Energy storage
Lithium-ion battery technology is ubiquitous. It powers the device you are using to read this perspective, for example. Rechargeable lithium-ion batteries launched the portable technology revolution almost 30 years ago.
We are in the early stages of the second era of this technology, the electrification of transportation. Electric cars, buses, bikes, scooters, skateboards, even trains and ferries, are all being adopted to eliminate pollution in urban areas and, as clean energy increases on the grid, to enable a carbon-neutral future free from fossil fuels.
What factors have led to this second revolution? The major driver has been the falling cost of lithium-ion batteries, which have dropped from over $1000 per kWh of stored energy to less than $150–200 per kWh in the past decade. However, it may be surprising to learn that the fundamental materials and operation of these devices is not drastically different than the first commercial cells produced by Sony in 1991.
Electric cars, buses, bikes, scooters, skateboards, even trains and ferries, are all being adopted to eliminate pollution in urban areas
To understand the implications and future directions of this technology, we need to go a bit deeper first. A lithium-ion battery is a small chemical reactor comprising a cathode and an anode. As you use an electronic device, lithium ions move from the anode to the cathode while electrons move through a circuit, providing energy. When you charge the device, energy is put into the battery to move the lithium ions and electrons back to the anode, ready for the next use. The 2019 Nobel Prize in Chemistry was awarded to three scientists who created this technology: Stan Whittingham for the concept, John Goodenough for cathode development including lithium cobalt oxide, and Akira Yoshino for the graphite anode. Goodenough’s lithium cobalt oxide and Yoshino’s graphite are still in use today in most portable electronics.
If we are still using the original chemistry, then the increased performance and cost reductions have thus come from better cell engineering and manufacturing. Of course, these solutions have natural limitations and we are reaching a plateau where optimization has peaked. What, then, does the future look like for lithium-ion batteries and energy storage? The major shift that is well underway is the gradual removal of cobalt from the cathode, and replacement with nickel. Cobalt is relatively rare, expensive (and unstable in cost), and toxic. There are also serious ethical concerns around the cobalt supply chain and mining practices, with the majority of resources coming from the Democratic Republic of the Congo. Nickel helps to alleviate some of these issues, and can actually increase the battery performance, though so-called “Nickel-rich” cathode adoption is already straining the nickel supply and leading to price increases.
Cobalt is relatively rare, expensive (and unstable in cost), and toxic. There are also serious ethical concerns around the cobalt supply chain and mining practices, with the majority of resources coming from the Democratic Republic of the Congo.
The transformation in cathode materials is particularly important as Nickel-rich materials are key to increasing the driving range of electric vehicles. Although we are very much in the early stages of electric vehicles, with around 2% adoption in the US, the automotive lithium-ion battery market has already surpassed that of all portable electronics combined. At 40–80 kWh, one fully electric vehicle has a battery that is equivalent in size to about 10,000 laptop batteries. When you consider that the electric vehicle market is expected to grow ten-fold by 2030, it is almost like starting from scratch in terms of the scale of resources and infrastructure for materials mining, production, sales, and recycling.
Besides the changing magnitude of this technology, there could be major changes to the materials used in lithium-ion batteries as the diversity of applications increases to include grid-based solar+storage, frequency-balancing, load shifting as well as new handheld and household devices that have different requirements in terms of power, charging time, weight, and lifetime. Staying abreast of these coming changes, and their broader implications, is critical to ensuring a productive and sustainable future.
