Acculon Energy

Exploring Sodium-Ion: A Promising Alternative Cell Chemistry

Come along as we delve into the realm of battery cell chemistry, where we will explore the potential of sodium-ion, compare it with lithium-ion, and examine the factors that have kept it from taking center stage in the electrification world so far.

Contact: Betsy Barry
Communication Manager

In the ever-evolving landscape of energy storage, the heart of innovation pulses with the selection of the right cell chemistry. While lithium-ion batteries have dominated the electrification movement, powering everything from pocket-sized devices to interstellar crafts, there’s a new contender stirring up excitement: sodium-ion (Na-ion) technology. But the road to its widespread adoption has been far from straightforward.

In the initial stages of designing an electric battery module or pack for mobility and industrial applications, selecting cell chemistry plays a crucial role. Cell chemistry dictates energy and power density, safety, lifespan, thermal behavior, system and lifecycle costs, etc. Pretty much everything! At the same time, no solution meets all the requirements. So it’s always a balance of what can be done by a battery pack vs. cost, weight, volume, lifetime, safety, and power capabilities.

In the 21st century, lithium-ion chemistries tend to win more and more design decisions and now can be found anywhere from our pocket devices to space and ocean crafts. However, researchers and engineers are exploring alternative cell technologies to overcome some of the limitations associated with Li-ion batteries. One such emerging technology is sodium-ion (Na-ion) cells.

Conversations surrounding Na-ion are growing in the electrification landscape; however, their emergence in the EV market, while highly anticipated, has stalled over time. Even though most cell manufacturing companies developing Na-ion over the past decade have made significant progress, these cells have yet to scale to the point where they are a viable alternative to Li-ion. What factors are inhibiting the broader adoption of this cell technology so far?

In the Na-ion space, various companies are actively working towards commercializing three primary types of cathode active materials: oxides, polyanion-type, and hexacyanometalates. Each of these material types has specific pros and cons, but all of them have the potential to create high-performing sodium-ion batteries, and it seems that the oxide-based materials winning the race. Meanwhile, only a type of anode-active material, amorphous carbon, is commonly used in high-energy sodium ion cells. So, the winning active materials chemistry combinations seem to be identified in the industrialization landscape.

Best combinations of active materials proved to get access to sodium-ion batteries that are almost on par with LFP lithium-ion chemistry in terms of gravimetric energy density and just slightly beyond in terms of volumetric energy density. So while many demanding mobility applications will not be covered with sodium-ion batteries, industrial, stationary, and non-demanding mobility may choose sodium ion if other metrics beyond energy density will be fine.

It is interesting to note that usually, sodium-ion developers cycling data include fast charging and fast discharging cycling even though, generally, fast charging shortens cells’ life. Enhancing the lifetime and overall durability of sodium-ion batteries is essential to meet the demands of long-lasting and reliable energy storage systems. As soon as energy storage systems manufacturers get verified performance data on the sodium ion cells that meet the needs of real systems, the implementation of sodium ion chemistry will start immediately.

Based on ongoing research conducted here at Acculon Energy, sodium-ion battery cells are showing promising results in terms of durability.

Along with sodium being readily abundant & available, this new technology could become a viable alternative to lithium-ion battery cells for a wide range of uses.   

Here at Acculon Energy, we have been conducting our own research into Na-ion cells that are entering the market. The results so far are promising. On one of the high-energy Na-ion cell types, we are now about the 300th cycle of 0.5C rate cycling at room temperature with full depth of discharge and getting 96.3% of maximum capacity.

Fig. 1.  Capacity degradation of a Na-Ion cell at 0.5C/0.5C cycling at room temperature.

Based on the linear degradation trend, the 80% capacity limit is projected to be reached after about 1650 cycles. This impressive level of durability, if achieved, could open a door to numerous diverse applications.

Another aspect of Na-ion batteries that makes them an attractive alternative is that sodium is more readily available and abundant than lithium, and the availability of electrode materials for sodium-ion batteries is generally better than for lithium-ion batteries. Therefore, supply chain issues are less of a concern for sodium-ion chemistry than lithium-ion.

Currently, the manufacturing infrastructure, supply chains, and production processes for Na-ion batteries are not as mature as Li-ion, which leads to higher manufacturing costs. Scaling up production and optimizing manufacturing processes to reduce costs are necessary for sodium-ion batteries to become economically competitive.

Looking to the future of electrification, a range of industrial markets, like construction, will continue to gain momentum, driving the need for advanced energy storage solutions. In response to this growing demand, research and development efforts in the field of battery technology are expected to accelerate, focusing on innovation, efficiency, and sustainability. 

Engineers and scientists at Acculon Energy and other organizations driving electrification will strive to enhance the performance and safety of existing lithium-ion batteries while exploring emerging technologies such as sodium-ion, solid-state, and different novel cell chemistries. Continued advancements in materials science, manufacturing processes, and battery management systems will pave the way for breakthroughs in energy density, faster charging capabilities, extended cycle life, and increased affordability. Acculon’s continued pursuit of progress in battery technology will play a pivotal role in unlocking the full potential of electrification across industries, contributing to a cleaner, more sustainable future.