Several auto manufacturer, battery technology developers and startups are working on new battery technologies that are more efficient, offers a longer range and have higher power density compared to conventional batteries. While conventional and widely-used lithium-ion batteries are playing a vital role in the development of electric vehicles, they are very expensive to produce and unstable in high temperatures.
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As the researchers and battery manufacturers are searching for more sustainable replacement materials for lithium, one alternative is making quite a buzz - sodium. In the periodic table, lithium and sodium are neighbours, which means they offer similar properties and can both be used for battery cell manufacturing.
Sodium-ion batteries can offer some crucial advantages to EV manufacturers and consumers - sustainability, affordability, and increased safety. However, the energy density in sodium-ion batteries is lower than lithium-ion counterparts. Though this issue is likely to be improved over the next few years with constantly improving technologies.
This is why several battery manufacturers are exploring the possibility to use sodium-ion batteries in the upcoming electric vehicles, in place of the traditional lithium-ion batteries. Here are three key reasons why sodium-ion batteries can become a suitable alternative to lithium-ion batteries.
Advantages of sodium batteries
The electrode material used in sodium-ion batteries is mainly sodium salt, which is more abundant and cheaper than lithium. Since sodium-ions are larger than lithium-ions, sodium-ion batteries are a cost-effective alternative when weight and energy density are not high requirements. Compared with lithium-ion batteries, sodium-ion batteries have the following advantages:
The sodium salt raw material reserves are abundant and the price is low. Compared with the ternary cathode material of lithium-ion battery, the iron-manganese-nickel-based cathode material is used, and the raw material cost is reduced by half;
Due to the characteristics of sodium salt, it is allowed to use low-concentration electrolyte (with the same concentration of electrolyte, the conductivity of sodium salt is about 20% higher than that of lithium electrolyte) to reduce costs;
sodium-ions do not form an alloy with aluminum, and aluminum foil can be used as the current collector for the negative electrode, which can further reduce the cost by about 8% and reduce the weight by about 10%;
Since the sodium-ion battery has no over-discharge characteristics, the sodium-ion battery is allowed to discharge to zero volts. The energy density of sodium-ion batteries is greater than 100Wh/kg, which is comparable to lithium iron phosphate batteries, but its cost advantage is obvious, and it is expected to replace traditional lead-acid batteries in large-scale energy storage.
At present, one of the main cost sources of new energy vehicles is the battery. The several advantages of sodium-ion batteries are related to cost. It can be seen that it is expected to reduce the overall cost of new energy vehicles in the future, but its disadvantages are also very obvious: low energy density
Energy density: sodium battery vs lithium battery
In terms of the volume and mass of sodium-ions and lithium-ions, under the same weight, the volume of sodium is more than three times that of lithium, that is to say, the diameter of sodium-ions is larger and the energy density is much lower than that of lithium batteries.
From the data we have seen on the Internet, the energy density of current sodium-ion batteries is about 80~100Wh/kg. In 2017, a 150Wh/kg sodium-ion battery was developed. Recently, various space compression schemes have been used, and the hybrid design of series and parallel integration of sodium and lithium batteries for new energy vehicle schemes has successfully rescued the energy density of the battery to about 160Wh/kg. To be honest, it can be compared with phosphoric acid. Lithium iron phosphate battery (LiFePO4) is comparable and is expected to replace the lead-acid battery market in the field of energy storage.
Nevertheless, lithium-ion batteries can have a higher energy density than sodium-ion batteries and are smaller and lighter. This is where sodium batteries are inherently inferior to lithium batteries.
It’s fascinating to see the advancements in battery technology, especially with the shift towards more sustainable options like sodium-ion batteries. I recently stumbled upon PKnergy take on lithium-ion battery packs, and it got me thinking about the potential of sodium-ion batteries. Sure, they might have lower energy density now, but with ongoing advancements, who knows what the future holds? It’s exciting to witness the possibilities for more sustainable and affordable electric vehicles.
Itakua mbali before they become practical for day to day electronics use i.e phones, laptops
lithium-ion is still lighter and stores more energy. but lets hope they succeed this will make sodium-ion batteries cheaper hence solar will be available for everyone
