This discovery led to the invention of the first voltaic cell, more commonly known as a battery. Volta discovered further that the voltage would increase when voltaic cells were stacked on top of each other. Figure 3 illustrates such a serial connection. In the same year, Volta released his discovery of a continuous source of electricity to the Royal Society. No longer were experiments limited to a brief display of sparks that lasted a fraction of a second.
A seemingly endless stream of electric current was now available. France was approaching the height of scientific advancements and new ideas were welcomed with open arms. By invitation, Volta addressed the Institute of France in a series of lectures at which Napoleon Bonaparte was present as a member see Figure 4. Napoleon helped with the experiments, drawing sparks from the battery, melting a steel wire, discharging an electric pistol and decomposing water into its elements.
He connected the battery to charcoal electrodes and produced the first electric light. Davy began to test the chemical effects of electricity in and soon found that by passing electrical current through some substances, decomposition occurred, a process later called electrolysis. The generated voltage was directly related to the reactivity of the electrolyte with the metal. Davy understood that the actions of electrolysis and the voltaic cell were the same.
In , Dr William Cruickshank designed the first electric battery capable of being mass produced. Cruickshank arranged square sheets of copper with equal sheet sizes of zinc. These sheets were placed into a long rectangular wooden box and soldered together.
Grooves in the box held the metal plates in position. The sealed box was then filled with an electrolyte of brine, or watered down acid, resembling the flooded battery that is still with us today see Figure 5. In John F. Until then, all batteries were primary, meaning that they could not be recharged. It was based on lead and acid, a system that is still used today.
In , Waldmar Jungner from Sweden invented the nickel-cadmium battery NiCd , which used nickel for the positive electrode and cadmium for the negative. Two years later, Thomas Edison produced an alternative design by replacing cadmium with iron.
High material costs compared to dry cells or lead acid systems limited the practical applications of the nickel-cadmium and nickel-iron batteries. It was not before Shlecht and Ackermann achieved major improvements by inventing the sintered pole plate in that NiCd gained new attention [sintering is the process of fusing nickel powder at a temperature well below its melting point using high pressures]. This resulted in higher load currents and improved longevity.
The breakthrough came in when Neumann succeeded in completely sealing the nickel-cadmium cell. In the s and s, the attention was on nickel-based chemistries.
The stacking of the cells in series increases the voltage, while their connection in parallel enhances the supply of current. This principle is used to add up to the required voltages and currents, all the way to the Megawatt sizes. There is now much anticipation that battery technology is about to take another leap with new models being developed with enough capacity to store the power generated with domestic solar or wind systems and then power a home at more convenient generally night time for a few days.
When a battery is discharged the chemical reaction produces some extra electrons as the reaction occurs. An example of a reaction that produces electrons is the oxidation of iron to produce rust. Iron reacts with oxygen and gives up electrons to the oxygen to produce iron oxide. The standard construction of a battery is to use two metals or compounds with different chemical potentials and separate them with a porous insulator.
The chemical potential is the energy stored in the atoms and bonds of the compounds, which is then imparted to the moving electrons, when these are allowed to move through the connected external device.
A conducting fluid such as salt and water is used to transfer soluble ions from one metal to the other during the reaction and is called the electrolyte. The metal or compound that loses the electrons during discharge is called the anode and the metal or compound that accepts the electrons is called the cathode. This flow of electrons from the anode to the cathode through the external connection is what we use to run our electronic devices. When the reaction that produces the flow of electrons cannot be reversed the battery is referred to as a primary battery.
When one of the reactants is consumed the battery is flat. The most common primary battery is the zinc-carbon battery. It was found that when the electrolyte is an alkali, the batteries lasted much longer. These are the alkali batteries we buy from the supermarket.
The challenge of disposing with such primary batteries was to find a way to reuse them, by recharging the batteries. This becomes more essential as the batteries become larger, and frequently replacing them is not commercially viable. One of the earliest rechargeable batteries, the nickel-cadmium battery NiCd , also uses an alkali as an electrolyte. In nickel-metal hydrogen batteries NiMH were developed, and had a longer life than NiCd batteries.
These types of batteries are very sensitive to overcharging and overheating during charge, therefore the charge rate is controlled below a maximum rate. Sophisticated controllers can speed up the charge, without taking less than a few hours. Portable applications — such as mobile phones and laptop computers — are constantly looking for maximum, most compact stored energy.
While this increases the risk of a violent discharge, it is manageable using current rate limiters in the mobile phone batteries because of the overall small format. But as larger applications of batteries are contemplated the safety in large format and large quantity of cells has become a more significant consideration. Lithium is one of the lightest elements in the periodic table and it has one of the largest electrochemical potentials, therefore this combination produces some of the highest possible voltages in the most compact and lightest volumes.
This is the basis for the lithium-ion battery. In this new battery, lithium is combined with a transition metal — such as cobalt, nickel, manganese or iron — and oxygen to form the cathode. During recharging when a voltage is applied, the positively charged lithium ion from the cathode migrates to the graphite anode and becomes lithium metal.
The movement of electrons in the circuit gives us a current that we can use. Depending on the transition metal used in the lithium-ion battery, the cell can have a higher capacity but can be more reactive and susceptible to a phenomenon known as thermal runaway. In the case of lithium cobalt oxide LiCoO 2 batteries made by Sony in the s, this led to many such batteries catching fire.
The possibility of making battery cathodes from nano-scale material and hence more reactive was out of the question. But in the s Goodenough again made a huge leap in battery technology by introducing a stable lithium-ion cathode based on lithium iron and phosphate. This cathode is thermally stable. It also means that nano-scale lithium iron phosphate LiFePO 4 or lithium ferrophosphate LFP materials can now be made safely into large format cells that can be rapidly charged and discharged.
