Editorial pubs.acs.org/cm
Rising to the Challenge: John B. Goodenough and Youngsik Kim, and “Challenges for Rechargeable Li Batteries” Chemistry of Materials’ 1k Club
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laboratory. This assignment gave me nearly 10 years to address with solid state chemists fundamental scientific questions about the structural and electronic properties of transition-metal oxides. The Mansfield amendment led me to accept in 1976 the position of Professor and Head of the Inorganic Chemistry Laboratory at the University of Oxford, England. Since my Ph.D. was in Physics (University of Chicago), this invitation from Oxford was imaginative and daring; it gave me the opportunity to learn a little electrochemistry and catalytic chemistry to combine with my background in solid state chemistry from my years at the Lincoln Laboratory at MIT. On approaching retirement age in England, I moved in 1986 to the University of Texas at Austin, where I am permitted to continue research at age 93. Youngsik Kim is now an assistant professor at UNIST (Ulsan National Institute of Science and Technology, 2013−present).4 CM: Given the high citation record of this review, a significant amount of research has been impacted by your findings over the years. Where did you think the field was headed when you wrote this review? In your opinion, how has this particular research field evolved ever since? JBG: When I wrote this review, I understood that the challenge to liberate modern society from its dependence on fossil fuels was going to be extremely difficult, but of critical importance for the future of mankind. To meet this challenge, it is necessary to keep focused on the fundamental problem that needs to be solved. One of the problems is the electrolyte of an electrochemical cell. What controls the “window” of the electrolyte and, therefore, the voltage limitation of the cell? A corollary was the problem of matching the redox energies of the electrode to the LUMO and HOMO of the electrolyte and the role of pinning of the redox energy at the top of the valence band of the cathode where the redox energy is in the window of the electrolyte. Raising these fundamental issues helps the synthetic chemist to go beyond Edisonian-type investigations. Since the review was written, a new direction the field has taken is a search for a solid electrolyte that can interface an alkali-metal anode; another is electrochemical catalysts for an air cathode; a third is membranes that can capture soluble intermediate species of a solid-sulfur cathode; and a fourth is the design of a flow-through liquid cathode containing a dissolved redox molecule. In my view, what has made our paper special is the importance of the problem and its introduction for newcomers to the field to the concept of redox-couple pinning at the top of a cathode conduction band. CM: What is your advice to young scientists trying to discover the next breakthrough in material science?
hen a review, published in 2010, continues to reside permanently in our most highly downloaded lists for both the past month and prior 12 months, continually since publication 5 years ago,1 it must be an incredibly useful introduction to a very rapidly expanding area of research that serves as the foundation to launching new research directions. The formative review by battery pioneer John Goodenough and Youngsik Kim, entitled “Challenges for Rechargeable Li Batteries”,2 has longevity like few papers we have seen (Figure 1a). Thus, far, it has collected 1587 citations (Web of Science), and 2429 (Google Scholar), and continues to increase in citations each year, as shown in Figure 1b. It has also been downloaded 36 252 times.3 Clearly, the area of materials for energy applications is one of the most rapidly growing areas of research, and thus this review is not only timely, but more importantly, it lays out the critical challenges faced by the lithium battery community. We (CM) caught up with Professor Goodenough (JBG), and asked him about this remarkable review. CM: At what Stage of your academic career were you when you submitted this review to Chemistry of Materials? Who was the other author on the paper, and at what stage was he? Where is he now? JBG: In 2010, I was 88 years old and Youngsik Kim was a postdoc working with me on the development of a rechargeable battery for powering electric vehicles or for storing for the grid electrical energy generated from solar and/or wind energy. I had been interested in electrochemical technology since the first energy crisis in the early 1970s; this interest led to my proposal to manufacture discharged rechargeable batteries and our demonstration of layered Li1−xCoO2, spinel Lix[Mn2]O4, and olivine LiFePO4 cathodes for the Li-ion batteries used in wireless devices. This application does not compete with the chemical energy stored in a fossil fuel. My interest in electrochemical technologies, including batteries, the solid oxide fuel cell, electrocatalysts, and solid electrolytes, was triggered by the confluence of the energy crisis of the early 1970s, my being asked to be a referee/advisor to the work at the Ford Motor Company on the sodium/sulfur battery that uses a solid β,β″alumina Na+ electrolyte with molten electrodes, and the Congressional Mansfield Amendment mandating that fundamental research at a government-supported laboratory be targeted to the mission of that laboratory. I was working at the Air-Force-supported MIT Lincoln Laboratory at the time, and after our development in the 1950s of the ferrimagnetic oxide spinels as the memory element of the first random access memory of the digital computer, we were asked, “Now that you have worked yourselves out of a job, what are you planning to do?”. I kept my job by coming back with a proposal for an alternative solution for the memory. After giving the project to others, I was put in charge of the remains of the ceramics © 2015 American Chemical Society
Published: August 11, 2015 5149
DOI: 10.1021/acs.chemmater.5b02863 Chem. Mater. 2015, 27, 5149−5150
Chemistry of Materials
Editorial
Figure 1. (a) Title and table of contents image from the Goodenough and Kim paper. (b) Plot of citations each year of this review from Web of Science.
JBG: My advice to young scientists trying to discover the next breakthrough in materials science is relatively simple: 1. Know and develop your own scientific vision and voice. 2. Enjoy what you do and believe in the importance of your explorations. 3. Be stubbornly curious without fear that your questions expose lack of knowledge; your questions may open up new ways of thinking. 4. Be willing to challenge and test conventional wisdom and dogma. 5. Compete against problems, not people; generous and open dialogue in collaboration with others, particularly those of different backgrounds and skills, opens the mind and challenges our assumptions.
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Jillian M. Buriak, Editor-in-Chief Carlos Toro, Managing Editor AUTHOR INFORMATION
Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS.
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REFERENCES
(1) The review being highlighted here is, as of July 24, 2015, the 19th and 9th most highly downloaded paper for the past month and 12 months, respectively. (2) Goodenough, J. B.; Kim, Y. Challenges for Rechargeable Li Batteries. Chem. Mater. 2010, 22, 587−603. (3) As per ACS ChemWorx, July 24, 2015. (4) https://sites.google.com/site/ykimresearch/home.
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DOI: 10.1021/acs.chemmater.5b02863 Chem. Mater. 2015, 27, 5149−5150
