrochemical
Reactions at Electrode/Electrolyte Interfaces in Lithium Ion
Batteries” Sandia National Lab. , (2013)
[9] Inoue, N, and Zou, Y. “Electronic Structure and Lithium Ion
Migration of La 4/3-yLi3yTi2O6 using Cluster Model” Solid
State Ionics 176 (2005)
[10] C. Mikolajczak, M. Kahan, K. White, R. T. Long “Lithium-ion
Batteries Hazard and Use Assessment: Final Report” The fire
protection research foundation, July 2011
[11] J. Vetter, P. Novak, M.R. Wagner, C. Veit, K.C.Moller,
J.O.Besenhard, M.Winter etc “Aging Mechanisms in Lithiumion Batteries” Journal of Power Sources 147 (2005)
[12] M.
Wohlfahrt-Mehrens,
C.Vogler,
J.Garche
“Aging
Mechanisms of Lithium Cathode Materials” Journal of Power
Sources 127 (2004)
[13] P. Rong, and M. Pedram “An Analytical Model for Predicting
the Remaining Battery Capacity of Lithium-Ion Batteries”,
IEEE Transactions on VLSI Systems, Vol.14, No.5, May 2006
[14] M.Stanely Whittingham “Lithium Batteries and Cathode
Materials” Chemical Reviews 2004, Vol.104, No.10
[15] J.W.Fergus “Recent Developments in Cathode Materials for
Lithium-ion Batteries: Review” Journal of Power Sources 195
(2010) 939-954
[16] B. Dunn, H. Kamath, J, Tarascon “Electrical Energy Storage for
the Grid: A Battery of Choices: Review” Science Magazine
2011, Vol. 334, PP 928-935
[17] X. Chen, W. Shen,T. Vo, Z.Cao and A. Kapoor “ An Overview
of Lithium-ion Batteries for Electric Vehicles” IPEC, 2012
Conference on Power and Energy.
[18] O. Gross, J. Swoyer “The Next Step in Low Cost Lithium-Ion
Polymer Systems” IEEE Battery Conference on Applications
and Advances 2002
[19] M. H. Miles “Recent Advances in Lithium Battery Technology”
2001 IEEE GaAs Digest
[20] M.H. Amini, A.I. Sarwat, "Optimal Reliability-based Placement
of Plug-In Electric Vehicles in Smart Distribution Network’,
International Journal of Energy Science, April 2014, 4(2), 43-49
[21] Gholami, J. Ansari, M. Jamei, A.I. Sarwat, “Combined
Economic and Emission Dispatch Incorporating Renewable
Energy Sources and Plug-In Hybrid Electric Vehicles”,
International Journal of Energy Science, April 2014, 4(2), 60-67
[22] M.H. Amini, and A.I. Sarwat, “Allocation of Electric Vehicles'
Parking Lots in Distribution Network", M.H. Amini, and A.I.
Sarwat, IEEE PES 5th Innovative Smart Grid Technologies
Conference (ISGT 2014), Washington, DC, Feb 19-22, 2014.
[23] M. Islam, A. Omole, N. Damnjanovic, A.I. Sarwat, Jr. A.
Domijan, “Dynamic Capacity Estimation for a Typical GridTied Event Programmable Li-FePO4 Battery”, IEEE
International Energy Conference Bahrain, December 2010
[24] Research and Market Report “Lithium Ion phosphate: A
promising cathode Active Material for Lithium Secondary
Batteries” Trans Tech Publications Inc. Chap 5, 7, &8 April
2008
[25] M. Winter, R. J. Brodd “What are Batteries, Fuel Cells &
Supercapacitors?”, Chemical Reviews, Published by American
Chemical Society, February 2005
[26] U.L. Newscience technical report, “Safety Issues for Lithiumion Batteries”, October 2009
[27] D. Doughty, E.P. Roth, “A Generic Discussion of Li-Ion Battery
Safety”, The Electrochemical Society Interface, May 2012
[28] A.H. Moghadasi, A. Sundararajan, A.I. Sarwat, “Power
Management and Control Strategy in Standalone DC Microgrid
along with SMES Solenoid Coil”, International Journal of
Enhanced Research in Science Technology & Engineering, Vol.
3 Issue 10, October-2014, pp: (102-112)
[29] A.I. Sarwat, Jr. A. Domijan, A. Damnjanovic, “Assessment of
the reliability of a Dynamic Smart Grid System”, International
Journal of Power & Energy Systems, July 2011
[30] W.He, Q.Chen, T.Zhang,Y.Gao, J.Cao, “Solvothermal
Syntehesis of Uniform Li3V2(PO4)3/C Nanoparticles as Cathode
Materials for Lithium Ion Batteries,” in Micro & Nano Letters,
IET, vol10, no.2, pp 67-70, 2 2015