A professor at the University of California, San Diego, Shirley Meng is one of the world’s leading experts in nanomaterials for energy storage and conversion, striving to push the transition of the energy sector toward efficient and sustainable energy storage technologies.
Born and raised in Hangzhou, China, Meng pursued her higher education in Singapore where she had her “magic moment” while exploring superconducting oxides during an internship that formed the steppingstone to her career in materials science and engineering. Meng currently holds the Zable Endowed Chair in Energy Technologies and is also the founding director of Sustainable Power and Energy Center at UCSD.
How did you develop a passion for science?
I am an immigrant. I was born in Hangzhou, China — it has a beautiful west lake. I think people know it more now because Alibaba was built there [and] Jack Ma was from there.
When I was seventeen, I got a full scholarship to go to Singapore for my undergraduate degree, and from there, I had the opportunity to meet a few very good professors, who introduced me to materials science and engineering. I think one of the things [they] convinced me was that history is defined by materials — the Stone Age, Bronze Age, Silicon Age etc. — and they are a very important part of human history.
I was originally hoping to study aerospace and mechanical engineering to be able to work for a company like Boeing, as I was always fascinated by light-weight strong materials. Unfortunately, or fortunately, I failed at an internship interview, so I didn’t get into the company. Instead, I found another professor who was working on superconducting oxides. It was then that I had a wild moment when I made the superconducting oxide that enabled magnetic levitation during an experiment. That was the “magic moment” when I decided that I would pursue materials science and engineering for the rest of my life.
Who are your role models or earliest influences that encouraged or inspired you to take up a research career?
I think everybody’s list of role models starts with their parents. My mom and dad are both quite well-educated, and my mom taught me that a woman must be independent financially and spiritually. My dad is a civil engineer who works on hydroelectricity, building dams. I always joke that my family has a very good track record for renewables.
When I was seven years old, my father gave me a book about one hundred Nobel laureates, which contained the stories of their personal lives. I still have that book after 30 plus years! I was quite shocked to find only one woman in the entire book. So, Marie Curie was definitely one of my earliest inspirations. It was also inspiring how she was not able to get the award [but her husband stood up for] her saying: “I refuse to receive it unless you give to Marie”. She also said something that was really a guiding principle for me for the rest of my scientific career: “Nothing in the world is to be feared of, it is only to be understood”.
I would like to say that I am not the kind of person who holds onto an idol, but I admire characteristics and merits in the people I have met. For instance, Dr. Stanley Whittingham (last year’s Nobel Laurette) came up and talked to me after my MRS conference presentation in 2005. I was totally blown away, because, you know, for a professor like him to have a discussion with me! He was extremely humble, and is really, really, down to earth. Him being humble, being someone who is in a position to educate other people is really a privilege. So, I think Dr. Whittingham definitely has become a good role model for me in that sense; no matter how high [your] achievements are, you have to always be respectful to the next generation of scientists. That’s really inspiring.
What were some of the challenges you faced during your career?
I would say that I am very fortunate because I also have a really good work-life balance. My husband is in academia as well. Being able to have a family during the tenure-track period was awesome and having my son really put everything into perspective.
When I was a graduate student, there were senior folks telling me “you are not supposed to have children when you are on your tenure track, you need to figure out your career first”. I think I am very glad that I didn’t listen to that advise because in the end, it was really important for me personally. I think everyone should have their option/freedom to choose what lifestyle they want. I think, I am someone who, if I am really focused on work, I will eat instant noodles, or not drink water for the whole day. But my family always reminds me, “time to take a break”. In fact, that [break] energizes your body and mind, and you can actually work better. Over the past decade, since I had my son, I just always feel he is basically someone who I can learn a lot from because he is always up for a challenge. If anything new is introduced to him, he is like, “Okay, I will give it a try”.
I always tell my students that along the way, we forget that when we were children, we were always up for any new challenge in life. But we start to worry about things and lose curiosity. The challenge of work-life balance is difficult in the beginning, but it really pays off later. Don’t delay your life because of your work or vice versa.
