Our research focuses on the direct recycling of spent lithium-ion batteries to recover cathode and anode materials from black mass. We optimize pre-treatment conditions to remove residual impurities and apply froth flotation, which separates active materials based on surface property differences, to enable a closed-loop battery recycling process. Froth flotation is a dynamic, three-phase process involving solids, liquids, and gases. To enhance separation efficiency with fine particles, the process integrates concepts from fluid dynamics, surface chemistry, and chemical reaction engineering. The recovered active materials are directly reused and reassembled into coin cell batteries to verify their performance in new batteries. 

Their electrochemical performance is evaluated through charge/discharge cycling to assess stability and capacity retention, rate capability tests for kinetics behavior, and electrochemical impedance spectroscopy (EIS) to analyze interfacial resistance. These evaluations demonstrate that the recycled active materials can perform as well as newly manufactured active materials. This direct recycling process contributes to economically and environmentally sustainable recycling technology of spent LIBs.

As global efforts toward achieving carbon neutrality accelerate, the proportion of renewable energy in electricity generation is steadily increasing. Among various renewable sources, solar power is gaining particular attention due to its technological maturity and ease of installation. Currently, crystalline silicon-based photovoltaic (PV) modules are the most widely used technology, with an average lifespan of approximately 25 years. Consequently, the amount of end-of-life PV modules is expected to grow exponentially in the coming decades. Developing technologies for recovering and recycling valuable resources from these waste modules has become essential. 

Our laboratory is actively engaged in addressing this challenge by focusing on the development of eco-friendly resource recovery technologies based on resource circulation. Specifically, we have conducted research on Strategies for the separation and reuse of PV backsheet materials, Laser reduction methods for the recovery of silver from PV modules, and Water leaching processes for the extraction of high-purity silicon. Through these initiatives, we aim to establish a sustainable resource circulation loop by efficiently recovering and recycling materials from waste PV modules, ultimately minimizing the environmental impact of the solar power industry.

With the rapid growth of the electric vehicle market, the demand for nickel—an essential component in battery materials—has been increasing significantly. In response, the development of efficient and sustainable extraction technologies for nickel from laterite ores has become a pressing challenge. Among various approaches, atmospheric leaching (AL) has gained increasing attention as a low-temperature, low-pressure method capable of extracting nickel from various types of laterite ores. 

Compared to high-pressure acid leaching (HPAL), AL offers advantages such as lower capital investment requirements and reduced carbon emissions, making it an attractive alternative for future nickel processing. Our laboratory is dedicated to developing high-efficiency extraction technologies for nickel from laterite ores. In particular, we focus on studying leaching behavior based on ore types and investigating agglomeration improvements to enhance heap leaching performance. Through this research, we aim to achieve more cost-effective nickel recovery and reduce operational expenses at pilot scale applications.

As the demand for lithium-ion batteries(LIBs) in electric vehicle increases, it is expected that a large number of spent LIBs will be generated. This results in instability in the supply of critical metal resources, highlighting the importance of efficient recycling of spent lithium-ion batteries. Our research group focuses on developing hydrometallurgical processes to effectively recover valuable metals such as nickel, cobalt, and manganese. Specifically, acid leaching and reductive leaching techniques are investigated to selectively and efficiently extract valuable metals. Subsequently, purification methods including solvent extraction and precipitation are applied to obtain high-purity metals. 

These hydrometallurgical processes are carried out at relatively low temperatures, which reduces energy consumption and environmental impact while enabling selective metal recovery. Furthermore, we investigate the reaction mechanisms involved in metal recovery to improve process understanding. Based on this, we focus on developing adaptable hydrometallurgical processes for various battery types, contributing to the advancement of resource recycling systems for next-generation battery industries.

Nickel, which is very crucial metal for industries, has affected the development of mankind. In particular, the significance of nickel in modern times is bolstered due to rapidly increasing demands for energy storage systems. There are two major ores which contain nickel: nickel sulfide ore, and nickel oxide ore which is also known as laterite. Not a small part of the existing nickel production had relied on nickel sulfide ore since mineral processing of nickel sulfide is easy to handle. Nickel sulfide ore contains low moisture and has high hydrophobic property, so nickel concentration can be achieved easily by adopting froth flotation process. However, the reserves of nickel sulfide are now being depleted and also are becoming increasingly more difficult to mine owing to the increasing mining depth caused from nickel sulfide exhaustion in the surface of earth. Therefore recently, the nickel laterite comes to the fore as the alternative of nickel sulfide since it is more abundant in earth than nickel sulfide. 

The laterite not only contains more moisture and lower nickel grade but also has more complicated crystal structure than nickel sulfide, so it is not easy to process, but the needs for developing the methods to extract nickel from laterite is becoming main problem since the international demand for nickel is increasing and the reserves of nickel sulfide is decreasing. Our laboratory is now interested in solid state reduction and magnetic separation of nickeliferous laterite. This process not only can be proceeded in relatively lower temperature compared to conventional smelting process but also can reduce reagent consumption of following processes since magnetic separation screens the gangue like SiO2 and Al2O3. Therefore, we are paying attention on solid state reduction process to reduce the environmental impact of nickel beneficiation from laterite ore.

Our laboratory investigates hydrodynamics ranging from laminar flow (hydrodynamics in porous media occurring in columns or tanks for leaching) to turbulent flow (hydrodynamics in agitated tanks for flotation). Hydrodynamics in froth flotation are simulated and used in bubble-particle interactions to predict flotation behavior. Similarly, leaching tanks are simulated to understand hydrodynamics. Moreover, simulations are used to design equipment and optimize the processes. Acquired data from simulations and experiments and is used to train machine learning models, allowing faster computations. 

Moreover, our laboratory is interested in coupling hydrodynamics with multiphysics occurring in both leaching and flotation. Some multiphysics include chemical reactions, transport of chemical species, surface chemistry based on physicochemical interactions, and bubble-particle interactions. Therefore, we are interested in combing knowledge from various fields to more realistically simulate our processes.