Date: July 3, 2023.
Imagine an ordinary day with the sun shining high. As the afternoon arrives, you crave the crunchy delight of potato chips. While indulging, you tune into your favorite TV show, but wait, what’s this? Electric vehicle ads left and right!
You can’t help but exclaim, “Man! EVs are all the rage these days!” Curiosity stirs within you and the next thing you know, you are captivated by the incredible advantages: eco-friendliness, cost savings, smooth rides, and futuristic appeal. As the crispness of salty potato chips and the electric buzz of excitement fuse, you discover that they share something in common: Sodium!
Sodium chloride (salt) adds flavor to your chips while sodium ions store energy in your EV’s battery.
Wait…Ms. Author, aren’t lithium batteries running our EVs and other electronic devices?
Yes, that’s precisely right! However, believe it or not, we are in a lithium crunch!
Let me shed light on why lithium has dominated the industry since the 1990s.
Firstly, lithium is the third lightest element! Making it ideal for portable electronic devices where weight is a crucial factor. Second, these batteries can store a lot of energy (higher energy density) for their size, so they last longer and provide more power. They also have a higher operating voltage, which means they use electrical energy efficiently. Moreover, they don’t lose their charge quickly when not in use (low self-discharge rate), so they are good for devices that are not used all the time or need to be stored for a long time. They can be recharged at any time without losing much capacity (minimal memory effect). Additionally, they can be charged and discharged many times before they start losing their ability to hold a charge. Lastly, they can be recharged quickly compared to other types of batteries.
Why are we in a lithium crunch?
Lithium-based batteries have gained immense popularity due to their remarkable advantages. The rise of electric vehicles and portable electronics has further fueled the demand for these batteries. Additionally, the shift towards renewable energy sources has increased the need for energy storage systems utilizing lithium-ion batteries. However, the production of lithium is constrained by the availability of viable lithium deposits, making it challenging to meet the growing demand. This has resulted in a supply-demand imbalance. Regarding lithium recycling, it is not a straightforward solution due to the high costs associated with the technology involved.
Now let’s introduce the rising star- Sodium-based batteries (SIBs).
It is essential to understand -
why sodium batteries are outperforming lithium batteries?
Before diving into the details- Firstly, sodium is more abundant and widely available, alleviating concerns about resource scarcity and cost. Secondly, sodium-based batteries can be produced at a lower cost, making them a cost-effective choice for large-scale energy storage applications. Additionally, sodium-based batteries offer enhanced safety as sodium is less reactive and volatile than lithium, reducing the risk of accidents (Lithium-based batteries are susceptible to thermal runaway, which is a rapid and uncontrolled increase in temperature that can lead to fires or explosions). In terms of environmental impact, sodium-based batteries have a smaller footprint as sodium is more easily recyclable and requires less resource extraction than lithium (the mining and processing of lithium can have negative environmental effects, including habitat disruption, water pollution, and carbon emissions). Lastly, sodium-based batteries have the potential for scalability in energy storage systems due to sodium’s abundant and cost-effective nature.
Key Components of SIBs-
Every battery has important parts like the anode, cathode, electrolyte, and separator.
In SIBs, we can’t use the same stuff as LIBs for the anode because sodium ions (Na+) are bigger than lithium ions. So, they use hard carbon (HC) for the anode. HC is pretty cool because it’s easy to make, stable, and works well with sodium ions. The cathodes in SIBs are usually made of different materials like oxides, phosphates, or something called Prussian blue analogs (PBAs). These materials help the battery store and release energy. Now, let’s talk about the electrolyte. It’s like the battery’s juice that helps the ions move around. SIBs have two types of electrolytes: one is aqueous and safe, but it has some limitations. The other type is organic-based, which means it’s made from special chemicals and is currently used with sodium salt dissolved in organic solvents. Last but not least, we have a separator. It’s like a barrier that keeps the anode and cathode separate but allows sodium ions to move around. They use glass microfibers or fancy-sounding stuff called polypropylene/polyethylene as separators.
Challenges faced by SIBs- Sodium batteries have lower energy densities than lithium batteries so they can store less energy for their size or weight, which means they might not be as good for things like electric cars that need a lot of power. Another challenge is that the larger size of sodium ions can make batteries less stable over time. Repeated charging and discharging of sodium ions can damage the battery structure, affecting its performance. Lastly, scientists are still working on finding the right materials for sodium batteries that can hold a lot of energy, last a long time, and be affordable to make. This is crucial to make SIBs a practical option for everyday use.
Emerging technologies to address SIB challenges:
1. Organic materials-based anodes: In regular batteries, the part that stores energy (the anode) is usually made of graphite, but it doesn’t work well for sodium-ion batteries. Instead, scientists are looking at using organic materials like molecules with azo, carboxylates, and amine groups. They have found that these organic materials can store more energy from sodium ions at lower voltages. They are also exploring special materials called metal-organic frameworks (MOF) and covalent-organic frameworks (COF) that have flexible structures and lots of tiny spaces. These materials can be designed specifically for different battery types and have shown promising results in various applications.
2. Na-compensation additives: When a battery is used for the first time, some sodium ions are consumed and cannot be reused, which affects the capacity. Scientists have been researching additives that compensate for lost sodium ions. For example, sodium biphenyl (Na-Bp) is used as an additive in some batteries to provide extra sodium ions. Other additives like sodium carbonate and sodium fluoride can improve the battery’s stability and its materials.
3. Solid-state SBBs: Traditional batteries use liquid electrolytes, which can be flammable and unsafe. Solid-state batteries (SSBs) are safer because they utilize solid electrolytes. One type of solid electrolyte called NZSP has been used with a cathode material called NVP. They have shown good capacity and stability.
4. Cationic and anionic redox chemistry for cathodes: The cathode is another key part of the battery that stores energy. Scientists have found that using both cation and anion redox reactions in the cathode can increase its capacity. Combining these two types of reactions, they can improve the cathode material’s performance and stability.
Let’s spark a battery revolution together!
The future of energy storage is bright, and it’s going to take a collective effort to propel sodium-ion batteries (SIBs) into the spotlight. Imagine a world where sodium-powered devices and vehicles are the norm, where we bid farewell to range anxiety and embrace a sodium-fueled future. So, dear reader, let’s join forces and ignite the spark of collaboration! Let’s charge ahead and make sodium the coolest element on the periodic table!
Author’s note: How do you envision yourself rocking the SIB revolution and bringing a dash of fun and sustainability to the battery industry?
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