The hottest lithium sulfur battery may replace ter

2022-08-02
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Lithium sulfur batteries may replace ternary lithium batteries to become a new momentum in the future lithium battery field

at present, the global new energy vehicle market has entered a critical period of vigorous development, so the lithium battery industry chain is rapidly maturing. In March 2017, the Ministry of industry and information technology and other four ministries and commissions jointly issued the action plan for promoting the development of automotive power batteries (hereinafter referred to as the "plan"), In the plan, it is particularly emphasized that "universities, research institutions and key enterprises are encouraged to cooperate to carry out R & D and innovation of new system power battery products, and actively promote the research and engineering development of new system batteries such as lithium sulfur batteries, metal air batteries and solid-state batteries to give full play to their advantages in aluminum alloy product design and manufacturing with the increasing popularity of automobile consumption". In order to promote the development of power battery technology, the 32nd national chemical and physical power supply academic annual meeting was held in Wuhan on October, 2017. Dr. Miao LiXiao, general manager of Santon new energy R & D department, was invited to attend the meeting and made a thematic report on the industrialization of lithium sulfur batteries

Dr. Miao LiXiao, general manager of the R & D Department of Thornton new energy, has studied lithium sulfur batteries for nearly seven years under the guidance of academician Yang Yusheng, the pioneer of lithium sulfur batteries in China, and has made great achievements in the practical application of lithium sulfur batteries

in the face of the growing trend of power battery development through adjustment and addition, China has become the world's largest new energy vehicle market through policy guidance and support. According to the plan jointly issued by four national ministries and commissions, power battery is the heart of electric vehicles and the key to the development of new energy vehicle industry. Although China's power battery industry has made great progress after years of development, the energy density and cost of power battery products are still difficult to meet the demand for the promotion and popularization of new energy vehicles. Based on the promotion of policies and the development of power battery technology, in Miao LiXiao's view, lithium battery companies need to break through the limitations of lithium-ion batteries, timely layout and exploration of the research and development of lithium sulfur batteries is urgent, and the prospect of lithium sulfur batteries is promising

he said that the energy density of the currently popular lithium-ion battery with ternary materials as the cathode will approach the theoretical value in the next one to two years, and it is difficult to exceed 350 wh/kg. However, to manufacture 400 secondary batteries with a capacity of more than 100000 tons of wh/kg in about two years, it is necessary to develop a new lithium battery system, also known as the post lithium battery era; The lithium sulfur battery system may rise, providing more ideas and possibilities for the development and exploration of the lithium battery field

lithium sulfur battery is a kind of lithium battery with sulfur element as the positive pole and metal lithium as the negative pole. The theoretical specific capacity of sulfur and the theoretical specific energy of lithium sulfur battery using sulfur as cathode material have reached 1675 mah/g and 2600wh/kg respectively, which is much higher than the current commercial lithium-ion battery. Elemental sulfur is abundant in the earth, and the by-products of petroleum smelting can provide abundant sulfur. Therefore, the price of sulfur is very low, only 1000 yuan/ton, which is more than 160000 yuan per ton compared with lithium carbonate, the raw material price of lithium ion cathode, which is more than 160 times higher. Therefore, Dr. Miao LiXiao believes that the lithium sulfur battery with sulfur as the cathode is a very promising lithium battery. In addition, because the positive pole of lithium sulfur battery is made of elemental sulfur and carbon, and the negative pole is made of metallic lithium, the sulfur is easy to sublimate, and the sulfur in the positive pole can be recycled by simple heating. In the future, the recycling of waste lithium sulfur battery is relatively simple and the cost is low; However, the recovery process of lithium-ion battery with transition metal oxide as cathode is complex. To recover precious metals from cathode materials, either high-temperature calcination or wet pickling is not only energy-consuming, difficult, but also easy to cause more serious secondary pollution

in recent years, the research and development of lithium sulfur batteries have been basically carried out in the laboratories related to materials and electrochemistry in major universities and research institutes at home and abroad. Among them, foreign lithium sulfur battery R & D companies: Oxis and sion power have been developing lithium sulfur batteries. In 2010, sion power applied lithium sulfur batteries to large UAVs, breaking three world records for UAV Flight: the highest flight distance of more than 20000 meters, the longest dead time (14 days) and the lowest operating temperature (-75 ℃). At present, the lithium-ion battery can not make the UAV stay in the air for a long time in the high altitude and low temperature environment. Considering that the safety of lithium sulfur battery can not be completely solved at present, lithium sulfur battery will be first used in the field of UAV in the future, and the application field of UAV in the future will also be very extensive

although the research and development of lithium sulfur batteries has attracted the attention of many enterprises, most of the domestic R & D teams started after 2011. Only a few companies, such as the Institute of chemical defense, the Chinese Academy of Sciences and the University of national defense science and technology, have entered the industrialization research and development of lithium sulfur batteries. In addition, the promotion of the industrialization of lithium sulfur batteries also faces some urgent problems. Miao LiXiao said frankly that there are four main bottlenecks restricting the industrialization of lithium sulfur batteries: at present, the problem that the elemental sulfur in the positive electrode is not conductive has been basically solved; The dissolution and diffusion of the discharge intermediate multi - vitriol were also alleviated; The destruction of cathode structure caused by volume expansion after sulfur discharge is also restrained; The powdering of lithium after multiple charge and discharge cycles caused by the use of metallic lithium as the negative electrode has shortened the battery life and potential safety hazards, which has become the last bastion to be broken in the industrialization of lithium sulfur batteries

at present, great progress has been made in the development of domestic lithium sulfur batteries. According to the data, although the cycle life of high-energy density lithium sulfur batteries is still difficult to exceed 300 times, the cycle life of low-energy density (220wh/kg) lithium sulfur batteries can reach more than 1000 times, and the cycle life of high-energy density lithium sulfur batteries can reach more than 500 wh/kg (the highest reported in China can reach 900 wh/kg), It is almost 3-5 times that of lithium ion. "Although there are still many problems in the real practical process of lithium sulfur battery, I believe it is still the most likely next-generation high-energy density secondary battery. In the future, lithium sulfur battery will have a great impact on the power lithium battery market represented by ternary battery." Miao LiXiao said optimistically

made in China 2025 puts forward: "continue to support the development of electric vehicles and fuel cell vehicles, master the core technologies of low-carbon, information and intelligence of vehicles, and improve the engineering and industrialization capabilities of core technologies such as power batteries, drive motors, efficient internal combustion engines, advanced transmissions, lightweight materials and intelligent control." Miao LiXiao frankly said that at present, driven by favorable national policies and technological development, the urgent task for new energy enterprises is to increase R & D investment and accelerate the breakthrough of the technical difficulties of lithium cathode, so as to avoid the embarrassment that the core technology of lithium-ion battery cathode materials is occupied by foreign countries; In addition, just because the industrialization research and development of lithium sulfur battery is still in its infancy, it is the best period for China's new energy enterprises to seize the opportunity to gain the voice of lithium sulfur battery in the future

comments: lithium sulfur battery is in its infancy at present. Only at this time can enterprises invest in research and development to obtain core technology patents. Unlike ternary lithium-ion battery, core patents are in the hands of foreigners

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