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The promises and pitfalls of modern battery tech
Tesla Cybercab at Santana Row, in San Jose, California USA. Photo: Dllu/Wikimedia Commons
Elon Musk’s October Cybertaxi event displayed a dazzling array of new gadgets that will likely be accessible to or most beneficial for the ultrawealthy. Although Tesla markets itself as environmentally conscious, the focus that night, and at so many other tech companies lately, was on AI. Setting aside the fact that the “autonomous” humanoid robots were piloted by humans and that Musk has failed for years to follow through on his promise of delivering full self-driving, something that was particularly noticeable was the paucity of power chords.
Musk’s effervescent march towards a sustainable future seems to be ignoring the toll the batteries used in his products are taking on the environment, as well as the glass ceiling their performance has seemed to hit. I remember my excitement upon hearing that the Roadster and Cybertruck would have a 600-mile range. What Musk delivered was a 300-mile Cybertruck with an option to sacrifice half the truck bed to make it closer to 400 miles than 600 and no roadster.
On top of that, lithium and cobalt mining cause land, air and water pollution. Every ton of lithium mined results in 15 tons of CO₂ emissions, and there’s a possibility that lithium demand will outgrow the global supply. Unfortunately, this is currently the best battery technology available.
A brief history of batteries
Humans have known about electricity long before Benjamin Franklin shocked his finger on a key attached to a kite. Thales of Miletus used amber to generate static electricity in the sixth century BCE and assumed it meant inanimate objects had souls, having little understanding of it otherwise. Some believe the “Dendera light,” an ancient Egyptian relief depicting what looks like a lightbulb hooked up to a battery, would have been the first of its kind, though this is mostly because it happens to look like a bulb; no evidence to corroborate this was ever discovered. The Baghdad Battery, made sometime between 150 BC and 650 AD in present-day Iraq, was confirmed to carry charge on the Discovery show Mythbusters and by Smith College. It’s unclear what it was used for, but experts speculate electroplating or electrotherapy.
Batteries really got jump-started in the 1800s with Alessandro Volta’s voltaic pile. The voltaic pile comprised zinc and copper discs separated by cardboard or cloth soaked in salt water, acting as an electrolyte. The electrolyte creates a chemical reaction where the salt water breaks down the zinc, facilitating its pass of electrons to the copper, but only if the circuit is complete. The energy from the electrons can then be harnessed through copper wire. Most of the time, it was used for other experiments, like separating periodic elements. You can easily make one at home.
Eventually, the pile was improved upon by replacing the salt water with an electrolyte paste and incorporating the zinc (anode) and the copper (cathode) into the hull of the battery, which held the electrolyte. And now we’ve come to something resembling the product currently available at Walgreens. Alkaline batteries, including double-As, use manganese dioxide and carbon as a cathode surrounding the powdered zinc anode, which is mixed with a potassium hydroxide solution electrolyte. A brass pin leading to the negative side of the battery collects the electrons. These batteries are prone to leakage, especially once depleted. Since usage gives off hydrogen gas, if left in a device for too long, this can rupture the casing. The casing can also rust or sustain damage. If this happens, the electrolyte can leak out and form a crystalline substance with CO₂ in the air. While caustic and corrosive, the electrolyte is less dangerous as potassium carbonate; however, if you find a way to come into contact with potassium hydroxide, a trip to the hospital might ensue.
Then there are rechargeable batteries. When you use a battery, you’re harnessing energy from the electron flow. The electrons must always flow to complete the circuit, but their energy is used to power the device. There is only so much energy that can be squeezed out of a certain combination of anodes, electrolytes and cathodes, but some materials can easily be reverted using the energy from the electrons coming out of a wall socket. When you plug in these batteries, energy is converted to the proper voltage and amperage by the charger, which causes the chemical reaction to work in reverse. Once the ions and electrons are back in their original positions, it is recharged and ready to use again.
If you thought that was complicated, get ready for lithium-ion (Li-ion) batteries. These batteries use a graphite anode, which acts as a lattice for lithium atoms. Once the circuit is complete, the lithium’s loose electrons have a path to the cobalt through the device circuitry. Simultaneously, the ionized lithium passes through a gel electrolyte into the lithium cobalt oxide cathode, where its electrons have already embedded in the cobalt. When the charger is introduced, the process is reversed.
Where battery technology might be taking us
If you’ve ever tried to do the cost-benefit analysis for buying an EV, you’ve probably wished Li-ions performed a little bit better and didn’t run the risk of exploding. You are not alone. Several alternatives to Li-ion batteries are on the table. NASA has developed a solid-state battery that doubles the energy density of current Li-ion batteries. Also, since its electrolyte is solid, it can be formed into more shapes, greatly reducing the risk of explosion. It will actually continue to function if fully punctured and can handle more extreme temperatures than Li-ion batteries. The major caveat is the discharge rate is much lower for solid-state batteries, meaning that even though it holds more energy, it trickles out of the battery more slowly. NASA’s team claims to have increased the discharge rate by 10%, though it’s unclear if that is enough to power a road vehicle, let alone an aerial one, which is what NASA wants the batteries for.
There are also sodium-ion batteries (Na-ion) and Lithium-sulfur (Li-S) batteries. Na-ion batteries are made from a much more abundant resource: salt. They can charge and discharge faster, have better temperature tolerance, and are less prone to thermal runaway. Despite these benefits, they have a lower energy density and shorter cycle life, making them less practical for mobility use. Li-S batteries have an energy density that is more than twice that of the strongest Li-ion batteries and use less precious metals, particularly nickel, manganese and cobalt. Though these are also more resistant to thermal runaway and function in extreme temperatures, they are less stable otherwise, prone to self-discharge and have a limited cycle life.
Despite the setbacks of these cutting-edge technologies, companies are investigating their potential to revolutionize the market. Mercedes says it will have a solid-state battery ready for production by the end of the decade using a silicone anode. Natron Energy has plans for a Na-ion factory in North Carolina, and the battery startup Lyton proposed to build a Li-S factory in Nevada by 2027. What all these companies have in common is the promise of a product that is not currently available, much like Musk’s bold claims at his Robotaxi event — claims which, as of late, have had questionable merit. America’s economy almost necessitates this behavior since businesses require media attention and funds from investors to stay afloat. As a consumer, however, one shouldn’t count on these technologies to cause a massive sea change overnight. It’s anyone’s guess when they’ll actually be feasible.
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