Development of High-Capacity Silicon Anode Material for Lithium Secondary Batteries

Professor Kim Hyeongjin's Team at Gwangju Institute of Science and Technology

[Asia Economy Reporter Kim Bong-su] Domestic researchers have developed a silicon-copper-carbon composite anode material with superior electrochemical performance and a simpler synthesis process compared to conventional silicon anode materials for lithium secondary batteries. Secondary batteries can be reused after charging, and their application areas are gradually expanding to electric vehicles, drones, robots, and more. This research result is attracting attention as it can dramatically improve the energy density of secondary batteries.

The research team led by Professor Kim Hyung-jin of the Graduate School of Energy Convergence at Gwangju Institute of Science and Technology (GIST) announced on the 25th that they succeeded in improving the performance and durability of silicon anodes, which are gaining attention as next-generation anodes for lithium secondary batteries. Silicon anodes are the closest technology to commercialization among existing next-generation anodes, with a theoretical capacity of up to 4200 mAh/g per unit weight, which is more than 10 times the theoretical capacity of conventional graphite commercial anodes. They are also noted as abundant and eco-friendly materials.

They can be used as large-capacity energy storage systems (ESS) and medium-to-large energy storage devices requiring high energy density and power density, such as electric vehicles, leading to fierce competition worldwide for their development. The problem lies in silicon’s non-conductive properties and the low lifespan caused by volume expansion during charge-discharge cycles, which act as obstacles to commercialization.

Accordingly, material research to improve the performance of silicon anodes is underway. For practical performance enhancement, research on technologies with low production costs and mass production capabilities is necessary.

The research team applied a simple electrode heating process to induce a silicon-copper alloy reaction and carbonize the electrode binder, successfully improving the electrical conductivity of the silicon electrode and alleviating mechanical stress within the electrode during charge-discharge cycles. As a result, the silicon-copper-carbon composite anode exhibited significantly enhanced electrochemical properties. In particular, at a high current density of 4 A/g, while the conventional silicon anode failed to charge and discharge properly, the silicon-copper-carbon composite anode maintained a high capacity of 1776 mAh/g. Compared to existing silicon anode synthesis technologies, the simple heating process applied here offers advantages such as a simpler synthesis process and higher potential for mass production.

Professor Kim said, “The core lies in the diverse applications between silicon and heterogeneous metals and the convergence of electrode processing technologies. This research on composites with heterogeneous metals goes beyond the limited use of silicon materials,” adding, “We hope it will contribute to improving the performance of lithium secondary batteries.”

The research results were published online on the 10th in the international journal on materials science and coatings, Applied Surface Science.

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