How has lithium battery technology changed our daily life?

brown-framed-light-bulb

The invention of lithium battery is not the inevitable result of the development of human science and technology, but a miracle.

If without the heroic epic contributions of M. Stanley Whittingham and John B. goodenough, maybe we were still living in a world without lithium batteries!

Goodenough to win the Nobel Prize is stand high in popular favor.

Lithium battery cell with plug

Electric vehicle before lithium battery

The invention of electric vehicle is actually earlier than that of internal combustion engine vehicle, and it still has an advantage in market share until 1912.

This is the 1912 electric car AD: victorian era cars:

1912 electric car AD - victorian era cars

Later, due to the slow progress of battery technology, it was eliminated by history and gradually forgotten by people. Normally, when a technology line is eliminated, it will die and never emerge, such as LCD TV vs plasma TV.

The reason why electric vehicles can return to the stage of history in a hundred years is that there are many heroes in the history of lithium-ion battery development, and the breakthrough of epoch-making technology with fantastic ideas, which has helped the electric vehicles to survive.


Lithium solves the problem of “too low energy density of battery”

In 1859, the French Planté invented the classic lead-acid battery, which is a very successful invention and is still widely used today.

Lead acid battery structure
Lead-acid battery structure

However, if it is used in the car, there will be a huge problem: the energy density is too low!

How low is it? Give the following picture to understand intuitively: in the lower left corner is the lead-acid battery. Compared with the current common ncm622 lithium-ion battery, its weight energy density and volume energy density are about four times lower.

The energy density of lead-acid battery is in the lower left corner: thermal runaway mechanism of lithium-ion battery.

thermal runaway mechanism of lithium ion battery

The application scenarios of automobile are quite special:

  • It is sensitive to volume, and no one wants to sacrifice the space of cockpit and trunk to install batteries;
  • It is sensitive to weight. If the energy density of the battery is too low, you may have to face the dilemma of 1 ton Car + 2 tons battery to run 500 kilometers. This is not only uneconomical, but also unacceptable from the perspective of environmental protection!

Similar to lead-acid battery, the energy density of Ni-Cd battery and Ni MH battery has not improved much. If we don’t invent new high energy density batteries, electric vehicles will never popular.


Why is the energy density low?

We know that battery charge and discharge can be understood as redox reaction.

Junior high school chemistry knowledge tells us: the chemical properties are mainly determined by the outermost electrons, and the inner electrons are all not working; it’s nothing if the electrons are very light, but in order to balance the charge, the inner electrons that don’t work also need to be equipped with very heavy protons.

The chemical properties of atoms are mainly determined by the outermost electrons: rutherford model of atom class 9th.

rutherford model of atom class 9th
rutherford model of atom class 9th

By reading the periodic table of elements, it is easy to find out that lead (PB) is in Row 6, with 5 layers of electrons not working; nickel (Ni) is in row 4, with 3 layers of electrons not working. This is determined from the perspective of atoms: the energy density potential of lead-acid battery, nickel cadmium battery and nickel hydrogen battery is limited!

the periodic table of elements
the periodic table of elements

In order to reduce the number of lazy one and improve the overall efficiency, we still look for potential one from the first two lines of the periodic table: hydrogen helium lithium beryllium boron, carbon nitrogen oxygen fluorine neon.

Oxygen and fluorine are oxidants, which can be excluded; helium, neon and nitrogen are inert or quasi inert gases, which can be excluded; carbon and hydrogen are actually petroleum, which have been used, and can not be used as rechargeable batteries, lets exclude them.

Why is it so difficult to improve energy density of batteries?

Then only lithium, beryllium and boron are left. Their electron transfer number / atomic weight are 14%, 22% and 28%, respectively. Consider two more factors:

  • The potential of lithium electrode is the lowest of all element periodic meter: the voltage is the highest when it is made into a battery; if the same number of electrons are transferred (the same current), the corresponding power is also the highest.
  • The reserves of lithium are relatively high: as shown in the above figure, the abundance of lithium in the earth’s crust is one order of magnitude higher than that of beryllium and boron.
  • There may be other factors, but I don’t know. Anyway, we have reached a consensus: in this space-time dimension of God, the rechargeable battery with the highest energy density is probably based on lithium element!

Whitingham: “farewell to chemical reaction” lithium-ion battery

Charging / discharging is accompanied by chemical reactions, such as when the lead-acid battery is charged:

PbSO4+2H2O+PbSO4=PbO2+2H2SO4+Pb

In the above chemical reaction, lead sulfate has become a “Lead single substance” and lead oxide, which means the breaking and recombination of chemical bonds and the great change of material structure.

Another familiar example of material structure is carbon with different structures:

diamond material structure
diamond material structure
graphite material structure
graphite material structure
C60 material structure
C60 material structure
carbon nanotubes material structure
carbon nanotubes material structure

So, “graphite to diamond” is a physical reaction or a chemical reaction?

Early lithium battery work also accompanied by the breaking and recombination of chemical bonds, which is called “lithium conversion”.

The negative electrode is usually lithium metal, and the reaction is as follows:

yLi+XLiyXyLi+X↔LiyX

This is the chemical reaction of “lithium dendrite” that causes the spontaneous combustion of electric vehicles.

In the current lithium-ion batteries, the lithium dendrite phenomenon only occurs in a few abnormal situations such as super fast charging and overcharging, which has such a great harm.

In the early days, the lithium battery took “lithium dendrite” as the basic reaction. It like took arsenic as a simple meal. Isn’t it dangerous?

