Compared with sulfide solid electrolytes, oxide solid electrolytes have more advantages in terms of high safety and ease of production, but the improvement of ion conductivity at room temperature is still a problem of the century.

　　Recently, Toyota and the Renault/Nissan/Mitsubishi alliance respectively stated that they aim to launch electric vehicles using solid-state batteries between 2022 and 2025. At the end of last year, Ganfeng Lithium also announced that it would build a first-generation solid-state lithium battery research and development pilot production line.

　　Subverting traditional technology, solid-state batteries have become the new favorite. "Solid-state batteries that take into account high energy density and high safety are not only an ultimate goal of battery technology, but also have a tendency to come and rain on a global scale." March 21, grace Dr. Che Yong, deputy general manager and CTO of Li Energy Technology Co., Ltd., told the reporter of Science and Technology Daily.

　　Solid-state battery refers to an energy storage device in which no liquid is contained in the battery structure, and all materials exist in solid form. It is composed of "positive electrode material + negative electrode material" and solid electrolyte. Since solid-state lithium batteries have the advantages of good safety performance, high energy density and long cycle life, they are ideal power batteries for electric vehicles.

　　Compared with the lead-acid battery with a history of 150 years, the lithium-ion battery using organic electrolyte, which entered the industrialization in 1991, is still the most advanced battery on the market.

　　"With the rapid advancement of modern material science and manufacturing technology, the battery technology of the post-lead and post-lithium era has quietly come." Che Yong said, "In the near future, solid-state batteries will enter our society at a solid pace. Change our lives."

　　Che Yong explained that solid-state batteries have very significant advantages. Because solid-state electrolytes replace the potentially explosive organic electrolyte in traditional lithium-ion batteries, this solves the dilemma of high energy density and high safety, thereby eliminating electric vehicle users "Endurance anxiety" is even expected to achieve fast charging.

　　So far, through the continuous efforts of scientists, solid-state battery technology should be said to have no insurmountable technical bottlenecks, but there are still technical problems to be solved. "The core technology of solid-state batteries is solid electrolyte material technology that achieves high ionic conductivity and advanced manufacturing technology that achieves low-impedance solid-solid interface." Che Yong further explained. In terms of solid electrolyte materials, Professor Katsuji Kanno of Tokyo Institute of Technology, Japan, invented a sulfide solid electrolyte with an ion conductivity of >10-2S/cm at room temperature (surpassing the traditional organic electrolyte) in 2011.

　　Che Yong said that this technology has become the technological foundation of Toyota Motor, a leading company in the industrialization of solid-state batteries. Compared with sulfide solid electrolytes, oxide solid electrolytes have advantages in terms of high safety and ease of production. However, the improvement of ion conductivity at room temperature is still a problem of the century.