Many new applications now exist for these new cells, from power tools to hybrid and electric vehicle. Perhaps the most important application will be the storage of domestic electric energy for households.
The leader in manufacturing this new battery format for vehicles is the Tesla electric vehicle company, which has plans for building "Giga-plants" for production of these batteries. The size of the lithium battery pack for the Tesla Model S is an impressive 85kWh.
This is also more than enough for domestic household needs, which is why there has been so much speculation as to what Tesla's founder Elon Musk is preparing to reveal this week. Goodenough directed two postdoctoral assistants to methodically work their way through structures containing a group of oxides.
He asked them to find out at what voltage lithium could be extracted from the oxides—he expected it to be much higher than the 2. Their answer was that about half of the lithium could be pulled from the cathode at 4 volts before it crumpled. That was plenty for a powerful, rechargeable battery. Of the oxides they tested, the postdocs found that cobalt was the best and most stable for the purpose.
It was the first lithium-ion cathode with the capacity, when installed in a battery, to power both compact and relatively large devices, a quality that would make it far superior to anything on the market. It would result in a battery with twice to three times the energy of any other rechargeable room-temperature battery, and thus could be made much smaller and deliver the same or better performance. The result was an overnight blockbuster. In addition to battery sales, Sony solved a problem with one of its leading electronic products—hand-held video cameras.
The previously available batteries were simply too bulky for hand-held video use, but lithium-ion allowed Sony to offer a new, sleek version of the cameras, and they, too, became huge sellers. The Sony breakthrough triggered a frenzy in labs around the world to find even better lithium-ion configurations that would pack more energy in a smaller and smaller space.
Yet despite his central role in the first commercial lithium-ion battery, Goodenough earned no royalties. In the end, Goodenough signed away the royalty rights to the Atomic Energy Research Establishment, a UK government lab just south of Oxford, reasoning that at least his invention might reach the market. He never fathomed the scale of the market to come. No one did. Since a lithium-ion battery was relatively light for the amount of charge it held, it also re-opened the possibility of building economic electric vehicles.
Charlatans and hucksters thrive in eras of invention, since no one can truly know what will become the next bonanza. Batteries have been unusually marked by exaggeration and outright fraud: Because people intuitively understand the importance of a better battery and think that therefore the world should have one, they are vulnerable to deception.
In , Thomas Edison, misled too many times in the midst of creating his electronic empire, sized up rechargeable batteries as a mere fable. He wrote:. The storage battery is, in my opinion, a catchpenny, a sensation, a mechanism for swindling the public by stock companies. The storage battery is one of those peculiar things which appeals to the imagination, and no more perfect thing could be desired by stock swindlers than that very selfsame thing.
Goodenough himself recalls the story of a Japanese materials scientist by the name of Shigeto Okada. Okada arrived in at the University of Texas, where Goodenough had moved the previous year from Oxford. After the usual stipulations regarding confidentiality, Goodenough agreed. He put Okada to work next to an Indian postdoc named Akshaya Padhi.
In hosting such researchers, Goodenough was part of the peculiar world of materials scientists, who at their best combine the intuition of physics with the meticulousness of chemistry and pragmatism of engineering. It is their role to dream up a new order from the existing parts in front of them.
Padhi and Okada began to tinker, searching for a battery with more energy and better safety than what had already been invented. They thought that a cathode with a crystal structure called spinel might work. In a regular cobalt cathode the atoms are stacked in layers, so the lithium ions stored in it can only travel in and out along these sheets. In a spinel, the way the atoms are arranged allows the ions to travel in three dimensions, so they can find multiple pathways in and out of the electrode, allowing it to charge up and discharge faster.
Perhaps Padhi and Okada could produce an even better spinel. They tried cobalt, manganese and vanadium, but none was quite right. Ultimately, they winnowed down the list to a final option—a combination of iron and phosphorus.
Goodenough was skeptical that they would end up with a spinel, and told Padhi so. Then the old man left for summer vacation. Goodenough arrived back to news. Padhi said the professor was right—he did not achieve the spinel structure. Instead, he had produced a different, naturally occurring crystal structure called olivine.
And he had managed to extract lithium from the olivine, and intercalate it back in. On inspection, Goodenough saw that the result was sensational. Goodenough caught wind of the subterfuge only the following year.
He was incredulous. A race of priority was joined. The Japanese and the Americans rushed out competing papers and patent applications. Then the complications worsened.
Asserting that his improvements had created yet another new material, Chiang and some partners launched A, a Massachusetts-based battery company. His stated aim was to sell a version of the lithium-iron-phosphate battery for use in power tools and eventually motor vehicles.
In , A sold shares in an initial public offering. Except, again, Goodenough. NTT admitted no wrongdoing. Goodenough received nothing from A One might see a certain poetic justice in what has happened since. In —just three years after the IPO—A ended up in bankruptcy. BYD has yet to make good on its stated potential. But Goodenough still regarded the outcome of the iron-phosphate dispute as a travesty. The battery world is full of exaggerators and one needs to stand up to them.
His brother, Ward, died about the same time at the age of When you are a great inventor in your 90s, there are lots of accolades. Goodenough Award for materials chemistry. But Goodenough seems most passionate about ending his career with a last, big invention. He is trying, of course, to make a super-battery, one that will make electric cars truly competitive with combustion, and also economically store wind and solar power. But the path he has chosen involves one of the toughest problems in battery science, which is how to make an anode out of pure lithium or sodium metal.
That would instantly catapult electric cars into a new head-to-head race with combustion.
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