IEEE Electrification Magazine - September 2015 - 16

60
55
50
45
40
35
30

(%)

(GW)

a compound based on manganese
dioxide (Thackeray et al., 1983). This
new compound had price advantages
over the cobalt compound; however, its
lower capacity and stability issues
allowed LiCoO2 to take over the market.
In 1997, Goodenough, at the Univer2012
2015
2020
2025
2030
2035
2040
sity of Texas, Austin, developed a new
Year
material for the cathode-LiFePO4. This
Wind
Solar
Percentage of All Other Renewables
material gave the cell better stability,
flattening the discharge characteristic
Figure 1. The forecast for solar and wind generation capacity in relation to all other renewables.
profile and bringing, among others, the
following advantages (Padhi et al., 1997):
batteries, which he called intercalation compounds. Exxon
xx
It has a high output performance with standard discommercialized this first rechargeable battery with a lithicharge for 2-5 C and continuous-discharge high-curum-aluminum anode, but its low-voltage profile (only
rent capacity of up to 10 C and the instantaneous disaround 2 V) made it insufficient for many applications
charge pulse up to 20 C.
xx
Good performance is observed at high temperatures from
(Pistoia, 2014).
65 to 95 °C, keeping the battery in good safe condition.
In 1980, at Oxford University, John Goodenough developed
xx
It shows excellent performance after 6,000 cycles, with
LiCoO2 as a cathode material. This new compound offered a
higher energy density to Li-ion cells (Wkihara and Yamamoa discharge capacity above 80% (Sony Corp.).
xx
It charges quickly, taking significantly less charging
to, 1998 and Mizushima et al., 1980). The applications and
time compared to other batteries.
market were not foreseen then, and it was not until 1991 that
xx
It is an environmentally friendly battery that does not
Sony, based on the developments made by Akira Yoshino,
produce any waste.
started the commercialization of the first rechargeable
In 2002, A123, a Massachusetts Institute of Technology
LiCoO2 battery (Yoshino, 1986). The cell was based on the discovery made by Goodenough but with the addition of a carstartup, was the first company in the world to commerbonized material in the anode. From that point, Li-ion battercialize LiFePO4. Sony has become one of the industry
leaders in the production of these types of batteries in
ies became the subject of investigations by several labs and
the last five years. Sony Fortelion initially had a 2,000universities aiming to discover the next revolutionizing
cycle life, and this was recently improved to 10,000
material that would allow a higher power density.
cycles, or ten years, with more than 98% discharge
In 1983, another cathode structure was developed at
capacity (Sony Corp.).
Oxford by Goodenough's research group. Michael Thackeray
Although the advances in new materials for anodes and
developed the structure, called the spinel, and used
cathodes continue in laboratories around the world, commercially speaking, LiCoO2 and LiFePO4 are the leading
technologies for electric vehicles and grid energy-storage
systems. The price is trending down, and it is only a matter
A
of time before LiCoO2 and LiFePO4 become the industry
Anode
Cathode
e
e
standard for energy storage, displacing the well-known
-
+
lead-acid and nickel-cadmium batteries.
Electrolyte
100
80
60
40
20
0

Market Aspects

Copper
Current
Collector
Li+ Solvent
Graphene
Molecule
Structure

Aluminum
Current
Collector

Figure 2. The discharging process of a Li-ion cell (Yoshio et al., 2009).

I E E E E l e c t r i f i cati o n M agaz ine / SEPTEMBER 2015

The price reduction of Li-ion compared to the traditional
lead-acid batteries will have a significant impact on the
future of the storage market. According to EuPD Research,
the price for Li-ion versus lead-acid was, in an average
for the different categories of storage size, only 1.8 times
higher in 2014, while the number of cycles was several
times larger-including Sony's Fortelion, with specifications of 100 times more cycles than the standard lead-
acid battery-producing a very favorable cost-to-cycle
ratio (EuPD, 2009). This means that very low-cost battery
storage solutions are already available. Figure 3 shows a
comparison of lead-acid and Li-ion in different capacity
categories for battery storage.

Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2015