Page 28 - EngineerIt July 2021

ELECTRONICS
South Africa has
played a major part
To demonstrate the differences, here is a Lithium titanate
brief summary. Virtually identical to manganese oxide, in lithium battery
lithium titanate was created in 2008 and is development
Lithium cobalt oxide one of the newest subsets of the Lithium-
Lithium cobalt oxide consists of a cobalt ion battery family. Lithium titanate replaces n 1974, at the time of the first ‘oil crisis’
oxide cathode and graphite anode in a the graphite anode in the typical lithium-ion when the price of oil jumped from
layered structure. Lithium cobalt oxide battery, forming a spinal structure allowing I$3 to $12 a barrel, Johan Coetzer, a
batteries have high specific energy of the cathode to be manganese oxide or structural chemist, returned from a year’s
150-200Wh/kg which is why they are nickel manganese cobalt. Lithium titanite farming to resume his scientific career
used in mobile phones, laptops and digital has an outstanding low-temperature at the Crystallography Division of the
cameras. However, lithium cobalt has a discharge characteristic as it can be National Physical Research Laboratory, at
somewhat short life span, low thermal fast-charged and can deliver a massive the CSIR. The crisis created a worldwide
stability and limited specific power. discharge current. Although lithium awareness of the need for alternative energy
titanate excels in safety, low-temperature sources and improved batteries for energy
Lithium manganese oxide performance and life span, it has low storage. This prompted Coetzer to initiate
Lithium manganese oxide has a three- specific energy (90-120Wh/kg) and an structural studies of battery materials. New
dimensional framework structure due to its extremely high cost. Common applications to the field of solid-state electrochemistry,
crystalline cathode. Its spinal framework for lithium titanate are electric power trains, Coetzer embarked on an investigation of
allows the battery to be optimised for UPS and solar powered street lighting. the structure-electrochemical properties of
optimum life span, specific power (load Lithium nickel manganese cobalt oxide, silver iodide-amine iodide solid electrolytes
capability) or specific energy (capacity). lithium titanate and lithium iron can be used that showed anomalously high Ag+-ion
Lithium manganese offers low resistance for EVs, however each have their specific conductivity at room temperature. This
and moderate specific energy of 100- advantages and disadvantages. Lithium project heralded the start of a 20-year period
150Wh/kg. Common applications for lithium titanate has great energy density and when the CSIR and South Africa would
manganese are power tools, medical lifespan, but it has the disadvantage of low make major contributions to advancing
devices and electric power trains. safety, high cost and is a new lithium-ion international battery science and technology.
chemistry which has not been tried and When Michael Thackeray joined Coetzer in
Lithium nickel manganese tested over time. Lithium iron phosphate 1975, he used the silver iodide project for
cobalt oxide on the other hand is an older lithium-ion his PhD thesis, while Coetzer turned his
Manganese oxide was created in 2008 chemistry, with updates happening all the attention to more practical technologies.
and is one of the newest subsets of the time. It has been tried and tested and has The introduction of the first commercial
lithium-ion battery family. Lithium nickel high safety, low cost and a long lifespan, lithium-ion batteries by Sony Corporation
manganese cobalt oxide usually has a but a moderately lower specific energy. triggered a series of visits in 1992 and 1993
cathode combination of one-third nickel, by Ora Safriel of Technifin and Thackeray to
one-third manganese, and one-third Lithium iron phosphate various battery companies in Japan, Europe
cobalt. Nickel has high specific energy Lithium iron phosphate has a high current and the United States in an attempt to gauge
but weak stability; manganese has the rating and long life cycle, is more tolerant interest in, and exploit, the CSIR’s lithium
spinal structure that allows it to achieve to full charge conditions and is less battery patent portfolio.
low internal resistance, however it has low stressed than other lithium-ion systems. These visits heralded the start of a
specific energy. Lithium nickel manganese It has a specific energy of 90/120 watt- successful licensing campaign, particularly
combines both metals hence, enhancing hours per kilogram, a nominal voltage of with the major Japanese lithium battery
each of their strengths and giving them a 3.20V/3.30Va, a charge rate of 1C and a manufacturers. The first license was granted
specific energy of 150-220Wh/kg. Lithium discharge rate of 1-2,5C. in 1995 and others followed, generating
nickel manganese cobalt oxide has Lithium iron phosphate batteries have significant royalty income for CSIR/
industrial uses and is also used in E-bikes, an outstanding safety and long lifespan Technifin over the next several years. In
medical devices and some famous EVs. but, lithium iron phosphate loses some 1992, after supporting lithium battery
distance in terms of specific energy per research for approximately 10 years, the
Lithium nickel cobalt kilogramme. However, this is not important CSIR management decided to terminate its
aluminium oxide in a stationary application where weight is investment in this field, supposedly because
Lithium nickel cobalt aluminium oxide offers not a factor. The lithium iron phosphate cell of the lack of a lithium battery industry in
a high specific energy of 200-260Wh/kg, is superior in terms of safety and price over South Africa. They were unaware of the full
quality specific power and a long lifespan. other lithium-ion battery chemistry, and significance of the research being undertaken
However, lithium nickel cobalt aluminium typically has a higher life expectancy. n on the CSIR campus and did not foresee
oxide batteries have a high cost and a low the impending impact of lithium battery
technology that was to follow during the
safety rating. Electric vehicle power trains Revov is a leader in 2 LiFe lithium iron
nd
often use lithium nickel cobalt aluminium storage batteries for UPS systems and consumer electronics boom in the 1990s.
oxide batteries because of their long life renewable energy sources in Africa, and uses Reference: Twenty golden years of battery R&D
span, high energy and power densities. lithium iron phosphate batteries, which are a at CSIR, 1974 -1994 by Michael Thackeray SA
Again, other applications include industrial specific subset of the larger family of batteries Journal of Chemistry, 2011
called lithium-ion.
uses and medical devices.

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