Lab Show Series 6: The Nobel Prize and the Future of Batteries
The ninth of October marked another late evening in the lab for researcher Jianhui WANG. But suddenly his computer erupted with a row of pop-up notifications. Wang discovered a heated online debate in several of his group chats—all centered on the just-announced Nobel laureate for this year’s chemistry award.
Three Nobel chemistry laureates—John B Goodenough, M Stanley Whittingham, and Akira Yoshino—had received the award for their contribution to the development of lithium-ion batteries and its associated electrolyte, an area of particular interest to Wang for the past six years. Wang, along with many of his colleagues and co-workers, pronounced the award “well-deserved”—a just reward for the laureates' research on lithium-ion batteries.
A quick look at Wang’s biography—and a walk-through of the researcher's lab—shows why this seasoned researcher in the field of batteries has such passion for the subject.
Wang began his career as a pre-listed student of material science at Zhejiang University in 2002. He was also a sophomore early starter of NiMH batteries, a direct-entry doctoral student in the joint program of Zhejiang University, studied at the National University of Singapore, then at the University of Science and Technology of China studying hydrogen storage in storage state chemistry from 2006 to 2011. Wang was a researcher at Kyushu University’s International Research Center for Hydrogen Energy in August 2013, and has been a full-time principal investigator in Westlake University since September 2018.
Pragmatic Nobel prize
Wang's passion for science and mathematics also made him the champion of the National Chemistry Contest. Prior to joining Westlake University, he studied lithium-ion batteries and electrolytes at Tokyo University for five years. He spoke about this year’s Nobel prize while giving us a guided tour of his own lab.
Walking into the lab, a set of 3D-printed modules welcomes us in: cell phones, laptops, EV cars—all real-life applications of lithium-ion batteries.
During the past decade, our smart phones have become less bulky, even with eye-catching features like foldable screens. Our laptops and tablets are increasingly portable, and smaller items like smart watches, wireless earbuds, and other wearables are becoming more accessible. On the other side of the spectrum, large items such as EV cars can go much further on a single battery-charge.
We take these tiny battery packs for granted, but packing more energy into a small space is closely linked to emerging technology and the fast iterations of devices which have improved our life and work. “Compared to NiMH batteries, the energy density of lithium-ion batteries is almost double,” says Wang, “thus they are an enabling component and people’s go-to option for smart phones, laptops, cars, and other mobile devices.”
The Nobel Prize in Chemistry aims to reward major contributors to achievements in chemistry. With this in mind, Wang explains the significance of batteries in the field of chemistry, “We can view batteries as power storage containers with external chargeable sources and internal power storage,” he says. “But logistically, to build a container that safely and effectively stores lithium-ion is very difficult.”
“Lithium is an active metal, highly reactive to oxygen or water, even at a minimum amount,” explains Wang. “Also, lithium-ion is sensitive to its working temperature, which typically ranges from -20 degrees to 60 degrees. Once heated inside, a series of exothermic reactions will be triggered—with the ever-present possibility of flares or even explosion. That’s why EV cars have strict requirements on their battery packs.”
Regarding the Nobel prize winners, Whittingham used TiS2 as the cathode material, Goodenough developed lithium cobaltite and lithium iron phosphate as the cathode material, and Yoshino used lithium cobaltite as the cathode material, carbon as the anode material, and uses lithium hexafluorophosphate dissolved in carbonate organic solvent as the electrolyte. Together they build the first-ever chargeable lithium-ion battery prototype. This year’s award is a testimony to the past decade of research and hard work which helped the lithium-ion battery evolve into something chargeable and storable.
The commercial use of lithium-ion batteries is promising. But as an everyday necessity, some roadblocks remain.
For instance, working temperatures must be controlled to avoid explosion and self-combustion as well as quick discharge in extreme cold weather. Energy intensity may be theoretically unbreakable, but in actual usage may require mandatory charge on a daily basis, and the ever-present difficulty of mileage anxiety.
These are issues for Wang’s team to solve in their lab of renewable energy storage and transfer. Lithium cobaltite and lithium iron phosphate have performed at their optimal efficacy in the wide application of lithium-ion batteries. So what’s the next step? Wang looks to renewable materials for the solution.
An organic electrolyte could be used by a lithium-ion battery for moving energy between cathode and anode. But how to solve the flammability and volatility issues? Wang considers a new formulation of electrolyte.
Due to the chemical property of lithium-ion, electricity can flow between cathode and anode, allowing room for self-discharge and rechargeability. This advantage also enhances the capacity of battery cells and responds well to the growing needs for higher energy density. But such materials need breakthrough technology to overcome barriers in existing applications.
“The wide application of new material is a long process,” says Wang. In his lab, twelve researchers (including six doctoral students) are working on the future orientation of batteries.
Some propose abandoning existing battery materials and develop new materials for cathode, anode, and electrolyte. Some suggest exploring new hydrogen storage techniques to boost storage efficiency. Others say that the commercial values and potentials of mainstream electrolyte formulas have not been fully tapped—for example, how about replacing flammable materials with non-flammable materials in the formation of a new electrolyte?
“The fundamental question boils down to the enhancement of energy density in the battery cells and safe use of such applications,” says Wang.
With these goals in mind, Wang will continue his journey of discovery in the upcoming decade. Some milestones in his previous research are instrumental to his ongoing developments.
In 2016, Wang successfully developed the first “single solute in a single solution” high voltage lithium-ion electrolyte based on a high-density electrolyte strategy. This elevated the voltage to 5V and increased the energy density.
In 2018, he successfully devised an organic electrolyte with fire extinction capabilities to make lithium-ion batteries safer and more durable while effectively reducing the risk of explosion and fire. This electrolyte promises to help resolve ongoing safety issues.
Based on previous research and development of the electrolyte, the next step for Wang’s team is to develop a new material for cathode and anode applications and explore next-generation clean energy storage techniques to overcome existing hurdles in energy storage density and safety.
Just another day in the lab
New technology, new material, and a new electrolyte—each iteration requires a disruptive reconstruction. Once he joined Westlake University, Wang found many like-minded partners who make interdisciplinary studies possible and boost his confidence in the face of challenges.
Nanjia ZHOU, the principal investigator in the School of Engineering, is his go-to collaborator. Zhou’s research interest is precision 3D printing at nano levels. In their collaboration, Wang and Zhou attempt to develop new lithium-ion battery cells using 3D printing, making the cells more suitable for wearable devices and precision instruments.
Recently, Wang has begun working with another two principal investigators: Dr Shi LIU and Dr Changxi ZHENG. Liu is an innovator in electrolyte development who uses the power of complex simulation to understand the link between the composition and functions of the electrolyte. Zheng is a researcher in nano characterization technology who offers a fresh perspective on the research and development of new materials.
Wang explains lithium-ion battery cells and hydrogen energy are renewable energy storage techniques. There is a high level of synergy: lithium-ion batteries symbolize the present, and hydrogen promises the future.
Scientists across the world share the aspiration that reliable technology and concrete lab findings can make our lives better and brighter. That’s why scientists keep working tirelessly in the front line of energy research. The 97-year-old Goodenough is a perfect role model. He once said, “I’m just 90-something. I still have plenty of time for my lifelong research.”
Likewise, young scientists in Wang’s team never settle for a single material or technology. They keep asking questions, making bold attempts, and moving ahead for a better future.
Written by Yi FENG | Office of Public Affairs
Translate & Edited by Ran YI | Office of Public Affairs
11 October 2019
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