The global car industry is struggling to keep up with a growing demand for electric vehicles (EV), due to shortages of critical components and materials.
One of these components is lithium – a key material used to make the batteries that power most EVs and many electronic devices, including smartphones and laptops.
Lithium-ion batteries have become the standard in EV design, with car manufacturers like Tesla experimenting with different battery designs to produce more power, increase maximum ranges, and decrease charging times.
This soaring demand for EVs and other electronic goods, combined with global supply and production issues as a result of the pandemic and recent geopolitical events, have led to lithium prices increasing fivefold over the last year, according to Bloomberg.
Investment bank Morgan Stanley stated that electric cars prices could go up by as much as 25% as a result.
Fortunately, there may be an alternative: sodium.
Sodium and lithium are both alkali metals that share a lot of properties, and sodium-ion batteries have a few distinct advantages over their lithium counterparts.
Lithium is a rare resource that is concentrated in a few regions around the world – such as the US, China, and Ukraine.
As the New York Times pointed out, this is a reason why the ongoing conflict in Ukraine has contributed to rising lithium prices.
Sodium, in contrast, is one of the world’s most common elements and is distributed far more evenly across the globe.
The availability of sodium means global supply is far less likely to be affected by geopolitical events in specific regions.
Sodium’s abundance has the added benefit of making it a cheaper material than lithium.
While the cheaper cost of sodium is not currently reflected in most batteries, largely due to the industry’s prioritization of lithium, prices are expected to improve in the years to come – and the price comparison between sodium and lithium batteries will only become more favourable as lithium prices are expected to continue to rise.
Not only is sodium itself a cheaper and more abundant element, it can also be used in combination with other cheaper elements such as iron and manganese, reported CNBC.
The high cost of lithium-ion batteries is partly due to their use of cobalt, another rare element only found in high concentrations in a handful of countries, such as the DRC, which is estimated to contain over half the world’s cobalt supply.
Safety and longevity
Another big concern with lithium-ion batteries is the risk of fires.
Lithium batteries can become unstable when placed in extremely cold or hot conditions.
EV batteries also run the risk of thermal runaway, where the heat from damaged cells can affect adjacent cells – leading to a chain-reaction electrical fire that is difficult to put out.
While not immune to the risks associated with other batteries, sodium batteries are far more stable at extreme temperatures, lowering the risk of fires.
Another benefit of sodium’s relative stability is that batteries may also have a longer life span, being able to survive more charge cycles.
This is according to Korean and US-Chinese studies that ran roughly 500 charge cycles on sodium-ion batteries to see how their capacity held up.
The biggest drawback of sodium is that it has a lower energy density than lithium.
One of the main reasons lithium was adopted as the current standard for EV battery design is its high energy density – which is crucial to improving the range and performance of cars.
Another downside is that sodium is roughly three-times heavier than lithium, which is significant given that a lithium battery in an electric car makes up a large part of the vehicle’s weight.
For example: the battery in a Tesla Model S weighs just under 550kg.
Where the technology currently stands
In countries like India and Taiwan, battery-swapping for electric scooters and rickshaws has become popular in recent years, which presents an opportunity for sodium-ion batteries.
The smaller range and power requirements of these vehicles means that the lower energy density of sodium batteries is a non-issue – and the technology could see improved adoption.
India is even anticipating making an industry switch from lithium to sodium batteries, according to Bloomberg.
As the technology sees more interest, investment, and adoption, sodium-ion batteries may be able to grow their presence in the EV market.