All About Batteries

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Podcast Transcript

The odds are quite good that somewhere around you right now as you listen to me speak these words, is a battery. 

Whether it is in your smartphone, earbuds, automobile, smoke detector, or laptop, batteries have become ubiquitous in the modern world. 

The origins of chemical batteries go back thousands of years before people knew what electricity was or what they could do with it. The future of batteries looks even brighter as more devices will require more and better batteries.

Learn more about batteries, how they work, and how they have developed over time on this episode of Everything Everywhere Daily.

Everyone listening to this, I’m sure is familiar with batteries. You use devices that have them, you’ve probably had to replace them, and every so often, you have to buy them or recharge them. 

Most people, however, don’t know what is going on inside of a battery or how modern batteries were developed. 

So, let’s start by going way back in time, about 2000 years, to the city of Baghdad. In 1936, a device was discovered that has been dubbed the Baghdad battery. 

It was nothing more than a clay pot with a copper tube and an iron rod. The inside of the pot was found to contain some acid, which could have been from vinegar or wine. 

The initial theory published about the device’s purpose claimed that it was for electroplating. It would use weak electricity to put a thin layer of metal over another metal. 

Other theories hold that it just created a weak current that people could touch and could have been used for medicinal or religious purposes. 

These theories have been disputed, and most archeologists don’t think the device was a battery. 

However, on several occasions, people have recreated the Baghdad battery and they were able to produce a weak current. This was done on an episode Mythbusters and they managed to get it to work. 

So if it wasn’t a battery, it did actually work as a battery, and if it was a battery, then we have no evidence that anything ever came of it. 

Fast forward to the late 18th century for the next advancements in batteries. 

In the late 18th century, scientists were discovering what electricity was and how it worked. Early researchers were able to store electricity in what was known as a Leyden jar. 

A Leyden jar is just a glass jar that stores and discharges electrical energy using a glass jar lined inside and out with metal foil. 

Technically, it wasn’t a battery but a capacitor. Capacitors store electricity in an electric field. 

Benjamin Franklin worked in Lyden jars, and when he hooked multiple Lyden jars together, he called them an electrical battery. He took the name from a collection of artillery that are used together. 

The word battery, meaning multiple things working together, stuck, but it was later used to mean something slightly different from a capacitor. 

The first true battery was created in 1800 by the Italian electricity researcher Alessandro Volta. He created a device known as a voltaic pile. His device consisted of alternating discs of zinc and copper with pieces of cardboard soaked in brine between the metals.

His device had all of the elements we think of today as a battery. 

This would be a good time to describe what a battery is and the basics of how a battery works. We have to start with the question: what is an electric cell?

A cell stores electrical energy chemically. A basic cell requires three parts: an anode, a cathode, and an electrolyte. 

The anode is the negative terminal of a cell is consists of some substance that wants to give up its electrons easily. Lithium is a good example of such a substance. In Volta’s voltaic pile, the anode was zinc. 

The cathode is the positive terminal of a cell, and it consists of something that wants to hold onto electrons. In Volta’s pile, copper served at the cathode. 

In between the anode and the cathode is some substance that serves as an electrolyte. An electrolyte can be a solid, liquid, or gel that transports electrons between the anode and the cathode. In Volta’s pile, the electrolyte was saltwater that permeated the cardboard. 

When the anode and cathode are connected, a circuit is created, and the electric potential between the anode and cathode causes an electrical current.

That, at its core, is all an electrical cell is—anode, cathode, and electrolyte.
A battery is just a collection of cells in series or in parallel.

Volta’s voltaic pile was able to provide a constant current of electricity, which was something you couldn’t do with a Lyden jar, which would expend its charge all at once. This allowed researchers to study actual electrical currents, not just static electrical charges. 

As much of a leap as Volta’s battery was, there were still serious limitations. 

Over the course of the 19th century, many innovations were made to improve batteries. 

In 1836, John Frederic Daniell invented the Daniell cell, which was more stable and produced a steadier current than Volta’s pile. 

There were over half a dozen advancements in battery design that improved the current and voltage of batteries. However, they all shared one fundamental problem. Once the battery was assembled, it discharged, but it couldn’t be recharged. These are known as primary batteries. 

This changed in 1859 with the invention of the lead–acid battery by the French physicist Gaston Planté. The lead acid battery used a lead anode and a lead dioxide cathode immersed in sulfuric acid as the electrolyte. 

The great thing about the lead acid battery was that once it was discharged, it could be recharged by running the current the other way. The lead acid battery is fundamentally the same type of battery that can be found in most automobiles today. 

Further developments in battery technology have mostly involved the use of other substances, as anodes and cathodes. There were also batteries that used an alkaline electrolyte rather than an acid electrolyte. 

In 1881, the first commercially successful dry cell battery made of zinc and carbon hit the market. It didn’t require a liquid electrolyte as most batteries did.

Throughout the early 20th century, the world became more and more electrified, and there were more and more devices and uses for electric batteries. One of the more popular batteries in use during this period was the zinc-carbon battery. 

