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Engineering Sustainability Technical Technology

High-Sodium Diet?

Looks like sodium-ion battery development is moving quite quickly. In addition to the announcement by Northvolt last week, several Chinese companies are also involved in the development, production, and use of sodium-ion battery products.Seems rather ironic since the original article I saw touted a reduction of supply dependency on China (which is a big producer of lithium-ion batteries) due to use of sodium-ion technology.

Sodium-ion battery chemistry provides lower energy density compared to lithium-ion battery chemistry. This means that for the same quantity of stored energy a sodium-ion battery will be larger/heavier than a lithium-ion battery. However, sodium-ion technology also costs less than lithium-ion technology. This makes a sodium-ion chemistry more attractive for energy storage applications where lower cost is a higher priority than size and weight constraints. An example of such an application would be supplemental energy storage for the power grid.

Battery size and weight are relatively more important for electric vehicles. So lithium-ion technology is likely to persist for vehicular applications. For vehicles where a smaller quantity of stored energy (which translates to a shorter range of travel) is acceptable, sodium-ion technology may still be useful. Chery, a Chinese car maker, has said that it will use CATL’s sodium-ion batteries to power its shorter-range vehicles. China-based CATL is reputedly the world’s largest manufacturer of battery cells for electric vehicles.

Categories
Engineering Sustainability Technology

Breakthrough battery?

A Swedish company has announced a lithium-free sodium-ion battery that is supposed to be cheaper and more sustainable. It has an energy density of 160 Wh/kg.

It will require more development before becoming commercially competitive. Energy density and cost considerations vary from application to application so this sodium-ion battery development is still a good step forward.

Lithium-ion battery densities have improved enormously in the last decade, see this article. (Note, the bar chart shows volumetric energy density, Wh/l, and not mass energy density Wh/kg).

In early 2023 a record of just over 700 Wh/kg (1650 Wh/l) was set for Li-ion batteries. A comparison of energy densities for various battery chemistries is shown here. A history of Li-ion batteries can be found here.