Skill and scale up: lightweight, powerful and durable

How does a battery work?

They make our world rechargeable. They are light, can store a lot of energy and last a long time. About 30 years ago, pioneers laid the foundation for what is now indispensable in almost all areas of our daily lives: the lithium-ion battery. But how exactly is a battery built and how does it work? We explain this in our second blog post as part of the "SkillandScaleUp" information campaign.


It all started with the realization that lithium loves to make electrodes. The soft material, shiny when freshly cut, is the lightest metal on Earth and very reactive. The world's largest lithium reserves are in Chile and Australia. By 2020, they will account for nearly 75 percent of global mine production, according to DERA (2023). For a long time, however, lithium received little attention. It was not until the research of John Goodenough, Stanley Whittingham and Akira Yoshino, which was based on each other, that lithium received the attention it still receives today.

The structure of a lithium-ion battery

The discovery of a permanent power source (more here) laid the foundation for further battery research. At the very beginning is the realization that electrons are willing charge carriers. When they move, they create a voltage that triggers the flow of electric current. This is how a battery works. It consists of a negative electrode (the anode), a positive electrode (the cathode), a separator, the electrolyte, and the cell casing. Each component performs a different function:

  • The cathode is the positively charged electrode of a lithium battery. It usually consists of a composite structure containing lithium. These also usually contain nickel, manganese, cobalt or iron.
  • The anode is the negatively charged electrode of a lithium battery. It is usually made of carbon-based materials, (mainly graphite).
  • The separator prevents electrical contact between the cathode and the anode and also serves to provide spatial separation.
  • The electrolyte provides the flow of ions. Charged Li-ions can migrate in it, i.e. from the cathode to the anode and vice ver
  • The current arresters are made of copper and aluminum and conduct the electrons from the cell to the load (discharging) or from the power source to the cell (charging).
  • The housing protects the inside of the cell from external influences and prevents the electrolyte from leaking. The housing is usually made of steel or aluminum.

When a battery is used, the following happens: Negatively charged particles called electrons are released at the anode. They migrate to the cathode - not through the battery, but around it. This migration generates electricity. Conventional batteries, such as those found in remote controls, need to be replaced when all the electrons have migrated from the anode to the cathode. In lithium-ion batteries, however, the electrons move back and forth.

© Fraunhofer FFB
A lithium-ion battery is made up of various components.

The pioneers of the lithium battery

But it was a long way to the lithium-ion battery we use today in laptops, cell phones and electric cars. English-American chemist Stanley Whittingham was the first to build a pure lithium battery. He used titanium disulfide as the cathode material. The bronze-colored powder has an electrical conductivity comparable to that of semi-metals. It is layered, which is good for absorbing lithium ions without changing the crystal structure of the material. For the anode, he used metallic lithium. But it is very reactive. When the battery was discharged, the Li-ions migrated to the cathode; when it was recharged, they migrated back. But there was a problem: with each charge, dendrites formed on the anode. These resemble a needle-like structure. As soon as the dendrites penetrated the separator between the two electrodes and made contact with the cathode, a short circuit occurred. The batteries exploded.

The second founding father of the battery, John Goodenough, continued Whittingham's research and was able to double the voltage of the batteries from 2 to 4 volts by using lithium cobalt oxide. The advantages of lithium cobalt oxide are better electrical conductivity and higher energy density compared to titanium disulfide. Ultimately, however, it was Akira Yoshino of Japan who developed the first commercial lithium battery in 1985. Unlike Whittingham and Goodenough, he focused on the anode and relied on petroleum coke instead of reactive lithium. This carbon material, like crystallite cobalt oxide, can hold lithium ions in the cathode. He also incorporated a thin membrane to separate the cathode and anode materials. This prevents the battery from overheating before it can catch fire. This made his battery more stable than other rechargeable batteries being developed at the time. Today, it is hard to imagine a world without lithium-ion batteries. The demand is correspondingly high.

Global demand for battery cells increases

The intensive development activities and the resulting boom in demand from the e-mobility sector have contributed to a huge increase in the price of lithium. For example, each electric car requires between 5-10 kg of lithium, as approximately 100 grams of lithium are needed per kWh of energy storage capacity. A corresponding price increase can be observed in the market:  March 2022 alone will see a 1000 percent increase over December 2020, according to DERA data (2023).

Global demand for battery cells is expected to grow from 400-500 GWh per year today to 2500 GWh per year by 2030. This means that enough cells will be produced each year to store 2500 GWh of energy. The cells produced will be able to store as much electricity as 8.620.689 households consume in a year.

Due to its specific properties, lithium is expected to remain an indispensable and irreplaceable key component in rechargeable batteries for decades to come.