On the periodic table, sodium has the same number of outermost electrons and chemical properties as lithium. Elements in the same group also have similar properties. This is an important reason why sodium ions can be as competent as lithium ions as charge carriers.
Sodium is a plentiful mineral resource that is found in crustal abundance at 2.74%, more than 400 times the lithium element, has rich reserves, and is widely distributed since, after all, seawater contains sodium chloride. Moreover, sodium ion battery cathode does not need to use cobalt, nickel, these rare precious metals, the resource is limited by the trouble of a lot less.
With the rapid growth in demand for lithium in electric vehicles, energy storage and other fields, lithium resources are becoming increasingly tight. Sodium salt is much cheaper than lithium salt, and sodium ion batteries can be used without cobalt, nickel and other rare and precious metals, and can also use aluminum foil, which is cheaper than copper foil, as a collector fluid, and the material cost is expected to be 30-40% lower than that of lithium ion batteries.
Since sodium ion batteries work similarly to lithium ion batteries in terms of principle and cell structure, the production line design of lithium can be used to produce sodium ion batteries with minor adjustments.
Sodium ion battery with better stability of aluminum foil as the negative collector, do not have to worry about low voltage resulting in battery performance decay, failure, so you can completely empty the power before transport, to ensure transport safety, but also does not affect the subsequent performance of the battery.
However, because the potential of sodium is higher than lithium, sodium ions are larger and heavier than lithium ions, when embedded in the positive and negative electrode is easy to make a large volume change in the pole piece material, which makes the sodium ion battery in comparison with lithium-ion batteries, there is a low energy density, multiplier performance is poor, short cycle life and other relative disadvantages.
Sodium ion batteries are difficult to mass produce within three years:
1) Industrial process: the current sodium ion battery is equivalent to the lithium ion battery in 2013~2014.
The industry chain is not perfect, the scale effect has not been formed, there is a process of technology maturity, and its price will be more expensive than lithium-ion batteries; material cost considerations, the amount of hard carbon is relatively small and has not yet been scaled up.
(2) Product parameters: the current monomer energy density of 120wh/kg (ceiling can do 200wh/kg). Lithium is the number one metal in the periodic table of elements and is also the lightest metal. This means that, for the same weight, lithium can carry more charge, which means higher energy density.
Lithium batteries are already the optimal solution in terms of chemistry. Sodium batteries are the second-best option, no matter how hard they try. The highest end of sodium batteries to achieve the performance of ordinary lithium iron phosphate batteries, and the actual cost of the former is still higher. Therefore, in the field of power batteries, sodium batteries can not replace lithium batteries.
(3) Application scenarios. Sodium battery energy density (generally less than 120Wh/kg) is significantly lower than lithium iron phosphate batteries (160Wh/kg) and ternary batteries, and the new energy vehicle battery demand match is low, there is no possibility of replacing lithium batteries as the mainstream technology in the power field for the time being. Future applications for energy storage, base stations, low-speed vehicles, low-voltage passenger cars and other markets.
(4) Manufacturing process: and lithium battery manufacturing process is close, the equipment can be used along the lithium battery production line, the battery factory no replacement cost.
(5) safety: thermal runaway temperature is higher than lithium batteries, easy to deactivate (passivization, oxidation).
The current actual production cost of sodium batteries is not a significant advantage. Although the use of relatively cheap metal can reduce the cost of raw materials, but low energy density means more auxiliary materials and manufacturing costs. Standing at the current point in time, we believe that the replacement of sodium batteries for lithium batteries is actually very weak. Considering that sodium reserves are richer than lithium, the strategic significance of sodium batteries as a technology reserve and to ensure energy security should be emphasized, but their commercial value should not be overestimated.