'10x Storage Capacity'... Commercialization of Silicon Anode Materials Breaks Ground

KAIST Research Team
Visualizes with Atomic Microscope, Confirms Internal Structure
Enables Identification of Volume Change Causes During Charge-Discharge

(From left) Dr. Gun Park, Ph.D. candidate in Materials Science and Engineering at KAIST, Professor Seungbeom Hong

[Asia Economy Reporter Kim Bong-su] Domestic researchers have paved the way for the commercialization of silicon anode lithium secondary batteries that can store much more electricity than graphite anodes.

The Korea Advanced Institute of Science and Technology (KAIST) announced on the 8th that Professor Hong Seung-beom's research team in the Department of Materials Science and Engineering, in collaboration with LG Energy Solution, succeeded in developing a methodology to quantitatively extract electron conduction channels within electrodes at nanoscale resolution without distortion signals. The research team identified the cause of capacitive current, a distortion signal occurring during the operation of Conductive Atomic Force Microscopy (C-AFM) on samples with large surface roughness such as electrode materials, and removed this distortion information based on Pearson correlation analysis.

Applying this methodology to silicon-graphite composite anodes, they visualized electron conduction channels according to conductive additive components and successfully demonstrated the electrical and electrochemical superiority of electrodes applied with Single-Walled Carbon Nano Tubes (SWCNT).

Through this study, the research team showed that in systems with large volume changes of active materials, such as silicon-based electrodes, SWCNTs, which have a linear structural advantage compared to conventional point-type conductive additives, are favorable for securing stable electron conduction channels. Furthermore, in composite electrodes containing SWCNTs, they demonstrated that pulverization of active materials was more suppressed even after 130 cycles, hypothesizing that the heterogeneity of electron conduction channels can also affect the structural stability of active materials.

With the explosive increase in demand for lithium secondary batteries with high energy density, research on silicon-based anode development is actively underway. Silicon active materials have a higher capacity value (4200 mAh/g) compared to conventional graphite anode active materials, establishing themselves as a promising candidate for high-energy-density lithium secondary battery anodes.

However, the high volume expansion and contraction rate of up to 400% during charging and discharging hinders the commercialization of silicon active materials. The drastic volume changes in silicon-based anodes particularly have a significant adverse effect on the electron transport system within the electrode, and various conductive additive systems are being actively studied to compensate for this. Securing electron conduction channels within electrodes is essential to induce uniform electrochemical reactions within active materials, but there has been little research on methodologies to visualize this at nanoscale spatial resolution.

Dr. Park Geon, a first author and doctoral candidate in the Department of Materials Science and Engineering at KAIST, said, "We are conducting follow-up research on the degradation of electrochemical properties of electrodes caused by heterogeneity in electron conduction channels. It is exciting to explore phenomena that have not been observed before based on nanoscale visualization." Corresponding author Professor Hong Seung-beom said, "Identifying the causes of distortion signals and quantitatively removing them is very important in the field of imaging. We hope that the methodology developed this time will be applied to strengthen electron conduction channels within electrodes and help accelerate the advancement of silicon-based composite anodes."

This study was published in the international journal ACS Applied Materials & Interfaces.

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