The relationship between silver and batteries goes back centuries. But we aren’t just talking about the batteries that go into powering your flashlight at home. Silver is such a powerful tool for energy production that it was used in the batteries of the lunar module of the Apollo space program in the 1960s. That’s because silver has the highest electrical conductivity of all metals.
Now, with the advent of batteries specifically for electric vehicles (EVs), silver is becoming all the more important in providing a safer alternative to their lithium-ion counterparts while helping reduce the world’s dependence on fossil fuels.
History of Silver in Batteries
Historians estimate that battery technology dates back to around 1800 in Italy, where Alessandro Volta invented what is known today as the first modern battery. Volta used a zinc and copper electrode, but it is also apparent that he experimented and utilized silver as a replacement for copper as well. However, Volta had a problem. When using silver and zinc together, he found that the electrical conductors deteriorated quickly, making the product less usable. But in the 1920s, this problem was solved by Frenchman Henri André, who created a membrane to separate the battery’s two electrodes, thereby making the first practical and usable silver battery.
While these silver-zinc based batteries were durable, reliable and light, there was only one problem: silver is expensive. That’s why silver batteries today are mostly used in smaller batteries, where lots of energy needs to be packed into a small profile.
Over a century later, in the 1950s, silver-zinc was first introduced as a method of energy storage for their use in torpedo propulsion and submarines, which was primarily researched by the United States and the Soviet Union militaries. Their use in these applications lives on today in most non-U.S. Navy torpedoes.
A decade later, NASA took the same silver-zinc batteries and used them in the Apollo space missions. These batteries were one-third the size of the previously used nickel-cadmium batteries and were significantly lighter, which was crucial for a successful space launch. In fact, silver-zinc worked so well on the Apollo missions that it became the go-to battery for space programs around the world, including:
- Portable Life Support System (PLSS) for lunar exploration
- Mars Pathfinder Lander
- Russian Sputnik spacecraft
- Delta II and IV, and Atlas V, unmanned launch vehicles
Then, in 1972, NASA partnered with the Douglas Aircraft Company to develop this technology even further. The result was a rechargeable silver-zinc battery that lasted for 500 charging cycles and was durable enough to last under heat sterilization. But this was quickly outdone by nickel-cadmium batteries which could last more than ten times longer.
It wasn’t until the 1990s that the technology company ZPower put silver-zinc batteries back on the map. Working with the research already developed by NASA, ZPower significantly improved upon the capabilities of silver-zinc. According to NASA, this was the breakthrough needed to take silver-zinc batteries into the next century:
“The company has improved all four active components of the battery: the two electrodes, the electrolyte, and the separators, earning some 100 new patents. The batteries can now survive up to 1,000 discharge cycles without losing significant capacity.”
Current State of Silver in Batteries
Silver is being used more and more in batteries across a wide range of applications mostly due to their long life cycle. These applications include:
- Hearing aids
- NASA space crafts
Many technology companies work with silver to improve the quality and life cycle of batteries. For instance, ZPower has developed a silver-zinc based hearing aid that builds off the same technology used by NASA. “What we’ve done at ZPower is take that chemistry that NASA did a lot of development on, along with the military, and moved it into the commercial sector,” says the company’s president Ross Dueber. ZPower’s silver-zinc battery can last up to 1,000 discharge cycles without degradation, a significant improvement on the hearing aid batteries of old.
There are two different types of silver-based batteries:
These are small-sized batteries that use silver oxide as the cathode and zinc as the anode. These were the batteries used on the Apollo space program for the lunar module and lunar rover and military use in torpedos. They are advantageous because silver oxide can pack high levels of energy into low-weight battery sizes. For this reason, silver oxide is often used in button cell batteries for watches, cameras, and hearing aids. However, silver-oxide can be more expensive than alternative battery options.
According to recent statistics, silver-oxide batteries account for 30% of all primary battery sales in Japan.
Silver-zinc batteries have historically been used in more specialized applications, although they have made their way into laptop batteries and hearing aids in recent years. Historically, these batteries had the highest energy density of all battery types. It’s estimated that new technological advancements in silver-zinc can increase their energy efficiency to provide 40% more run time than lithium-ion batteries. However, they are generally more expensive. This increase in efficiency would make silver-zinc the battery that provides more energy per ounce than any other battery on the market.
Silver vs. Lithium-Ion Batteries
While lithium-ion batteries have been the go-to solution for several decades, they don’t come without their drawbacks. Lithium-ion batteries are pretty fragile and are highly reactive with oxygen and moisture. Damaged lithium-ion batteries have a history of causing fires and other safety risks. These batteries also age quickly and need to be replaced, making them a less than optimal choice for environmental reasons. Furthermore, lithium is a finite resource.
Compared to lithium-ion batteries, silver has the advantage in many categories:
Silver in electric vehicle batteries
When it comes to electric vehicles (EVs), the primary technology used for power is solid-state batteries. These batteries can increase energy density and allow for more range on a single charge. However, there is still a high battery failure rate after multiple charges that make these batteries still far from perfect.
There may be a solution to this problem with the help of silver. Currently, the technology company Samsung is working on introducing a silver-carbon film into a pouch cell that would increase the energy density of traditional lithium-ion cell batteries. This innovation could help to protect the battery from dendrites, which are crystals that form and damage the battery. The result of this innovation could lead to significant improvements for EV efficiency, increasing their range to as much as 500-miles for over 1,000 recharges, giving the new solid-state battery with silver a life of 500,000 miles.
While Samsung doesn’t believe this technology will be available soon, it proves that silver is an essential piece of EV technology for the future. Because Samsung is the leader in developing this technology, this technology may find its way into consumer goods like laptops, smartphones, and other consumer electronics.
How Does Battery Development Affect Silver Demand?
Silver has long been used in batteries, but it hasn’t been until the past few decades that its usage has grown thanks to technological advancements and research. As a result, the demand for silver is likely to change with its growing use in batteries. This demand is especially true in the EV market, where silver may hold the key to longer-lasting solid-state batteries.
Lithium-ion batteries may have once outshined silver batteries, but new technological innovations are bringing a new source of silver demand back to this industry. For precious metals investors, it’s important to know these trends and technology affecting the demand for silver. As manufacturers continue to transition to silver-based batteries for EV and other, more general applications, so too will its demand in the market. As with any new or growing source of demand, this growing revolution in battery technology could generate higher long-term silver prices as a result.