Lithium-sulfur battery is a type of lithium battery that has not yet been fully put into practice.
Lithium sulfur battery is a lithium battery that uses sulfur element as the positive electrode and lithium metal as the negative electrode. Many of its characteristics are better than those of lithium batteries widely used today. , due to the difficulty of their practical application, they are currently used very little.
The main obstacles of lithium-sulfur batteries have been overcome
Lithium-sulfur batterieshave a fatal flaw, it that is, poor stability and poor performance after use. It degrades quickly and cannot complete the normal charge-use-discharge-charge cycle. The reason for this defect is that lithium polysulfide Li2Sx is produced when using lithium-sulfur batteries. This compound cannotefficiently perform charge and discharge cycles, making lithium-sulfur batteries currently unmarketable.
Lithium sulfur battery is a type of lithium battery. Lithium sulfur battery is a lithium battery with sulfur element as the positive electrode and lithium metal as the negative electrode. Elemental sulfur is abundant in the earth and has the characteristics of low price and environmental friendliness.
The main problems existing in lithium-sulfur batteries are:
First, the electronic conductivity and ionic conductivity of elemental sulfur are poor, and the conductivity of sulfur materials at room temperature is extremely small (5.0×10-30S cm-1), the final reaction products, Li2S2 and Li2S, are also electronic insulators, which is not conducive to the high-rate performance of the battery< /p>
Secondment, the intermediate discharge products of the lithium-sulfur battery dissolve in the organic electrolyte. In liquid, this increases the viscosity of the electrolyte and reduces ionic conductivity. Polysulfide ions can migrate between positive and negative electrodes, resulting in loss of active materials and wasted electrical energy. (Shuttle effect). The dissolved polysulfides will diffuse through the separator to the negative electrode, react with the negative electrode, and destroy the solid electrolyte interface film (SEI film) of the negative electrode.
Third, the final discharge product of the lithium-sulfur battery, Li2Sn (n=1~2), is electronically isolated and insoluble in the electrolyte, and is deposited on the surface of the conductive part of the skeleton; lithium sulfide detaches from the conductive skeleton and cannot be reversed. During the charging process, the battery reacts with sulfur orhigher order polysulfides, causing a sharp decrease in capacity.
Lithium-sulfur solid-state battery test passed? Where will ternary lithium batteries go?
With the continued development of electric vehicles, new energy vehicles have attracted the attention of consumers. Scientists see great potential in lithium-sulfur batteries, which work differently from lithium-ion batteries. This is a more environmentally friendly method of driving because it does not require expensive, hard-to-obtain raw materials like cobalt. However, stability and other issues have hampered the development of this technology so far.
In order to promote the continued development of new energy vehicles, American engineers continue to conduct research on these researches and have made revolutionary progress in these researches. According tos American foreign media, American scientists used a rare chemical substance called sulfur to prevent destructive chemical reactions in electric batteries, making lithium-sulfur batteries more accessible. Close to commercial use. The research results were published in the journal Communications Chemistry.
Compared with traditional ternary lithium batteries and lithium iron manganate batteries, lithium sulfur batteries are more promising in terms of storage. This is not only due to the abundant reserves of sulfur, but also cobalt and cobalt. used in current batteries Compared to nickel, the sulfur source does not pose a problem for manganese. At the same time, lithium-sulfur batteries can also bring another significant improvement in performance, and their storage potential is several times that of lithium-sulfur batteries.are lithium.
But in fact, lithium-sulfur batteries also encounter some problems during the production process, which have troubled many researchers, namely the formation of polysulfides. When lithium-sulfur batteries operate, these substances enter the electrolyte and undergo chemical reactions. This reaction can damage the capacity, lifespan and health of the battery.
To overcome this problem, scientists replaced the carbonate electrolyte with an ether electrolyte that does not react with polysulfides. But this creates other problems, because the ether electrolyte itself is very volatile and contains low boiling point components, meaning the battery can quickly fail or melt if heated above of the ambient temperature.
According to foreign media, this sulfur chemistry can only be observed at high temperatures in the laboratoryor in oil wells in nature. After a year of testing and 4,000 charge and discharge cycles. Scientists have shown that this lithium-sulfur battery can last up to more than 10 years of regular use. The team believes the battery, which has three times the capacity of lithium-ion batteries, paves the way for greener batteries that would allow electric vehicles to travel further per charge.
At present, the battery mainly used in pure electric vehicles is ternary lithium battery, and some models use lithium iron phosphate battery. Both of these batteries are liquid batteries, so internal chemical reactions are inhibited in low temperature conditions, which will affect battery life. This was also criticized by consumers. In order to remedy this situation, many automobile manufacturersare currently beginning to develop solid-state batteries. According to relevant media reports, British lithium-sulfur battery technology company OXIS Energy successfully tested a battery cell sample with an energy density of 471 Wh/kg. So what does the successful testing of solid-state lithium-sulfur batteries mean?
As mentioned above, in order to alleviate the "cold cooling" phenomenon of liquid batteries, many automobile manufacturers have begun to develop solid-state batteries. Solid-state batteries use solid electrolytes, have a wider operating temperature range, are more stable and have a higher energy density than liquid batteries, providing a longer cruising range. However, the production cost of solid-state batteries is also high, and the charging speed is relatively slow. In terms of coproduction costs, if you use existing technology to make a solid-state battery sufficient to power a smartphone, the cost will reach $15,000, and the cost of a solid-state battery sufficient to power a car is even more pupil. upper.
The lithium-sulfur battery tested by the British company is a lithium battery with sulfur as the positive electrode and lithium metal as the negative electrode. The theoretical specific capacity of this battery and the theoretical specific energy. of the battery reach 1675 mAh/g and 2600 Wh/kg respectively. evenCompared with other solid-state batteries, the production cost of lithium-sulfur solid-state batteries is relatively low and the energy density is high. Therefore, the successful testing of this battery can provide new research directions to alleviate the problem of high solids content. state ofs battery production costs and enable the application of solid-state batteries. The possibilities are considerably increased.
Of course, although the production cost of solid-state lithium-sulfur batteries is lower than that of other solid-state batteries, they have the problem of longer life. short. Therefore, there is still a long way to go. before solid-state batteries can actually be used.
This article is from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.