Overcome the bottleneck of solid electrolytes for Li batteries

August 29, 2019

On Aug 21st, Prof. MA Cheng from the University of Science and Technology of China (USTC) and his collaborators proposed an effective strategy to address the electrode-electrolyte contact issue that is limiting the development of next-generation solid-state Li batteries. The solid-solid composite electrode created this way exhibited exceptional capacities and rate performances.

Replacing the organic liquid electrolyte in conventional Li-ion batteries with solid electrolytes can greatly alleviate the safety issues, and potentially break the "glass ceiling" for energy density improvement. However, mainstream electrode materials are also solids. Since the contact between two solids is nearly impossible to be as intimate as that between solid and liquid, at present the batteries based on solid electrolytes typically exhibit poor electrode-electrolyte contact and unsatisfactory full-cell performances.

"The electrode-electrolyte contact issue of solid-state batteries is somewhat like the shortest stave of a wooden barrel," said Prof. MA Cheng from USTC, the lead author of the study. "Actually, over these years researchers have already developed many excellent electrodes and solid electrolytes, but the poor contact between them is still limiting the efficiency of Li-ion transport."

Fortunately, MA's strategy may overcome this formidable challenge. The study began with the atom-by-atom examination of an impurity phase in a prototype, perovskite-structured solid electrolyte. Although the crystal structure differed greatly between the impurity and the solid electrolyte, they were observed to form epitaxial interfaces. After a series of detailed structural and chemical analyses, researchers discovered that the impurity phase is isostructural with the high-capacity Li-rich layered electrodes. That is to say, a prototype solid electrolyte can crystallize on the "template" formed by the atomic framework of a high-performance electrode, resulting in atomically intimate interfaces.

"This is truly a surprise," said the first author LI Fuzhen, who is currently a graduate student of USTC. "The presence of impurities in the material is actually a very common phenomenon, so common that most of the time they will be ignored. However, after taking a close look at them, we discovered this unexpected epitaxial behavior, and it directly inspired our strategy for improving the solid-solid contact."

Taking advantage of the observed phenomenon, the researchers intentionally crystallized the amorphous powder with the same composition as the perovskite-structured solid electrolyte on the surface of a Li-rich layered compound, and successfully realized a thorough, seamless contact between these two solid materials in a composite electrode. With the electrode-electrolyte contact issue addressed, such a solid-solid composite electrode delivered a rate capability even comparable to that from a solid-liquid composite electrode. More importantly, the researchers also found this type of epitaxial solid-solid contact may tolerate large lattice mismatches, and thus the strategy they proposed could also be applicable to many other perovskite solid electrolytes and layered electrodes.

"This work pointed out a direction that is worth pursuing," MA said. "Applying the principle raised here to other important materials could lead to even better cell performances and more interesting science. We are looking forward to it."

The researchers intend to continue their exploration in this direction, and apply the proposed strategy to other high-capacity, high-potential cathodes.
The study was published on Matter, a flagship journal of Cell Press, entitled "Atomically Intimate Contact between Solid Electrolytes and Electrodes for Li Batteries". The first author is LI Fuzhen, a graduate student of USTC. Prof. MA Cheng's collaborators include Prof. NAN Ce-Wen from Tsinghua University and Dr. ZHOU Lin from Ames Laboratory.

University of Science and Technology of China

Related Electrode Articles from Brightsurf:

Sludge-powered bacteria generate more electricity, faster
A new electroactive bacterium could help fuel wastewater treatment reactors.

One electrode fits all functional groups
IBS and KAIST researchers employed the gold electrode and attached the target molecules onto the electrode.

Two-dimensional MXene as a novel electrode material for next-generation display
Two-dimensional MXene as a novel electrode material for next-generation display.

Scientists probe the chemistry of a single battery electrode particle both inside and out
Cracks and chemical reactions on a battery particle's surface can degrade performance, and the particle's ability to absorb and release lithium ions also changes over time.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

High-performance large area electrode system developed for artificial photosynthesis
A research team of the Korea Institute of Science and Technology(KIST), working in cooperation with the Technische Universit├Ąt Berlin, announced that they had developed a nano-sized, coral-shaped silver catalyst electrode and large-area, high-efficiency carbon dioxide conversion system, which can be used to obtain carbon monoxide.

Nature-imitating coating makes batteries more durable and efficient
Aalto University's researchers were the first in the world to make use of carbon dioxide in the production of a battery protective coating.

Title: Two-dimensional MXene as a novel electrode material for next-generation display
Researchers in the US and Korea reported the first efficient flexible light-emitting diodes with a two-dimensional titanium carbide MXene as a flexible and transparent electrode.

Development of electrode material improving the efficiency of salinity gradient energy
Dr. Jeong Nam-Jo of Korea Institute of Energy Research(KIER) Marine Energy Convergence and Integration Research Team developed synthesis technologies of electrode material that can directly synthesize molybdenum disulfide thin films on the electrode current collector surface to contribute improving the efficiency and economic feasibility of salt gradient power generation using reverse electrodialysis.

Key progress on the MRI compatible DBS electrodes and simultaneous DBS-fMRI
Recently, collaboration between Dr. Duan Xiaojie's group (Department of Biomedical Engineering, College of Engineering, Peking University) and Dr.

Read More: Electrode News and Electrode Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.