History of lithium-ion battery
The 2019 Nobel Prize for chemistry honours three men who contributed to the development of this ubiquitous power storage device
The lithium–ion (LI) battery is now such an integral part of modern life, we don’t think about its history. Every mobile phone and laptop is powered by LI batteries. They are also used to power electric vehicles and store renewable power.
The 2019 Nobel Prize for chemistry honours three men who contributed to the development of this ubiquitous power storage device. They are Stanley Whittingham, (State University of New York, Binghamton), John Goodenough (University of Texas, Austin), and Akira Yoshino (Asahi Kasei Corporation, Tokyo).
Most people saw the Nobel announcement on some device powered by their “baby”. LI batteries are lighter and more compact than previous batteries. Packs can be scaled up, to handle large power demands, and also scaled down, for micro-currents.
Batteries became common enough by the late 19th century when electric torches became common. The automobile industry (and ships) use batteries as well. The theory of circuitry was understood by mid-19th century.
Any circuit has two electrodes, a cathode and an anode. Electrons (negatively charged ions) and positively charged ions flow in opposite directions, with electrons going from anode to cathode, while positive ions move vice-versa. That sets up the current. Recharging involves reversing the current direction, storing electrons again. The electrodes are connected through a medium called an electrolyte (liquid or solid) to complete the circuit.
Early batteries used lead-acid combinations and were heavy and inefficient. Modern battery research was triggered by weapons developments in the Cold War, and by the Space Race. By the 1970s, fears of fossil fuel supply disruptions caused by the 1973 Yom Kippur War and the 1979 Iran Revolution, triggered interest in renewables. Environmental concerns also started to play their part.
One issue with earlier rechargeable batteries is that the electrodes are worn down, and every recharge causes deterioration. Lithium is the lightest metal and yields ions easily, meaning less deterioration. But lithium is very chemically active. It’s never found in a free state since it explosively reacts with oxygen in the air at room temperatures. This is why there are issues with LI batteries occasionally exploding.
Whittingham (born 1941) researched superconductors. In the 1970s, he laid the basis for the material sciences that led to the discovery of materials now used in LI cathodes. The first material was titanium disulphide, a chemical with a crystalline structure containing lithium ions in spaces at molecular levels — this is intercalation. The anode was a lithium mix, which easily releases electrons. This battery was too explosive to be commercially viable though it delivered higher voltages than anything before it. His lab in Exxon suffered a succession of fires caused by failed experiments.
Goodenough (born 1922 and the oldest recipient of the Chemistry Nobel) is unusual even by the standards of Nobel winners. He was born dyslexic in an era when educational methods for people with reading difficulties didn’t exist. He also made contributions to the development of Random Access Memory for computers. He still goes into the lab every day.
Goodenough found cathodes made out of metal oxides, instead of metal sulphides, had higher potential (pun intended). In 1980, he showed cobalt oxide with intercalated lithium ions is higher voltage and long-life.
Using Goodenough cathodes, Yoshino (born 1948) created the first commercially viable LI battery in 1985. He swapped out reactive lithium in the anode with petroleum coke, a carbonbased material that also intercalates LI. One big advantage is that the intercalation happens at the electrodes and the ion move through the electrolyte without reactions. The Yoshino battery never uses metallic lithium, which makes them safer.
By 1991, commercial LI batteries were widely available. A modern LI battery stores about 150 watt-hours of electricity per kilogram. NIMH (nickel-metal hydride) batteries store a maximum of 100 watt-hours per Kg. Older lead-acid batteries store only 25 watthours/kg. LI holds charges much longer and they don’t have “memory effects”, which means complete discharge isn’t required before recharge. However, LI batteries also deteriorate fast even if they aren’t being used and they are heat-sensitive. And once in a while, they do explode.
They’re also more expensive partly because battery packs can’t be managed without smart chips to control power flows. The battery in a laptop for instance, is actually a pack of several batteries. It is controlled by an onboard chip that tracks temperature via sensors, and controls voltage and charge/recharge functions.
Nobels are handed out for all sorts of research, often after some practical application or another, has been discovered. But few Nobels will have this sort of instant resonance for everybody.