Why do lithium-rich manganese-based materials and solid-state batteries become new directions?

High cobalt prices have become unbearable for battery companies, and “de-cobaltization” of batteries is becoming a trend.

Recently, Panasonic announced that it is developing a cobalt-free power battery. Musk also said that Tesla's cobalt usage will be reduced from the current 3% to 0%. At present, Model3 has made a major breakthrough in battery raw materials, greatly reducing the proportion of cobalt used. The positive cobalt content of the battery is only 2.8%, and currently it is 8%.

In view of the still high cobalt price, the main measures of the material enterprises are to introduce high-nickel cathode materials and to develop lithium-rich manganese-based materials. The amount of cobalt used in these materials will continue to decrease, eventually achieving low cobalt or no cobalt.

Associate Professor Zhao Shizhen of Tsinghua University Shenzhen Graduate School once said that high nickel ternary is not the only choice, and lithium-rich manganese base should also be concerned.

From the cost point of view, the lithium-rich manganese-based cathode material can achieve cobalt and nickel content of only about 1/3 of ternary, and even can be cobalt-free, the cost is 20%-40% lower than ternary materials the future With the upgrade of technology, the price of lithium-rich manganese will be further reduced.

In addition to reducing the dependence on cobalt and nickel, lithium-rich manganese batteries also have the advantage of high energy density, the theoretical discharge specific capacity can reach more than 400mAh / g, the battery specific energy can reach more than 400Wh / kg.

The Action Plan for Promoting the Development of Automotive Power Battery Industry proposes that by 2020, the specific energy of the new lithium-ion power battery cell will exceed 300 wh/Kg, and by 2025, the new system power battery cell specific energy should reach 500 wh/Kg. To achieve this goal, it is inevitable to develop new and more efficient and energy-saving cathode materials to overcome and replace existing cathode materials.

At present, the domestic consensus is that 300 wh/kg is realized by high-nickel ternary positive electrode and silicon-carbon negative electrode in the near future; medium-term (2025) is based on lithium-rich manganese-based/high-capacity Si-C negative electrode to realize monomer 400 wh/kg; It is to develop lithium-sulfur and lithium-air batteries to achieve a monomer specific energy of 500 wh/kg.

Lithium-rich manganese-based materials are considered to be ideal for a new generation of lithium battery cathode materials that achieve high energy density and long cruising range. At present, mainstream cathode materials companies and power battery companies are conducting research and development of lithium-rich manganese-based materials, including many companies including Dangsheng Technology, Jiangte Motor, AVIC lithium battery, Thornton New Energy, and Penghui Energy. Lithium manganese based cathode material technology reserve.

Dangsheng Technology said that the lithium-rich manganese-based cathode material has the advantages of high specific capacity and low cost, but it also needs to seek technical breakthroughs in solving the cycle process capacity and voltage attenuation.

In terms of technological breakthroughs, the Institute of Physics of the Chinese Academy of Sciences improved the voltage decay of the lithium-rich manganese-based positive electrode cycle, reaching the target of reducing the voltage attenuation to less than 2% after 100 weeks, and made significant progress. The Peking University team first developed a lithium-rich manganese-based positive electrode with a specific capacity of 400 mAh/g can reach the target of 400 Wh/kg.

After eight years of research and development, the lithium-rich manganese-based battery is now ready for industrialization. It is the only company in the industry that produces lithium-rich manganese-based batteries. On May 28th, Yanyou Powerful Lithium-Manganese-based battery has passed the national strong inspection. At present, it has stabilized the production of 200-220Wh/kg battery. It is expected that the energy density of production in 2018 will reach 260Wh/kg. Its products are mainly used in the field of high-end passenger cars. The planned production capacity of the Yiyou Power Lithium-rich Manganese Power Battery is about 250 million to 300 million watt-hours.

Chen Guangsen, general manager of Yanyou Power, said that lithium-rich manganese power batteries combine the advantages of lithium manganate, ternary and lithium iron phosphate. It is expected that lithium-rich manganese battery will become one of the mainstream products in the next two to three years.

However, although the lithium-rich manganese base has made some progress, there is still a long way to go from industrialization. Ouyang Minggao, an academician of the Chinese Academy of Sciences and executive vice president of the China Electric Vehicles 100, said that lithium-rich manganese bases need to continue to deepen basic research. The current industrialization time is about 2025.

At present, the full application of the lithium-rich manganese-based positive electrode has the technical problems of reducing the first irreversible capacity loss, improving the rate performance and the cycle life, and suppressing the voltage decay of the cycle process. In addition, the current lithium-rich manganese-based battery still has a short life problem, and it is still difficult to meet the vehicle.

Lithium-rich manganese-based materials and solid-state batteries are considered to be the mainstay of mainstream technology for next-generation batteries. In the context of high energy density trends and rising cobalt prices, companies have added more resources to the next generation of technology, and the technical route is a matter of life and death. So who is the mainstream of lithium battery development in the future?

The page contains the contents of the machine translation.