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Development of a high-capacity, long-life lithium-ion battery anode material using silicon-based high entropy alloy

A silicon-based high entropy alloy material composed of various compositions of elements

Chemical Engineering
Prof. PARK, HOSEOK

  • Development of a high-capacity, long-life lithium-ion battery anode material using silicon-based high entropy alloy
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National Research Foundation of Korea (President Lee Kwang-Bok) announced that Professor Ho-Seok Park's research team at Sungkyunkwan University has successfully developed a high-capacity, long-life lithium-ion battery* anode material using silicon-based high entropy alloy**.

*Lithium-ion battery: A rechargeable secondary battery that uses lithium ions as the carrier and allows for repeated charge and discharge cycles through electrochemical oxidation and reduction reactions. It is used in devices such as smartphones and laptops.

**High entropy alloy: Unlike conventional alloys where minor elements are added to a predominant element, HEAs mix multiple elements in relatively equal proportions of 5% or more without a predominant element, achieving a mixing entropy of 1.5R or higher. This allows for the realization of diverse material properties through combinations of alloys.


A silicon-based anode* material has been developed to enhance the energy density of lithium-ion batteries. It is expected to overcome the capacity limits of graphite, which is currently used as a commercial anode material.

*Negative electrode: Battery materials are broadly categorized into four main components: cathode material, anode material, separator, and electrolyte. The negative electrode, or anode material, undergoes reduction reactions during charging to store lithium and oxidation reactions during discharging to release lithium.



With the global electric vehicle market expanding, battery technology competition has become increasingly fierce. Research efforts are actively underway to replace graphite, which has a capacity limit of 372mAh/g, with high-capacity silicon (theoretical capacity of 4200mAh/g), aiming to overcome this limitation.


However, silicon materials suffer from issues such as low electrical conductivity and volume expansion during charge and discharge cycles, leading to compromised long-term stability.


The research team has developed a silicon-based high entropy alloy material composed of various compositions of elements. By imparting multiple properties into a single material, they have addressed the performance degradation issues associated with silicon.


Using high-energy ball milling* synthesis method, the research team successfully developed GaGeSiP3 material, incorporating high-capacity silicon (Si), highly reactive phosphorus (P), fast lithium-ion conductivity germanium (Ge), and self-healing liquid metal gallium (Ga). They minimized the process complexity while including the advantages of these elements.

* Ball milling: Ball milling is a grinding device composed of a metal cylinder and balls, where the cylinder rotates, causing the balls and materials to grind or mix into fine powders due to friction and centrifugal forces.


In the case of GaGeSiP3 material, it has demonstrated a high rate capability* with a capacity of 949mAh/g even at high current densities, and it maintained a high capacity of 1,121mAh/g after 2,000 charge-discharge cycles.

* Rate capability: Ability of a battery to maintain its capacity retention rate depending on the speed of charging and discharging



Professor Ho-Seok Park stated, "This research not only proposes solutions to address the drawbacks of silicon, a key material for enhancing the energy density of lithium-ion batteries, but also holds significance in being the first to implement highly reactive phosphorus atoms in the recently acclaimed high entropy alloy materials."


Furthermore, this research has set design criteria for silicon-based high entropy alloy materials. As such, future research plans include synthesizing high entropy materials of various combinations to optimize structure and composition, as well as conducting additional studies on anode optimization to enhance battery performance.


Supported by the Ministry of Science and ICT and the National Research Foundation of "Center for 2D Elementary Surface Redox Energy Storage" and "Brain Pool Program" for attracting outstanding international scientists, the outcomes of this study were published in the international energy journal 'Energy & Environmental Science' (IF=32.5) on April 16th.




Figure 1. Schematic diagram of synthesis and design of high-entropy materials.

Using high-energy ball milling to mix zinc, copper, aluminum, gallium, germanium, silicon cations, and phosphorus anions in a certain ratio, synthesize a schematic diagram of silicon-based high-entropy alloy materials and demonstrate enhancement of electrochemical and mechanical properties through high-entropy alloying


Figure 2. Comparison of structure and electrochemical performance between silicon-based medium-entropy and high-entropy alloys, and schematic diagram illustrating structural changes in high-entropy alloys due to lithium-ion storage.

Schematic diagram demonstrating enhanced electrochemical performance through high-entropy alloying, and reversible structural changes due to lithium-ion storage.


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