US Patent: 4,302,518
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| Electrochemical cell with new fast iron conductors
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Patentees:
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| John B. Goodenough (exact or similar names) - London, England |
| Koichi Mizuchima (exact or similar names) - London, England |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Mar. 31, 1980 |
| Granted: |
Nov. 24, 1981 |
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Jeff Joslin
Yoshino's patent JPS58219208A
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Description: |
| This patent covers an important stage in the development of the first successful lithium ion battery. This patent covers work done by Goodenough as a continuation of work done in the mid-1970s by Stanley Whittingham, a research chemist at Exxon in New Jersey. Whittingham used titanium disulfide as the cathode and a metallic lithium anode, with an electrolyte consisting of a lithium salt and an organic solvent. Whittingham's cell generated about 2.4 volts but it was unstable and prone to forming lithium dendrites that short-circuited cathode and anode, leading to explosion or fire. When Exxon ended Whittingham's battery research project he filed for a patent (# 4,049,887) and published his findings in 1976 (Science, volume 192 page 1126 ff, "Electrical energy storage and intercalation chemistry"). That paper was seen by Goodenough, who realized that replacing titanium disulfide with a transition metal oxide would produce a higher voltage and hence could have higher energy density. Using lithium cobalt oxide as the cathode and a lithium titanium sulfide anode he achieved a cell potential of 4.0 volts. And by avoiding metallic lithium, Goodenough's battery was safer than Whittingham's. The UK's Atomic Energy Research Establishment—which had played no role in Goodenough's research—filed for the patent on Goodenough's behalf in exchange for the rights to his invention.Goodenough did not have funding to continue his research and the Atomic Energy Research Establishment did not follow up on this research that they now owned. Goodenough did publish a research paper on his battery chemistry, and eventually chemist Akira Yoshino, who worked at Japanese chemical company Asahi Kasei, read the paper. Yoshino had been working on the use of polyacetylene (Japanese patent application JPS58219208A, see link), an electrically conductive plastic, as an anode in a lithium battery, and Goodenough's paper provided him with the rest of the battery chemistry he needed. However, polyacetylene proved to provide poor energy density. In an independent project Yoshino's employer developed vapor-grown carbon fiber which proved to be an excellent anode material for Yoshino's anode. The carbon-fiber anode provided the crucial combination of excellent energy density and good resistance to short-circuiting. Asahi Kasei had no expertise in building or selling batteries, but in 1987 Sony recognized the value of the invention. They again replaced the anode material, this time with graphite, and in 1991 the first commercial lithium ion batteries were shipped, inside the newly introduced Sony Handycam camcorder. The lithium ion cells were soon introduced as a stand-alone product, appearing in laptops, cell phones and other portable electronic devices. Whittingham, Goodenough and Yoshino would be awarded the 2019 Nobel Prize in Chemistry. Goodenough was 97 when the award was given, the oldest Nobel laureate in history. |
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