The pros and cons of lithium-sulfur batteries for new energy vehicles

The low energy density and high cost of power batteries for new energy vehicles have always troubled new energy vehicle manufacturers at home and abroad. In order to solve this problem, power battery manufacturers have recently begun to develop high-energy batteries with low production costs. At present, some companies have launched high-energy battery samples such as metal (aluminum, zinc, etc.) air batteries and lithium-sulfur batteries, which brings hope to the new energy vehicle industry to break through the technical bottleneck of power batteries. If Zhongju Leitian's lithium-sulfur batteries can be put on the market in large quantities in 2012, the time for the industrialization of domestic electric vehicles is likely to be greatly advanced.

Lithium-sulfur batteries are highly anticipated by relevant parties because they have many obvious advantages over the mainstream lithium iron phosphate batteries in the current market. First of all, in theory, the energy density of lithium-sulfur batteries far exceeds that of most types of power batteries. According to the data from the "2010-2015 China Electric Vehicle Industry Investment Analysis and Prospect Forecast Report" recently released by CITIC Consulting, although there is still some debate in the industry about the highest energy density of lithium-sulfur batteries, it is certain that its maximum energy density will not be less than 1,000 watt-hours/kilogram in theory, while the energy density of lithium iron phosphate batteries currently produced in China is mostly below 100 watt-hours/kilogram, and there is not much room for improvement. Obviously, from the perspective of energy storage efficiency alone, lithium-sulfur batteries are more suitable as automotive power batteries.

In addition to its very high energy density, lithium-sulfur batteries also have some other advantages. On the one hand, their production cost is relatively low. Since lithium-sulfur batteries mainly use sulfur and lithium as production raw materials, the production cost is relatively low; on the other hand, lithium-sulfur batteries are low in toxicity after use, and the energy consumption of recycling is relatively low.

Although lithium-sulfur batteries have obvious advantages over many types of power batteries, they also have some shortcomings. The biggest disadvantage of lithium-sulfur batteries at present is that they have a relatively low number of recycling times. Because the vulcanized polymer has the characteristics of relatively poor stability, the current number of recycling times of lithium-sulfur batteries is much lower than that of ordinary lithium iron phosphate batteries, which greatly increases the cost of using lithium-sulfur batteries. It can be said that as long as this performance disadvantage of lithium-sulfur batteries cannot be changed, it will be difficult to promote their use on a large scale.

Although the performance of lithium-sulfur batteries is very advanced in theory, it is very difficult to turn theory into a practical product. The United States plans to increase the energy density of lithium-sulfur batteries to 500Wh/kg in 2013, while Japan, a world powerhouse in power battery technology, plans to achieve the above goal in 2020. This reflects from one aspect that the research and development of lithium-sulfur batteries is very difficult, and developed countries still have great differences on when to overcome some technical bottlenecks of lithium-sulfur batteries.