[Bojo, Battery] Sodium and Magnesium Batteries Instead of Lithium? Why It's Still Hard to Change the Market

by Jeong Donghoon

Published 04 Jul.2023 09:02(KST)

Updated 07 Aug.2023 15:47(KST)

Editor's Note'Bojo, Battery' is a series that takes a closer look at the battery industry, which has emerged as the center of next-generation advanced industries. It examines the agile movements, strategies, and conflicts among governments and companies worldwide vying to dominate the battery manufacturing ecosystem. We will also cover the technological competition to create safer and longer-lasting batteries. We aim to serve as an 'assistant' to help readers and investors better understand the battery industry. We will share battery stories that are easy to approach.

[Bojo, Battery] Sodium and Magnesium Batteries Instead of Lithium? Why It's Still Hard to Change the Market

The commercialization movement of sodium and magnesium ion batteries, which can be produced more cheaply than lithium-ion batteries, is accelerating. However, there are clear technical limitations that prevent these from overturning the battery industry landscape.

China's CATL, the world's largest battery company, recently announced plans to equip electric vehicles with the sodium batteries they developed. These batteries will be installed in models such as the 'iCAR 03' electric vehicle from Chinese automaker Chery Automobile. The energy density and price of CATL's sodium battery are both reported to be about 40% of those of lithium-ion batteries. It can be charged to 80% in just 15 minutes at room temperature and maintains over 90% performance even at minus 20 degrees Celsius.

Sodium-ion batteries use sodium instead of lithium, making them cheaper. However, they have been criticized for lower efficiency due to relatively low energy density. Sodium reserves are 1,000 times greater than lithium, and the selling price is about one-thirtieth that of lithium. Considering global mineral resource limitations and prices, there is analysis suggesting a high potential for the commercialization of sodium-ion batteries in the future. The production volume of sodium batteries in China is expected to increase from 3 GWh this year to 347 GWh by 2030, with an estimated average annual growth rate of 97% (according to China EVTank data).

Research and development of magnesium batteries are also active, centered in Europe. The University of Cambridge in the UK, along with universities and research institutions in Denmark, Israel, and Germany, are jointly developing magnesium-ion batteries. Magnesium is a material with an energy density exceeding 1,000 Wh per liter, more than twice that of lithium batteries. Magnesium is also cheaper and more abundant than existing key battery materials like lithium and cobalt, which some countries depend on for supply. Unlike sodium, which has lower energy density than lithium, magnesium boasts about 1.9 times the capacity of lithium metal, which is considered an advantage.

There are also criticisms that these efforts are merely attempts to 'turn the tables' in a battery market dominated by lithium-ion batteries. Sodium has a larger atomic radius than lithium, resulting in significantly lower energy density. Due to its density being even lower than that of LFP (lithium iron phosphate) batteries, some argue it is unsuitable for electric vehicle batteries. While commercialization may occur this year, the prevailing view is that sodium batteries will compete with mid-to-low-priced LFP batteries rather than NCM (nickel-cobalt-manganese) ternary batteries. Professor Jae-Pil Cho, Distinguished Professor of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology, said, "(Sodium batteries) require verification of fire safety," adding, "During overcharging, lithium or sodium can precipitate on the anode surface (solid formation in liquid), and if an unexpected short circuit follows, it can lead to an explosion. If the explosive force of sodium is several times that of lithium, sodium batteries could be more dangerous."

Magnesium batteries must overcome the 'dendrite' phenomenon. Dendrites are branch-like crystals that accumulate on the metal anode surface during battery charging. The formation and growth of dendrites degrade battery performance. Moreover, if dendrites continue to grow and reach the opposite electrode (cathode), they can cause fires, making it crucial to suppress this phenomenon.

An industry insider said, "The price reduction competition in electric vehicles triggered by Tesla has also spurred active research into low-cost materials in the battery industry," but added, "However, battery technology closely related to safety is difficult to advance rapidly. It is expected to be challenging to stabilize in a short period."