Beyond Lithium-Ion: A Look at Alternative Battery Technologies
Welcome to the third edition of the Green Innovations Newsletter! This time, we're diving into the wild world of batteries. We'll take you beyond the popular lithium based batteries to explore ingenious solutions in battery tech that will challenge your imagination of what batteries are and make you go “wait, really, that's a battery?”.
We'll look at salt cocktails that extend the life of lithium batteries, batteries that use rust, batteries that store energy in the form of gravity, and flow batteries that operate by pumping liquid between large tanks. Let's dive right in.
Improving Existing Lithium-Ion Batteries
Existing battery technology is up for improvements as well. Researchers at TU Delft have found a straightforward technique for extending the lifespan of lithium-ion batteries used in electric cars and smartphones. By adding five salts to the current "cocktail" present in every lithium-ion battery, the researchers created a protective layer between the electrolyte, anode and cathode that stopped electrons from flowing while allowing lithium ions to carry energy.
The Dutch company Leyden Jar, that already has developed batteries able to store 70% more energy that are operational for 450 cycles of full discharging and charging, is going to test this new cocktail recipe for batteries. The goal for this new cocktail is to get to 800 cycles, almost doubling the lifespan of a battery.
As you can see from the above chart, we’re already facing a mountain of batteries that will be end-of-life in 2040 and it’s only increasing. Increasing the lifespan of lithium-ion batteries could lead to a reduction in the cost per kilowatt-hour of energy storage for electric vehicles and home battery systems. Longer-lasting batteries mean fewer battery replacements, decreasing the overall cost of ownership. This would help with the transition to renewable energy sources and electric vehicles, making them more accessible and affordable. The extended lifespan would also reduce the amount of waste generated from discarded lithium-ion batteries. 🤞
Read the scientific paper here.
Storing Energy in Gravity?
And now for something completely different. Have you heard about gravity batteries? The idea is pretty simple, but completely change the way you think about batteries and energy storage.
These batteries use power to lift a heavy weight high up into the air or deep down into a shaft. Then, when you need some juice, the weight gradually lowers and creates electricity in the process. 🤯
A Scottish company called Gravitricity has tested out their prototype at the Leith port, and it can generate 250 kW, which can sustain around 750 homes.
Gravitricity's demo unit can deliver full power in less than a second, which is valuable for operators that need to balance the grid second by second. The prototype is made of solid, single-motion components, which will result in longer-lasting energy storage, unlike lithium-ion batteries that lose capacity after being charged and recharged for years. Gravitricity's gravity battery can store between 1 and 20 MWh of energy, enough to power around 1,000 homes on a typical day. Although large enough gravity batteries are still some years away, the technology is evolving rapidly, according to experts.
Rusty Batteries
No, I’m not referring to discarded old batteries collecting rust, but to batteries that thrive on rust. There’s a type of battery called iron-air battery that uses oxidation, in simple terms - rusting, to store electricity and discharge it when necessary. The battery primarily contains iron, air and water. What’s common among all of them? They’re abundant, cheap, and non-toxic.
The battery charges by using an electric current to turn rust into iron, releasing oxygen (un-rusting, sort of). During the discharge cycle the battery takes in oxygen from the air to oxidize the iron to rust. That’s the basic principle.
Iron-air batteries can store enough energy to last for several days. Form Energy is building iron-air batteries that can store electricity for 100 hours. Contrast that with lithium batteries that can store only hours worth of energy. These batteries don’t run the risk of blowing up like lithium ones do.
They’re not without their drawbacks though. Iron-air batteries are large and heavy, and as a result they are less efficient than lithium batteries.
These batteries are perfect for complementing renewable power grids as they can provide a resilient power backup during multiple days of power outages or low renewable energy generation.
Who would’ve thought rust, of all things, would be driving a green innovation?
Make ‘em Bulbs Glow With The Flow
Most rechargeable batteries have all the active components (anode, cathode and electrolyte) in a single cell. Well, flow batteries are an exception. They have a distinct design that houses positive and negative electrolytes in tanks outside the cell and operate by pumping the electrolytes through a cell, where they react. The electrolytes flow through the cell and hence the name.
The electrolytes are continuously pumped through the cell during both charge and discharge cycles. A power source, like a windmill or a solar farm, charges the battery by moving electrons from the positive electrolyte (anolyte) to the negative electrolyte (catholyte). During discharge the electron flow reverses, generating electricity.
Flow batteries last for decades, are safe as they use non-flammable electrolytes, environmentally friendly using non-toxic materials and can be easily recycled. They are also scalable - the larger the tank, the more electricity that’s stored. They however have a low energy-density and hence have a larger footprint than a lithium battery of the same energy capacity.
Flow batteries come in various flavors, depending on the electrolytes used. Elestor Solutions has developed a flow battery with hydrogen and bromine, both abundant, as active materials. Redflow on the other hand uses zinc and bromine. Redflow has built a flow battery that can store 2MWh energy - enough to power 70 homes for a day.
Until next time…
In addition to these there are the thermal batteries, some of which we covered in the previous edition. Although most of these don’t fit the dictionary definition of a battery, they are pushing the boundary on what a battery can be.
That’s all the juice we’ve got in our batteries for now. But you bet we’ll be back with some crazy wild stuff to blow your mind.
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