What would you say has been your most impactful contribution to the field?
My group is built around the fact that being able to visualize the invisible things at the materials interface or bulk can give you critical insights to actually mitigate issues with materials, and which allows us to better design experiments and have higher success rates in mitigation strategies.
I was very well-known in the battery field for using all the “fancy tools”. I like to use X-ray, electron beams, and neutrons to look at materials or devices. For instance, I think about 13 years ago, the scanning transmission electron microscope with aberration corrections was very new, and I was one of the first few academic scientists to use this tool to locate the oxide interface, where we see 2-3 nm phase changes on the surface. That’s also the reason why all the high-voltage cathode materials have some kind of surface coatings, and those can be visualized. I think that was one of the studies that I am personally most fond of; being able to relate the structure to the property. This is materials science, it is the bread and butter of our work.
You mentioned in a recent article that it would be hypocritical of proponents of sodium-ion batteries to not consider how to deal them at the end of their life. How far do you think we are in achieving sustainability in batteries?
This is actually one of the major challenges I think our society is going to face. I am a Tesla driver, [and we eventually] have to think about what to do with these batteries.
Take Li-ion batteries [for example], less than 5% of the total lithium batteries in the world are recycled. Lead-acid batteries, on the contrary, are 99% recycled. The only place they are not recycled are in places like Africa where they don’t have very good government regulation. This is also something that a lot of academic researchers think that it’s not their job to think about, but I think that’s the wrong way of doing things. It is absolutely our job because if you have a material where its compositions contain very valuable elements (for instance, cobalt is very valuable or say, rare-earth elements), it’s pretty obvious you have to recycle.
The question becomes: if you have a system where there’s no expensive element, [what’s the incentive to recycle?] Think about plastics! The reason we have such a disaster with plastics is because there are no expensive elements used in them. There’s no commercial value for the industry to recycle, so we don’t. The industry is not doing it, so the only place it’s possible is the government, but I think the government needs academics and industry to work together to have a program where recycling or reuse can be established.
Working in sodium-ion batteries, I want to say, is one of [my favorite] aspects of my research, however, I think this is also the most [challenging] for me. In the 1960s actually, sodium-ion batteries were widely studied. If you look at the periodic table, in those early days, when they looked at the standard reduction potential, sodium lay in a good position because lithium’s potential is too negative. A lot of brilliant scientist in the late 1960s and early 1970s worked on sodium-ion batteries but then lithium chemistry took off, and ever since sodium has always lagged behind.
Sodium has the potential to be an energy storage solution, but it does no good to always compare it with lithium. The fact is, based on the thermodynamics, you cannot build a sodium-ion battery that gives you very high voltage. Now, if we instead think about sodium for large-scale grid storage, we are talking about potentially megawatt-hour storage, which means we’ll have containers of large volume.
The other thing is, batteries have always been considered as a consumable, but with sodium batteries, we want people to think of them as assets. Think about your house; you don’t expect to have to rebuild your house ten years later, right? So, I think that a mindset change is required. It is very, very difficult to engage or even encourage industry to think of batteries as an asset, but being able to recycle and reuse batteries could enable that. I hope more people can realize this, that it’s scientifically possible and can be done.
What are your future plans?
At this point our battery research is divided between three different areas. I truly believe that maybe as soon as 2050 we’re going to electrify and digitize everything. Everything! I mean literally everything. Think internet of things! But how do you connect everything to each other, have them talk to each other, send and receive signals? So, [in this sense] those are the battery chemistries or designs we work on. We want to make batteries that are “invisible”, that work on things like sensors. We have a small group of graduate students who are working on areas like 5G, communication between buildings, between cars, cars and buildings, and so on.
The second area is batteries for electric vehicles. We are really focusing on safety and longevity. Safety obviously has improved from one in one hundred thousand failures to one in ten million. But that means if we ship out one billion cells, we will still have one hundred accidents every year. The battery field is really trying to improve safety as well as the cycle life. You might have heard about the million-mile battery! It’s definitely possible, thermodynamically nothing is prohibiting it and the goal is very achievable, I would say.
