Aug 13, 2019 Pageview：27
Due to the rapid diffusion ability of H + in aqueous solution, early rechargeable batteries mainly used strong acids(H2SO4) or strong bases(KOH) as electrolytes. At that time, the most reliable rechargeable battery was NiOOH as the positive electrode. The strong alkaline content is the nickel-hydrogen battery of the electrolyte, but we all know that the electrochemical stability window of water is very narrow, which limits the operating voltage of the rechargeable battery, resulting in lower energy density of rechargeable batteries using aqueous solutions.
In order to expand the electrochemical stability of electrolytes, many attempts have been made. In 1967, JosephKummer and Neill Weber of Ford Motor Company discovered that some ceramic materials have high Na + diffusion speeds at a high temperature of 300 °C. And using this as an opportunity to develop a rechargeable battery using the molten metal Na negative electrode and the molten S/graphite positive electrode, the high working temperature makes it difficult for the battery to find a useful place in practice. But this does not prevent the battery from bringing solid-state electrolyte technology to people's eyes, which also paves the way for the rise of all-solid batteries today. Googenough, who was working at MIT's Lincoln Laboratory, saw the prospect of this technology, followed the technology, and developed Na1 + xZr2SixP3 with HenryHong's high Na + conductivity. xO12 electrolytes, but due to the low conductivity of solid electrolytes at room temperature, did not attract much attention at the time.
In the 1970s, an unexpected oil crisis swept through the United States. At that time, the United States was overly dependent on oil imports, so this oil crisis hit American society. Since then, the United States has begun to vigorously develop renewable energy, such as wind and solar energy, to reduce dependence on fossil energy such as oil. The development of wind and solar energy will have to face a problem. These renewable energy sources basically depend on eating food and are difficult to adapt to the requirements of grid stability. Therefore, the development of renewable energy can not be separated from the Advancement of energy storage technology.
Metal lithium has the advantages of low potential (-3.04Vvs standard hydrogen electrode) and high specific capacity (3860mAh/g), and is a very excellent anode material. Early lithium primary batteries use metallic lithium as the negative electrode and organic solvent as the electrolyte. Good results have been achieved, so research on rechargeable batteries began to focus on metal lithium secondary batteries. Researchers used European chemists in the 1960s to find that Li+ is reversibly embedded in layered transition metal sulfides. Principle, an initial metal lithium secondary battery was prepared using a metal sulfide as a positive electrode. In the 1980s, Canada's Moli Energy first introduced Li/MO2 secondary batteries using lithium metal as a negative electrode. This battery also allowed Moli Energy to dominate the global battery market, but unfortunately the lithium was second in 1989. A continuous fire and explosion accident occurred in the battery, which led to a large-scale recall of the battery worldwide. Since then, the company that briefly dominated the global battery market has been devastated and eventually acquired by NEC Corporation of Japan. NEC invested a huge amount of manpower and time to carefully analyze tens of thousands of batteries, and finally found the lithium cdr that caused the battery to explode, but did not find a way to solve the lithium dendrites, because of safety. The problem could not be solved, and the lithium metal battery slowly faded out of our view.
At this time, Goodenough is studying lithium-containing metal oxide LiCoO2 at the University of Oxford, England. The theoretical capacity of LiCoO2 material is 274mAh/g, but not all Li+ can reversibly desorb. When Li+ is out too much, it will destroy the stability of the structure. Sexuality, causing the collapse of the material structure, Goodenough strives to finally achieve more than half of Li reversible out of LiCoO2, so that the reversible capacity of LiCoO2 material reaches 140mAh / g or more, this result eventually led to the birth of lithium-ion batteries. AkiraYoshino, who was working at Asahi Kasei, used LiCoO2 as the positive electrode. Graphite material was used as the negative electrode to develop the earliest lithium-ion battery model. This technology was finally adopted by Sony Corporation. In 1991, the world's first commercial lithium-ion battery was introduced. The lithium ion battery adopts graphite material as the negative electrode to avoid the appearance of lithium metal of the negative electrode, thereby avoiding the formation of lithium dendrites, thereby greatly improving the safety of the rechargeable battery. Since then, with the advantages of high energy density and high safety, lithium-ion batteries have been rushing all the way, quickly leaving other secondary batteries behind them. In just over a decade, lithium-ion batteries have completely occupied consumer electronics. The market has expanded into the field of electric vehicles and achieved brilliant achievements.
However, the development of secondary batteries is a race that never ends. As the battery's specific energy index continues to increase, the traditional lithium-ion battery can no longer meet the new demand. To further improve the battery specific energy, Goodenough is over 90 years old. Also turned to the all-solid battery. The all-solid-state battery replaces the liquid electrolyte in the traditional lithium-ion battery with a solid with ion-conducting ability, and the solid electrolyte has good strength, which makes the use of the metal-lithium negative electrode possible, and leaves sufficient energy for the lithium-ion battery to increase the specific energy. space. After more than ten years of development, solid electrolytes have also developed various types, such as ceramic oxide electrolytes, sulfide electrolytes and polymer electrolytes. The performance has also been greatly improved. The room temperature ionic conductivity of some ceramic oxide electrolytes has been It is comparable to liquid electrolytes, making the application of all solid-state batteries possible. Goodenough's lab at the University of Texas at Austin has now developed an all-solid-state battery using solid-state electrolytes that maintains good electrochemical performance and does not produce lithium dendrites during long-term cycling. Goodenough believes that with the gradual maturity of all-solid-state battery technology, electric vehicles will be pushed to replace traditional internal combustion engines and reduce the consumption of fossil energy.
The old man is screaming, and he is aiming for a thousand miles. The martyr's old age is overwhelming. Goodenough is still fighting in the front line of scientific research at the age of 96. How can we, the younger generation, relax? Finally, we pay tribute to Goodenough again.
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