Indeed, Moli energy, a Canadian company that sold millions of early lithium batteries, went bankrupt in a year due to several security incidents. After NEC acquired Moli energy in Japan, it was found that almost all of the early lithium batteries with “lithium dendrite” as the basic reaction had failure and safety accidents after 5000 cycles!

The safety accident of lithium battery with lithium metal as negative pole is not accidental but inevitable, not individual but all! This conclusion puts lithium battery in the cold, and the industry is pessimistic again and again. At this point in time, almost no one will believe that electric vehicles can return to the stage in decades!

If the technology route of “lithium conversion” is very difficult, can we avoid it? All rechargeable batteries at that time, including lead-acid batteries, nickel cadmium batteries and nickel hydrogen batteries, were based on the “conversion” reaction!

M. Stanley Whittingham pointed out another technology path besides “lithium conversion”: lithium intercalation.

It is easy to understand that with special layered materials as hosts and Li + as guests, they can be intercalated or detached at will without affecting the physical structure of the host.

When the positive and negative materials are hospitable hosts, lithium ions can come and go freely:

lithium battery working principle
lithium battery working principle

In the intercalation system, lithium ion does not have to undergo painful conversion. After “farewell to chemical reaction”, lithium ion becomes much more free.

Of course, in the intercalation, lithium ions only appear to have physical movement, but in essence, they are still chemical reactions.

Intercalation brings many benefits, which greatly improves the reversibility of charge discharge reaction, and avoids using lithium metal as negative electrode, which improves the safety.

From lithium conversion to lithium intercalation is the technological revolution of lithium battery. Because of this contribution, Whittingham is known as the “founding father of rechargeable lithium ion battery”.

Note:

1) Whitingham pointed out that the mechanism of lithium embedding was prior to Moli energy (1976), but after the accident of Moli energy (1989), lithium-ion batteries with both positive and negative electrodes adopting lithium embedding mechanism were paid attention to, thus stepping onto the historical stage.

2) In fact, Moli energy did not ignore whitingham’s contribution. The positive electrode was made of lithium embedded materials, but the accident negative electrode was made of lithium metal based on lithium conversion.

3) Akira Yoshino, the third Nobel Prize winner, is the key figure in replacing the anode material with graphite carbon with lithium embedded mechanism.

As a historical story, for the convenience of narration and the control of length, this answer does not tell in strict chronological order; at the same time, it omits a large number of details and some scientists who have made significant contributions, but this does not mean that they are deliberately ignored.

4) Intercalation is superior in electrode potential, but inferior in energy density.

Dominant in electrode potential, but inferior in energy density

Dominant in electrode potential, but inferior in energy density
Dominant in electrode potential, but inferior in energy density

It is easy to understand that if lithium metal is used as the negative electrode to store lithium ions, the material utilization rate will be very high. Because of this, the technology route of lithium metal battery based on lithium conversion is difficult, but for the lithium battery with higher energy density, now scientists are still sticking their heads out and working on it one after another.

Whitingham points out the direction of intercalation, but it’s a long way from making lithium-ion batteries. The second hero in the history of lithium battery appeared, John Bannister Goodenough.

The most admirable thing about Mr goodenough is:

Only after he was over 50 years old, he put into the research of lithium battery, and with his strength, he found most of the key positive materials:

LiCoO2 lattice structure
LiCoO2 lattice structure
LiMn2O4 spinel structure
LiMn2O4 spinel structure
LiFePO4 olivine structure
LiFePO4 olivine structure

Now 98 years old, Mr goodenough is still fighting on the front line of scientific research, hoping to make a breakthrough for the next generation of lithium-solid batteries.


Other people / companies promoting ev

Whitingham’s and goodenough’s scientific contributions have laid the theoretical and technical foundation for the great development of lithium battery.

From a historical point of view, the great development of lithium battery can not only rely on scientific research, but also on industry. There are also many heroes in the industry, limited to my length, whose stories can only be summed up in one sentence here.


Key figures to promote the electric vehicle:

Soichiro Honda: founder of Honda. In the 1970s, when the clean air act was blocked by general motors by the California Air Resources Commission, the invention of new combustion chamber technology helped California prove the rationality of the act, so that the emission act could continue to be implemented.

Tokyo Electric Power executive. At the beginning of the 21st century, under the unfavorable environment of the U.S. and Japan’s automobile industry, the joint efforts of Mitsubishi automobile and Subaru automobile to implement the electric vehicle plan indirectly prompted Nissan to launch leaf electric vehicle.

Elon Musk: almost at the same time as Nissan LEAF, a large-scale Panasonic 18650 battery has been successfully used to build a popular electric vehicle in the market.


Sony: the key company to promote the commercial use of lithium-ion batteries

In 1991, Sony released its first commercial lithium-ion battery, which was later widely used in cameras and mobile phones.

Lithium-ion battery has helped the consumer electronics industry and changed the whole world; in turn, the huge market of consumer electronics industry has greatly helped the rapid development of lithium-ion battery technology and industry.

If there is no boost from the consumer electronics industry, at the beginning of the 21st century, there may not be a lithium-ion battery that can meet the application standards of electric vehicles at all – the consumer electronics industry helps the lithium-ion battery to progress from 1 to 10, so the electric vehicle industry has the opportunity to continue to advance on this basis.

Sony has also contributed to the development of electric vehicles. Sadly, there is no Sony in the lithium battery industry now: Sony always makes amazing products and technologies ahead of time, but it can’t hold on to the day of winning the fruits.

Reference

Picture source: Lithium ETF Powers Down on Morgan Stanley’s Dismal Forecast

The article is forwarded from: How has lithium battery technology changed our daily life? (Chier Hu from Quora)

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