The majority of my other research efforts will be put into the grid, to think about how to deploy megawatt-hour batteries, coming back to this idea where turn the battery into a real asset. I have been spending quite a bit of time talking to investors, educating them on how batteries can be huge assets — these are “banks” for electrons!
I think I will be very busy for the next few decades. We have to help the world transition to a more efficient and sustainable power. We’re transitioning to an era of better technologies. Burning things to generate mechanical motion, to then get electrons, is so inefficient. If you want, you can electrify everything, by going directly from chemicals to electrons, you can directly use the electromotor for motion generation.The next generation of scientist and engineers will find that burning things is such an outdated, past technology.
Do you feel women are well represented in STEM fields in general? If not, what can be done to address this?
Two weeks ago, I gave a talk at the microscopy M&M meeting and I addressed this question by recommending people watch a YouTube video by Claudia Goldin from Harvard University. When we look at the gender issue, we must put the axis of time into the analysis. What I really liked about her presentation is that she talks about women’s progress over time. It’s not just specific to the STEM. It’s been one hundred years since women were allowed to get a degree, work and build a career. I’m very lucky because I was born at the time where there were already more and more women getting bachelor’s degrees. [Comparatively,] the world is already much better for women.
2016 was the twentieth anniversary since a Harvard professor published a paper in the New York Times about unequal pay in STEM fields, and I think we’re still paid 85 cents per dollar compared to men. I personally have experienced that. [To fix this,] number one is really for the leadership to reinforce the equal pay rule. In 2016, I was one of the people in my institution who fought with the administration about the fact that women are paid less. We [women] are not trained to negotiate so we need to collectively do so.
But if you look at the last hundred years, women have progressed quite a lot. Yes, we’re still experiencing these same issues because we have to deal with the values of older generations, but I’m very optimistic and we can get there, I think, if we do things right, for instance, equal pay or encouraging more girls to play with legos or build electric circuits. In China in the 1980s, they put us girls into sewing classes and boys into radio making. I just told my dad there’s no way I would do the sewing class, I still don’t know how to sew. But my dad negotiated with the school to put me in the radio building class. So, if more parents stand up and do the right things, the world will change to a better place.
Besides this, I think, one of the most important things to help address this issue is that men must be our partners. I cannot stress the importance enough. On a small scale, for any event supporting women, we have to invite our male colleagues. When people are educated and experience other people’s sides, they are more willing to make the change.
What are your hobbies or interests outside of the lab?
I have something I can show you! My hobby is brush calligraphy. Some people like to do yoga, but I absolutely cannot. I don’t know why, but whenever they ask me to empty everything from my mind and breathe all my deadlines come up.
Perhaps because I was trained to do brush calligraphy from when I was a child, I find peace in it. Chinese calligraphy is like yoga for me. This [image right] is a very famous Buddhist scripture that is 260 words that takes 3-4 hours. You cannot make a single mistake when you are doing calligraphy, otherwise you cannot keep it, you have to throw it away and start all over again.
That’s very interesting! Chinese calligraphy is indeed a unique hobby to pursue, one that requires patience and a clear mind.
Yeah, I think again I have to thank my parents. At that time in China, engineers and accountants didn’t earn a lot of money. I wanted to pursue the piano, but we couldn’t afford the class. The only thing my dad could afford was calligraphy. Life is a very interesting journey because you can only truly see the impact of some events many years later.
Calligraphy is something I really enjoy and I think that is quite different from science. I sometimes do the poem from the Song and Tang dynasties, from 600 or 800 AD in China, and think about the beautiful way that artists and scholars expressed and articulated their ideas. Writing in English is, of course, different, but then the way you construct the message is more important than the big words that you use. I think calligraphy helps a lot with the thinking process.
To learn more about Meng’s work in developing long-lasting sodium-ion batteries for grid-scale energy storage, read her recent paper published in Advanced Energy Materials, which is part of a recent Virtual Issue “10 Years of Advanced Energy Materials Research” celebrating the 10th anniversary of the journal.