The Chinese battery giant CATL recently introduced an anode-less sodium-ion battery, which may be a more efficient and environmentally friendly alternative to the common lithium-ion batteries
In a way, our lifestyle is made possible by the lithium-ion battery. Even if we only think about our mobile phones, it is not uncommon that one day we will organize our tasks for the rest of the week in the application, we will check Google maps on how to get to the stronghold we wanted, we will correspond with friends, we will write down reminders for ourselves, we will show the people with us an interesting video on YouTube, we will charge the Rab-Ko In the application, we will update on Facebook and Twitter, we will share on Instagram photos we took - and when we get home, we will still have enough battery left to check in the diary what we have planned for tomorrow.
However, the production of the lithium needed for lithium-ion batteries entails significant practical and environmental difficulties, and therefore attempts are currently being made to find a suitable replacement for this battery. One of the prominent alternatives in the field is the sodium-ion battery, which is based on the common element known to us from, among other things, table salt. Recently, the Chinese company CATL - the largest manufacturer of lithium-ion batteries in the world - introduced a new type of sodium-ion battery, which may allow widespread use of the technology.
Lithium-ion batteries have undergone decades of development and improvement since they first came into use, and today they are integrated into a variety of devices that we use in our daily lives - the most prominent of which are cell phones andElectric vehicles. However, lithium production is complex. "Lithium is not uniformly distributed in the earth's crust, so it is relatively easy and cheap to produce only at specific sites," explains Dr. Daniel Mader, a researcher and scientific consultant and one of the founders of the SP Interface company. "Also, 7-4 years Elapses from the moment of discovering a suitable site for the commercial production of lithium until the actual production begins, and a steep increase in the demand for lithium in recent years due to the exponential increase in the production of electric vehicles and battery-based energy storage facilities, in the face of the breaking of the supply chains due to the corona crisis, caused a shortage of lithium in the market. Therefore, today the supply of lithium does not meet the demand, and a bottleneck is created in its supply."
Beyond that, the lithium production process causes to considerable environmental damage, partly because the processes of mining and processing lithium from the ground or water and converting it to a state where it can be used in batteries require a lot of energy.
to produce batteries from waste
One of the leading candidates to replace lithium is also one of the most common elements in nature - sodium, which is well known to us from the salt that seasons our food, and which is found in seawater around the planet. Unlike lithium, sodium can be found in high concentration almost anywhere in the world, and there are simple and cheap methods to produce it. "It is possible to produce sodium on any beach, which will avoid any limitation on the supply chains," says Madar. "In Israel, for example, seawater desalination plants produce brine - water waste with a very high concentration of salts. Instead of discharging the waste into the sea, as is the case today, it will be possible to use it as a source of salt."
The Chinese company CATL, whose batteries are used among other things by Tesla, has invested resources in researching the issue in recent years. CATL's new battery, which the company recently submitted a proposal for registration as a patent, and which will be used in the next generation of sodium-ion batteries it will produce, includes a rigid carbon material with a unique porous structure.
The new development aims to increase the energy density of the battery: the amount of energy per unit of volume or weight - or in simple words, how much electricity the battery will produce until it runs out and needs to be recharged again. According to Prof. Doron Orbach, Head of the Electrochemistry Group at Bar Ilan University, Head of the Center for Energy and Sustainability at Bar Ilan University and Head of the National Research Center for Electric Propulsion, sodium-ion batteries currently have a low energy density compared to rechargeable lithium-ion batteries. However, the new battery is anode-free. "What is meant by batteries without an anode is that instead of a carbon material such as graphite (in a lithium-ion battery) or hard coal (in a sodium-ion battery), where the lithium or sodium ions are stored during the charging process, when charging these new batteries, thin sheets of lithium or sodium will be deposited on copper sheets or Thin aluminum," says Auerbach. "This way we will save the volume and weight that the carbon takes up as the anode - the negative pole of the battery - and we will gain capacity (electrical charge storage, ns), which will allow for a higher energy density."
According to CATL, the energy density of the new battery will be about200 watt-hours per kilogram – Density similar to this of lithium-ion batteries. This is an upgrade of the first sodium-ion battery developed by the company, in July 2021, whose energy density is 160 watt-hours per kilogram. The company will begin commercial production of sodium-ion batteries as early as 2022.
Beyond that, CATL is not alone: so is a company Natron Energy The American and company Altis AB The Swedish announced (separately) the launch of production lines for sodium-ion batteries in 2023.
Adjustments are needed
"Cheap sodium-ion batteries will enable a rapid transition of the electricity grid from relying on fossil fuels to relying on renewable energies and energy storage on a large scale," explains Madar. "Electric vehicles will also become cheaper, and will allow a faster abandonment of gasoline and diesel in favor of electricity. The fact that this is the development of a battery on a large scale by the largest battery company in the world, and not an initial development in a laboratory, guarantees that these batteries will start reaching the market in the near future."
It should be noted that due to the difference in the chemical properties of lithium and sodium, the use of sodium in batteries requires adjustments. "Lithium-ion technologies have a huge advantage: in the production process, they only work with neutral, non-hazardous materials, and in the initial charging process, the lithium ions in these materials are injected into the graphite anode - that is, there is no active lithium in the battery itself, but only the movement of ions, which creates a safe battery And very stable," says Auerbach. "Sodium will not work with graphite in the same way. However, it is possible to replace the graphite with another carbonaceous material, and thus develop a similar technology for sodium-ion batteries as well." Besides graphite, it will be necessary to replace other materials in the battery - the cobalt mixtures, for example, which are used in lithium-ion batteries and which cannot operate in the same way in sodium systems, it will be possible to replace them with other materials - and in the new development iron-manganese-nickel mixtures will be used instead.
The technology keeps getting better
Auerbach clarifies that CATL's new development is not the first time an attempt has been made to develop a battery without an anode. "Theoretically, it is possible to develop such a battery, but due to the instability of this type of system, the number of charging cycles - that is, the number of times the battery can be charged before it goes out of use - may fall below a worthwhile value." The number of cycles is very important when it comes to batteries for solar fields, since in the installation of such a large and complex system, we would like it to operate for a decade or more.
According to CATL, their sodium-ion battery is capable of performing 6,000-3,000 charging cycles (ie, 15-10 years of charging and discharging every day). This is still a lower number of cycles than that of good lithium-ion batteries, which reach 8,000 charging cycles, but it is estimated that within a few years the number will increase to this level. In addition, according to Natron Energy, the battery they produce lasts 50 thousand cycles – 25-5 times a lithium-ion battery.
Either way, Auerbach emphasizes that the field of batteries is constantly evolving. "Lithium-ion batteries are one of the great successes of electrochemistry and materials science nowadays, and scientists all over the world, who are united in hundreds of research groups, are doing systematic work, step by step, and improving this technology in a very reliable way," he says. "It is possible in a similar way to succeed with rechargeable sodium batteries, and to benefit from unlimited energy storage systems in terms of the inventory of the elements that make them up."
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