ADVANCED MATERIALS & PROCESSES | MAY/JUNE 2024 1 1 PROCESS TECHNOLOGY CHEMICAL ETCHING WIDENS PORES An international team of scientists led by Nagoya University in Japan and East China Normal University developed a new chemical etching method for widening the pores of metal-organic frameworks (MOFs). The new technique could improve various applications of MOFs, including in fuel cells and as catalysts. The researchers used chemical mixtures to etch a more open structure throughout a MOF. After an initial cycle of etching, the interior of the MOF became more porous, meaning it could be loaded with iron ions that are crucial for catalysis. This MOF has individual iron ions anchored throughout its open structure, allowing each ion to be individually catalytically active. The final catalysts, known as OP-Fe-NC, were obtained by subjecting the final MASS PRODUCING POLYMER SOLID ELECTROLYTES Researchers at Ulsan National Institute of Science and Technology, South Korea, debuted a new technique for mass-producing polymer solid electrolytes, crucial components in batteries. Departing from the traditional melt casting method, the team introduced a horizontal centrifugal casting method to overcome existing limitations. Drawing inspiration from the casting technique used in producing iron pipes, the research team successfully achieved a uniform polymer solid electrolyte by rotating the solution horizontally during manufacturing. This method ensures minimal raw material wastage and offers superior electrochemical performance, economic feasibility, and effectiveness compared to conven- tional methods. The newly developed technology enables a remarkable 13-fold increase in production speed by eliminating the need for drying polymer solutions and vacuum heat treatment, thereby streamlining the manufacturing process significantly. Moreover, the production volume can be easily adjusted by varying the size of the horizontal centrifugal casting cylinder, ensuring consistent thickness and surface quality of polymer solid electrolytes—ideal for battery production. www.unist.ac.kr. MOF to calcination treatment in an inert atmosphere. Preliminary simulations suggest that this structure will greatly improve the movement of oxygen through the material, which should significantly enhance its activity and stability. The promising results highlight the potential of OP-Fe-NC as an effective electro- catalyst for various energy storage and conversion devices. For this work, using OP-Fe-NC as a cathode catalyst delivered extraordinary oxygen reduction reaction (ORR) activity and excellent stability in acidic media, which is even better than the commercial platinum and carbon catalyst. In the fuel cell, OP-Fe-NC showed a high current density, which was close to the DOE’s 2025 target. “This work provides a new approach for designing and optimizing high-efficiency catalysts for ORR by simultaneously increasing the intrinsic catalytic activities of the active sites and effectively utilizing the active sites in the catalyst layer,” says researcher Wei Xia. Having demonstrated the potential of their method in principle, the team now plans to explore how other chemical modifications could optimize the approach to produce materials suited to different real-world situations, like contributing to the drive toward sustainable energy solutions. en.nagoya-u.ac.jp, english.ecnu.edu.cn. KULR Technology Group Inc., San Diego, received a sixfigure contract from Lockheed Martin Corp., Bethesda, Md., to develop phase change material heat sinks critical for thermal regulation of essential electronics inside long-range precision missiles. kulrtechnology.com. BRIEF Structure of the etched open-pore MOF. Courtesy of Wei Xia. Depiction of the fabrication process for solid polymer electrolytes, utilizing a custom horizontal centrifugal casting apparatus. Courtesy of Energy Storage Materials, 2024.
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