Hualong Wu,Yanxia Zhao,Jiexi Wang,Xiaoyan Li,Kaimin Shih,Xuguang Li,Wei Liu
Resource recycling from waste-water and sludge is an important part of the 14th Five-Year Plan in China. The emerging titanium-based coagulants have drawn growing attentions due to their strong coagulation capability in water purification and value-added Ti-loaded sludge production. Management and recovery of the high value-added sludge into functional nanomaterials is highly significant for both sludge reduction and environmental remediation. The present study was carried out to investigate the recycle of the coagulated Ti-loaded sludge to produce functional C/TiO 2 composites as the anode materials for lithium-ion batteries (LIBs). It is the first time that the application of the Ti-loaded wastewater sludge derived C/TiO 2 was evaluated for LIBs. The experimental results showed that the carbon coating through in-situ carbonization of the sludge produced the C/TiO 2 composites with a high specific surface area, stable structural integrity, and excellent electrochemical properties that would facilitate Li + diffusion in long-term LIBs usage. The C/TiO 2 composites calcinated from the polytitanium sulfate-coagulated sludge at 800°C (N 2 ) exhibited the best electrochemical performance during the cycling tests (601 mAh/g at 100 mA/g after 200 cycles). The research work demonstrates the promising prospect of the recycle and value-added utilization of the Ti-loaded sludge in the production of high-performance C/TiO 2 composites for energy storage applications. This study provides a new way for the management and reuse of Ti-loaded waste-sludge.
CNTs–C@TiO 2 composite with 3D networks as electrode has been synthesized for lithium ion batteries (LIBs)/sodium ion batteries (SIBs) by a traditional solvothermal process. The composites were characterized by scanning electron microscopy, field emission electron microscopy, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The continuous 3D conductive networks, which consisted of acid-treated CNTs, provided numerous attachment sites for TiO 2 particles and carbon layers (similar to a shell) produced by the Ti 4+ -induced polymerization of ethylene glycol, thereby promoting electron and ion transfer. The composites contained 10.09 wt% CNTs (excellent conductor) and 12.75 wt% pyrolytic carbon. The Raman spectra confirmed the high degree of graphitization of the composites, and the improved conductivity resulted in outstanding electrochemical behavior. The electrochemical performance in the Li + /Na + storage of CNTs–C@TiO 2 composites was greatly enhanced, as revealed by this material’s outstanding capacity of 205 mA h g −1 at a current density of 0.1 A g −1 after 200 scanning cycles for LIBs and 148 mA h g −1 at 0.1 A g −1 over 100 cycles for SIBs.
Gang Li,Ruiyang Tan,Xiangcheng Lu,Xinyu Zhang,Chengcheng Zhang,Bohong Gao,Yuting Zhou,Ke Chen,Ping Chen,Xinyi Wang
Chemical composition and morphological optimization are both effective strategies for constructing excellent electromagnetic wave absorption (EMWA) materials. While efficient EMWA materials derived from both metal-organic frameworks (MOFs) and MXenes have been extensively studied, composites derived from the Hofmann framework with MXene have not been reported. In this study, we employed a Hofmann framework ([Fe(pz)Ni(CN) 4 ], pz = pyrazine) and MXene (Ti 3 C 2 T x ) to create new MXene@Hofmann (MH1 and MH2) composites, using a simple co-precipitation method with two different contents of [Fe(pz)Ni(CN) 4 ]. The FeNi/C/TiO 2 composites with a multi-layered structure inherited from MXene were prepared by annealing the MXene@Hofmann composites at 500, 600, and 700 °C, resulting in the formation of MH1-500/600/700 and MH2-500/600/700 composites. Their compositions, morphologies, electromagnetic parameters, and EMWA performances were characterized. For the composites with a high [Fe(pz)Ni(CN) 4 ] content, MH2-600 has a minimum reflection loss ( RL min ) value of −30.63 dB at a thickness of only 1.8 mm and the broadest effective absorption bandwidth (EAB) of 3.90 GHz at 2.0 mm, while MH2-700 exhibits superior EMWA performance with an RL min value of −34.34 dB at 1.9 mm and an EAB value of 4.96 GHz at 2.1 mm. Their impressive EMWA performance might be attributed to the synergistic dielectric loss and magnetic loss and also the impedance matching from the reasonable ratio of the magnetic and dielectric components. This work demonstrates an effective strategy for constructing EMWA materials from the Hofmann framework and MXene.
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