Thackeray brought a batch of samples of magnetic iron oxide spines from Pretoria. He plans to allow lithium ions to intercalate and release these spinels at room temperature, thus proving that iron oxide spinel is a powerful new battery material, and its commercial potential is expected to exceed cobalt formulations.
Gudinaf ignored Thackeray’s hypothesis because it violates the principles of physics-the professor reminded Thackeray that spinel is similar to a “semi-precious” gemstone, in terms of structure, it cannot insert lithium ions into the Get out of gems. The physical structure of spinel hinders this activity, while oxidized diamond does not.
According to Thackeray’s recollection, although Gudinaf remained skeptical, he had reached this experimental goal under high temperature conditions when he was in South Africa. Now the problem of lowering the temperature is left.
Gudinaf said: “Well, you can try it. But you still want to find other things in the laboratory.” Then, he went to India on vacation.
Two weeks later, Goodenough returned to England. Thackeray told him the good news: “I have lithium ions embedded.”
The professor led Thackeray into his office and listened to him explain how to use a magnetic stirrer (an automated device for stirring chemicals) to mix lithium ions and iron oxide at room temperature. Thackeray immediately observed an encouraging signal: the iron oxide fell off the stirrer, indicating that it had lost its magnetism. This indicates that the spinel has absorbed lithium ions. Of course, this evidence cannot fully prove the intercalation of lithium ions.
If Thackeray is to fully prove his hypothesis, he must provide more evidence. Then, he performed a smear check on the mixture. He irradiated the smear with radiation. When taking a radiograph, you will get a series of peaks instead of one image. At this time, you need to use skills to accurately infer the structure of this mixture from the pattern of the wave peaks. This technique relies on the knowledge of ray diffraction and belongs to the category of crystallography.
Thackeray irradiated the smear twice, one before the experiment and the other after the experiment. By comparing the two results, he found that the location and relative density of the wave crests are significantly different. Something must have happened. If Gudinav is right, lithium ions cannot be embedded in the structure of iron oxide, then the two x-ray patterns should be exactly the same. But in fact, the wave peak has changed significantly, indicating that lithium ions have been inserted into iron oxide. Iron oxide spinel can be made into lithium ion electrodes!
In fact, as Gudinaf expected, there is not enough room for lithium ions in the spinel. According to Thackeray’s demonstration, the “friendly properties” of spinel are surprising-when lithium ions are inserted into it, iron ions will diffuse around to make room for lithium ions. Iron ions leave extra space. After spinel undergoes a phase change, it can absorb iron and transform it into another different material similar to rock salt. Like Gudinaf’s breakthrough lithium-cobalt oxide research results a year ago, Thackeray also devised a way to greatly increase the energy density of carbon-zinc batteries. Gudinav was both surprised and excited, because Thackeray’s idea confirmed a new principle. From a cost perspective, Thackeray’s research results have greater potential than his own.
However, Thackeray has not yet been able to create a practical battery material-a viable cathode, which is his goal. Gudinaf said there was a problem with this experiment. When he checked the data, he found that the spinel had created an obstacle. Iron oxide does not provide a clear path to allow sufficient lithium ions to enter and “settle” in the spinel structure before being “thrown out” during the charge and discharge cycle. If this material is to be truly effective, it needs more than an innovation.
Perhaps the problem lies in the type of spinel they use. The other kind may be manganese oxide. He uses LiMn2O4 to represent this material, which can remove obstacles and allow lithium ions to enter the appropriate position smoothly. While working at MIT, Goodenough’s team used manganese oxide in computer memory experiments, so he knew this material well. He suggested that Thackeray replace the oxide. Manganese spinel LiMn2O4 is expected to open the way for the manufacture of inexpensive cathodes.
In the following days, Thackeray worked in the laboratory library, preparing for manganese spinel experiments. During this time, another researcher newly hired by Bill David Goodenough joined them.
To some extent, David and Thackeray are on the same level. They are both postdoctoral assistants and entered Oxford on almost the same day. However, David felt like a “young boy” by the six-year-old South African. One reason is Thackeray’s seemingly humble attitude: he hardly reveals to others his purpose in Oxford or his achievements so far. Once, at lunch, David asked him if he would be free to go jogging together. Then, the conversation between the two almost stopped abruptly. Thackeray was reluctant to show his interest in running; he neither mentioned the “gay marathon” in South Africa, nor did he introduce himself as one of the fastest amateur runners in South Africa. For David, the more he knew about Thackeray, the more he felt that Thackeray was conservative and mysterious.
From the standpoint of pure physics, David is not bound by prejudice. Like Goodenough, he felt that Thackeray’s project basically contradicted intuition-it violated all the rules. He could not refute the crystallographic principles contained in x-rays-physics aside, Thackeray was right in this regard. However, the obstruction mentioned by Goodenough still lies ahead. If the obstruction cannot be removed, this experiment is not a feat. Da thought he could help, because he was more familiar with atomic crystallography than Thackeray. David reviewed the X-ray image of LiMn2O4 . The intercalation in this experiment was perfect, opening the way for lithium ions to enter, and foreign matter did not crush the spinel.
Thackeray was right.
He was extremely excited. One day, Goodenough and Thackeray were walking in the corridor and said: “Mike, you know that this invention may have commercial value.” Although neither of them knew how the invention was applied, Thackeray still relayed Gudinaf’s words when he called the South African supervisor, and several supervisors hurried to London. They drafted a patent application. Among the inventors, Thackeray ranked first, followed by Gudinaf, who was the instructor researcher. The owner of the patent is the South African Invention and Development Corporation-the Intellectual Property (IP) department of the South African government’s laboratory in Pretoria, where Thackeray is suspended.
Since then, Thackeray and Gudinaf argued differently as to who assumed the main responsibility for the spinel invention. The professor said that he had done the most, which meant that Thackeray was just following his instructions. Thackeray said he brought the spinel samples to Oxford; he also proposed the idea of invention. However, the fond memories of the past made the two eventually become friends who respect each other. Gudinaf, who has the style of a diplomat, summed up the incident best: “I think he can’t do it by himself. This project, I cannot succeed without his support.”
David once said that successful science “depends on people, depends on creativity.” It also depends on desire. In institutions like Oxford, scientists are desperately eager to reach the pinnacle of their respective fields, and success seems to be a matter of course. Goodenough’s laboratory can be heartfelt joy and excitement. Oxford is at the top of this new field.
However, scientific research projects are inseparable from cooperation. Goodenough said, “It is impossible for a person to just sit there and talk about it. It requires interaction and an open mind to others, so that we can get inspiration.”
However, scientific research cooperation must be done cautiously, and Gudinaf later understood this truth.