The expected growth in the battery market and the existing challenges in conventional technologies are causing large manufacturers to start evaluating complementary or alternative chemistries to lithium, such as sodium, sulfur, aluminum or potassium. 

The main goal is to overcome the potential challenges that an excess demand could cause in the supply chain. In this way, the aim is to complement current technologies with new solutions that can provide a similar response to lithium batteries, thus reducing dependence on this material. 

But at the same time, some large manufacturers are also beginning to see the possibility that some of these bets could take batteries to a new scenario, surpassing the current performance of conventional lithium-ion technologies as well as the challenges presented by their manufacturing process (especially related to obtaining raw materials). 

To this end, announcements and developments are beginning to emerge that combine new materials with lithium or even replace it entirely.

Sodium begins to gain popularity 

In this context, one of the most popular potential alternatives in recent months has been sodium-ion batteries, especially after the announcement of the giant CATL (Tesla´s primary battery supplier). Last July, the Chinese company presented the first generation of sodium-ion batteries, announcing its intention to start industrializing this technology on a large scale from 2023, combining it with the lithium-based solutions and designed to be used in mobility applications and, above all, stationary applications.

As great strengths, sodium-ion batteries present fast-charging capacity, lower cost and greater sustainability, key features for uses such as electric vehicles or the electric grid. However, there are still two major areas for improvement in which work will continue in the coming years. Especially the energy density, which means a lower autonomy of these batteries compared to lithium-ion batteries. Thus, while, on average, a lithium-ion battery can have an energy density of around 250 Wh/kg on average, the current state of the art of sodium-ion batteries places this indicator at around 150-160 Wh/kg. 

CATL itself has already announced that the second generation of sodium-ion batteries will have a density of around 200 Wh/kg, which shows that there is still room for improvement in this regard.

This alternative is not new in the market, as entities such as Faradion, Natron Energy, Tiamat or CIC energiGUNE itself have been working with it for years due to its potential. But CATL´s announcement indeed demonstrates the commitment that the industry can begin to make to this technology. Hence, some experts see it as a strong candidate to complement or even partially replace lithium-ion batteries. It is expected that by 2030, the value of the sodium-ion battery market could exceed 4 billion euros worldwide:

Sulfur as a lithium partner

But in this race to develop new technologies, not all the alternatives involve completely replacing the almost omnipresent lithium. 

This is the case of other major technologies that have been gaining weight in recent years: lithium-sulfur batteries.

This solution, which combines a lithium anode with a sulfur cathode, stands out for its high gravimetric energy density thanks to the high theoretical capacity of the active material. 

In addition, other strengths of this alternative are the potential ease of industrialization, since sulfur is a more abundant and cheaper material than lithium; the lower toxicity, which makes it more environmentally friendly; and the lightness, which makes it an excellent option for future use in mobility applications (mainly heavy-duty as well as other means such as electric cars, aviation or navigation).

However, two major areas of improvement in this technology have prevented its emergence in the industry. On the one hand, the sulfur cathode´s high degradation which leads to a very limited useful life. On the other hand, its low volumetric density, which for now restricts its use in applications where space may be limited. 

The improvement of these indicators are the two great challenges on which the industry and centers such as CIC energiGUNE itself are currently working, intending to take the definitive step in developing and popularizing this alternative.

Aluminum, potassium, calcium... other solutions being considered by the industry 


Sodium-sulfur batteries are the ones that have stood out the most recently due to the advances and announcements made in the market. However, they are not the only alternatives in which the industry is getting into to develop new technologies and solutions.

In this sense, we find a wide variety of elements being studied for use in the battery sector.

Such is the case with aluminum, one of the most abundant materials on earth. This fact (which reduces the cost of batteries), together with a high power density (which implies a higher charging speed) and an increase in useful life, leads some companies to work on this alternative. 

For example, the Australian company GMG is working on the development and industrialization of a new type of aluminum-ion and graphene batteries.  

However, as with other alternatives mentioned, energy density is the major handicap of these batteries, as they do not exceed 160 Wh/kg.

Another element that is being analyzed is potassium, although its development and research are much more embryonic. Again, one of its significant advantages is being abundant (which reduces its cost) as well as its longer useful life

However, as with sodium, the higher atomic weight and, therefore, lower capacity and performance during the charging and discharging process are the great areas of improvement that need to be worked on to make this solution a real alternative in the future. 

Calcium, zinc, magnesium... are other elements that have been or are being considered for adding to or replacing lithium batteries. The aim of all this is to achieve new solutions that will reduce dependence on lithium and even improve the performance of lithium batteries.

It will be interesting to see how all these research lines develop since it will depend on them and their results to meet the expected demand in the battery market, as well as the sustainability objectives that will determine the future of the industry.  


Nuria Gisbert, Director General of CIC energiGUNE; Member of the Expert Committee of the Basque Parliament on the Basque Energy Agreement, member of the scientific advisory committee of the Vitoria-Gasteiz Green Deal and member of the Scientific Advisory Committee of the Basque Council for Science, Technology and Innovation of the Basque Country.


In collaboration with:

Iñigo Careaga: BCARE Business Analyst

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