The solid-state battery is a secondary battery in which the electrolyte is a solid material. It differs from the traditional lithium-ion battery in that it replaces the electrolyte and separator of the traditional lithium-ion battery with a solid electrolyte. Because it has better performance than traditional lithium-ion batteries in terms of safety, energy density, and cycle life, it is considered as the next-generation battery technology.
In principle, there is no difference between a solid lithium battery and a traditional lithium battery: a traditional liquid lithium battery is called a "rocking chair battery". The two ends of the rocking chair are the positive and negative poles of the battery, and the middle is a liquid electrolyte. Migration in liquid to complete the shuttle between the positive and negative electrodes to achieve charge and discharge, and the electrolyte of the solid state battery is in a solid form, which is equivalent to the place where lithium ions migrate to the solid state electrolyte.
On the R & D and industrialization of solid-state batteries, South Korea is dominated by the business community. Under the guidance of government departments, major domestic automobile battery manufacturers have jointly developed all-solid-state batteries. At present, South Korean companies studying solid-state batteries mainly include Samsung SDI, LG, and Hyundai Motor. Among them, Samsung, LG, and SK Innovation have chosen to set up a joint fund to jointly develop solid-state batteries. Hyundai did not participate in the above three alliances, but chose to enter the solid-state battery industry chain through independent development, cooperation with universities, and external investment. In terms of patents, the distribution in South Korea is relatively concentrated, with Samsung SDI, LG and Hyundai accounting for more than 50%; in terms of technology paths, sulfide electrolytes are the main ones.
A few days ago, Samsung Advanced Research Institute and Samsung Japan Research Center published a paper entitled "Achieving High Energy Density and Long Endurance All-Solid-State Lithium Battery with Silver-Carbon Negative Electrode" in the journal Nature Energy. Samsung's solution to the problem of lithium dendrite and charge and discharge efficiency that plagued mass production of all-solid-state batteries.
It is understood that this solution will help Samsung's all-solid-state battery to achieve an energy density of 900Wh / L (different from the unit of measurement of Wh / kg, which is not convertible due to different material densities), and more than 1,000 charge and discharge cycles And 99.8% Coulomb efficiency (also known as charge and discharge efficiency). Although China's more advanced solid-state battery technology can also achieve more than 1,000 charge and discharge cycles, the Coulomb efficiency is currently not close to 100%.
According to the paper, Samsung introduced a silver-carbon composite negative electrode, a stainless steel (SUS) current collector, a pyroxene-type sulfide electrolyte, and a special material coating to treat the negative electrode, electrolyte, and positive electrode of solid-state batteries, effectively solving lithium dendrites. Growth, low Coulomb efficiency, and interface side reactions are the core issues facing the three solid-state battery mass production, pushing solid-state battery technology further from industrialization. The breakthrough of key technologies means the start of the solid-state battery market card competition, including players such as Panasonic, Ningde Times, Toyota, and BMW. It is foreseeable that in the next five years, solid-state battery technology will become the key to the technological confrontation and industrial layout of these companies. Samsung will have a considerable lead in this competition because it took the lead in achieving a technological breakthrough.
In the previous research and development of solid-state batteries, lithium dendrite problems, Coulomb efficiency problems, and interface side reaction problems have stumped R & D teams in many battery fields. At present, it can be said that the key difficulties of solid-state battery technology have been overcome by Samsung, and solid-state battery products are one step closer to mass production. This phenomenon means that in the next five years, car companies, power battery suppliers and cross-border players who are deploying the solid-state battery field will follow this line of research to promote the solid-state battery field from R & D to mass production. breakthrough.