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Wen Yating,Wang Xiaobin,Huang Jingyi,Li Yu,Li Tao,Ren Baozeng 한국탄소학회 2023 Carbon Letters Vol.33 No.4
The development of functional carbon materials using waste biomass as raw materials is one of the research hotspots of lithium-sulfur batteries in recent years. In this work, used a natural high-quality carbon source—coffee grounds, which contain more than 58% carbon and less than 1% ash. Honeycomb-like S and N dual-doped graded porous carbon (SNHPC) was successfully prepared by hydrothermal carbonization and chemical activation, and the amount of thiourea used in the activation process was investigated. The prepared SNHPC showed excellent electrochemical energy storage characteristics. For example, SNHPC-2 has a large pore volume (1.85 cm3·g−1), a high mesoporous ratio (36.76%), and a synergistic effect (S, N interaction). As the cathode material of lithium-sulfur batteries, SNHPC-2/S (sulfur content is 71.61%) has the highest specific capacity. Its initial discharge-specific capacity at 0.2 C is 1106.7 mAh·g−1, and its discharge-specific capacity after 200 cycles is still as high as 636.5 mAh·g−1.
Peng Han,Jia Lin,Wen Wang,Zhihao Liu,Yating Xiang,Ting Zhang,Qiang Liu,Xiaohu Guan,Ke Qiao,Yingchun Xie,Kuaishe Wang 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2
The high-entropy alloy particles reinforced 6061Al composite was prepared by cold spray (CS) and then modified by frictionstir processing (FSP). The microstructure evolutions, corrosion, and wear behaviors of the composites were investigated. Results showed that numerous micro-pores and cracks were distributed in the Al matrix due to adiabatic shear instability andinsufficient deformation of the deposited particles for CSed samples. The average size of uniformly distributed HEA particleswas ~ 24 μm, and the geometric necessary dislocation (GND) density reached 17.1 × 1015m−2 due to large plastic deformationduring CS. Comparatively, the micro-pores and cracks were eliminated, and many fragmented HEA particles dispersed inthe Al matrix with an average size of ~ 4 μm for FSPed sample. Note that the GND density reduced to 9.8 × 1015m−2 due todynamic recrystallization during FSP. The formation rate of the oxide film was gradually greater than that of the dissolutionrate with the samples immersion in 3.5 wt% NaCl solution from 12 to 36 h, and the main corrosion mechanism was particledissolution around micro-pores and pitting for CSed and FSPed samples, respectively. In the polarization process, the FSPedsamples exhibited low corrosion tendency and high corrosion rate due to the dense and uniform microstructure, low GNDdensity, and dispersed HEA particles. The FSPed samples had better wear resistance than the CSed samples at 25 °C and200 °C. The dominant wear mechanisms of CSed and FSPed samples were abrasion at 25 °C, while the wear mechanismsof these samples were adhesion accompanied by abrasion at 200 °C.
Peng Han,Jia Lin,Wen Wang,Zhihao Liu,Yating Xiang,Ting Zhang,Qiang Liu,Xiaohu Guan,Ke Qiao,Yingchun Xie,Kuaishe Wang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3
The high-entropy alloy particles reinforced 6061Al composite was prepared by cold spray (CS) and then modified by frictionstir processing (FSP). The microstructure evolutions, corrosion, and wear behaviors of the composites were investigated. Results showed that numerous micro-pores and cracks were distributed in the Al matrix due to adiabatic shear instability andinsufficient deformation of the deposited particles for CSed samples. The average size of uniformly distributed HEA particleswas ~ 24 μm, and the geometric necessary dislocation (GND) density reached 17.1 × 1015m−2 due to large plastic deformationduring CS. Comparatively, the micro-pores and cracks were eliminated, and many fragmented HEA particles dispersed inthe Al matrix with an average size of ~ 4 μm for FSPed sample. Note that the GND density reduced to 9.8 × 1015m−2 due todynamic recrystallization during FSP. The formation rate of the oxide film was gradually greater than that of the dissolutionrate with the samples immersion in 3.5 wt% NaCl solution from 12 to 36 h, and the main corrosion mechanism was particledissolution around micro-pores and pitting for CSed and FSPed samples, respectively. In the polarization process, the FSPedsamples exhibited low corrosion tendency and high corrosion rate due to the dense and uniform microstructure, low GNDdensity, and dispersed HEA particles. The FSPed samples had better wear resistance than the CSed samples at 25 °C and200 °C. The dominant wear mechanisms of CSed and FSPed samples were abrasion at 25 °C, while the wear mechanismsof these samples were adhesion accompanied by abrasion at 200 °C.