A complete recycling process for the cathode material of spent lithium-ion batteries is demonstrated with a simple two-step process comprised of one-pot cobalt recovery to nanostructured materials and single step synthesis of LiCoO 2 . For the facile and efficient recovery of cobalt, we employ malic acid as a leaching agent and oxalic acid as a precipitating agent, resulting in nanostructured cobalt oxalate. X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR) analysis clearly show that cobalt species are simultaneously leached and precipitated as cobalt oxalate with a high yield of 99.28%, and this material can then be used as a reactant for the synthesis of LiCoO 2 for use as a cathode material. In addition to its advantages in simplifying the process, the proposed method allows for not only enhancing the efficiency of cobalt recovery, but also enabling reaction without a reducing agent, H 2 O 2 . Through successive single-step reaction of the obtained cobalt oxalate without any purification process, LiCoO 2 is also successfully synthesized. The effect of the annealing temperature during synthesis on the nanostructure and charge-discharge properties is also investigated. Half-cell tests with recycled LiCoO 2 exhibit a high discharge capacity (131 mA·h·g −1 ) and 93% charge-discharge efficiency.

The objective of this study is to establish a system for selecting the optimum friction material to meet the seismic performance requirements of a liquefied natural gas tank with a friction pendulum system (FPS). A methodology for determining the optimum frictional material using seismic fragility analysis is suggested, and it is applied to materials with various frictional coefficients for FPS. Seismic fragility curves with two different limit states are developed to determine the optimum friction material, and a methodology for combining fragility curves is proposed. The analysis shows that a lower friction coefficient for FPSs is more appropriate for preventing failure in FPSs and the superstructure investigated in this study.