This period also saw the introduction of standard battery sizes. The National Carbon Company introduced the D cell in 1898, and the Eveready Battery Company introduced what we know as the AA battery in 1907 and the AAA battery in 1911. 

Zinc–carbon batteries didn’t have a very long life. The next big innovation was the creation of the alkaline battery. 

In 1949, a Canadian researcher named Lewis Urry was working for the Eveready Battery Company. Urry was tasked with finding a way to improve the lifespan and performance of existing zinc-carbon batteries. 

He experimented with different materials and formulations, ultimately discovering that a manganese dioxide cathode and a zinc anode, when used with an alkaline potassium hydroxide electrolyte significantly improved performance.

These new alkaline batteries lasted five to eight times longer than zinc-carbon batteries.

Alkaline batteries were a huge improvement. They are still used today as they have a high energy density and are very affordable. 

However, they also had a downside. They couldn’t be recharged. They had to be purchased and disposed of, and many of the early alkaline batteries used mercury which was a problem in landfills. 

What was desired was a battery that had a high energy density and was rechargeable. Ideally, it should also be lightweight and affordable. 

A massive step towards this goal was taken with the development of lithium batteries. Lithium is the third lightest element on the periodic table, and it also has the highest electrochemical potential of any metal.

Attempts at lithium batteries began in the first years of the 20th century. However, it wasn’t until the 1970s that serious research began.  

The first lithium-based batteries came to market in 1991 as a joint project of the Sony Corporation and the Asahi Kasei Chemical Corporation. These batteries were known as lithium-ion batteries, and today the term encompasses an entire category of batteries. 

Lithium-ion batteries were truly revolutionary. They had a host of benefits over traditional alkaline batteries. 

For starters, they were rechargeable, which meant you didn’t have to buy new batteries every time they ran out of charge. They had a much higher energy density and can provide higher currents for longer periods in items that requires more current like power tools.

They have low self discharge, meaning if they are left alone, their charge will not disappear. Finally, they can be many in any number of shapes and sizes. 

Lithium ion batteries were responsible for the revolution in battery powered wireless devices over the last 30 years. Laptops, mobile phones, power tools, electric cars, and almost every other device is reliant on some form of lithium ion battery. 

Since their release in 1991, lithium ion batteries have continued to improve. Energy density has increased threefold while their cost dropped tenfold.

While lithium ion has ushered in a revolution in batteries, they are not perfect. The biggest weakness is that lithium ion batteries are a fire risk. Granted the risk is low, but if a battery is punctured the liquid electrolyte can escape which can cause a fire. 

Another problem is that dendrites can grow inside the electrolytes. Dendrites are solid fingers of lithium that can slowly grow. If they grow large enough, they can cross from cathode to anode and cause a short circuit.

Given the importance of batteries in the world’s economy, more research is being done on battery technology than ever before. Anyone who can come up with large-scale improvements in battery technology stands to make a fortune. 

One promising technology is solid-state batteries. 

Solid-state batteries are conceptually very simple. It replaces the liquid or gel electrolyte with a solid. Most people don’t realize that their electronic devices have a liquid inside them, but they do. Granted, the liquid isn’t sloshing around and is in very thin layers, but it is a liquid nonetheless. 

Solid state batteries have the potential to revolutionize batteries in the same way that lithium ion batteries several decades era. For started, they would be much safer as there is no risk of a leaking electrolyte. 

They would charge much faster, have a higher energy density, last longer, and they could operate at higher and lower temperatures. 

This would mean an electric car that only required half the battery size that current cars do resulting in decreased prices, or a battery of the same size that could go twice as far.

Perhaps even more importantly, a car could be fully charged in just a fraction of the time it currently takes.  

The same would hold true for all electronic devices that need to be recharged. 

Due to the weight and electrochemical potential of lithium, future solid-state batteries will still probably be lithium-based. 

However, not every battery application requires something lightweight that can charge quickly. Sometimes, you just want something cheap and forgo other battery attributes.

One such potential technology is known as an Iron-Air battery. As the name would suggest, an iron-air battery stores energy via the oxidization of iron with air, aka rusting, and then creates electrical energy by reversing the process.

Iron-air batteries are very heavy, and they don’t charge quickly, but then again, they don’t have to.  The use case for iron air would be providing electrical storage for the entire grid or just for homes. The batteries don’t have to be mobile, so weight isn’t relevant. Likewise, they would be connected to a power source all the time, so they would have plenty of time to charge. 

The biggest benefit of iron-air batteries is that they would be ten times cheaper than lithium-ion batteries. 

Solid state and iron air are far from the only new types of batteries being developed. There are also experiments being conducted on new substances like sulfur, which could also lead to dramatically improved outcomes. 

Battery demand is expected to grow dramatically over the next few decades. This is driving new exploration and mining efforts to discover new sources of lithium and rare earth elements. 

Since the creation of the first true battery over 200 years ago, batteries have steadily gotten better and become more important. This trend only seems to be accelerating. Decades from now, we will probably be using even more batteries that are dramatically better than the ones we have today.