This study is focused on the controllable coating of the carbonyl iron (CI) particles widely applied in magnetorheology. These particles were grafted with poly(glycidyl methacrylate) (PGMA) with narrow polydispersity via surface-initiated atom transfer radical polymerization. Two types of core-shell particles differing in molecular weights of grafted polymer chains were synthesized. The effect of shell thickness on the thermo-oxidation stability of particles as well as the sedimentation stability of their silicone oil suspensions was evaluated. The successful coating process was confirmed by Fourier transform infrared spectroscopy and energy-dispersive spectrometry. The differences in the magnetic properties of bare and coated CI particles were clarified through vibrating sample magnetometry. Due to the controllable length of the PGMA grafts, the magnetic properties remain almost the same as those for bare CI. The magnetorheological (MR) behavior of silicone oil suspensions containing 60 wt% of bare CI particles as well as PGMA-coated analogues was investigated in the absence and in the presence of various magnetic field strengths, demonstrating the negligible impact of surface modification on final MR performance. Thus, the grafting of the particles with PGMA negligibly affected magnetic properties but considerably enhanced thermo-oxidation and sedimentation stabilities. Finally, a novel tensiometric method for sedimentation stability measurements of MR suspensions was successfully implemented.

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To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materials for lithium-ion batteries (LIBs), a facile strategy is developed to construct three-dimensional (3D) hierarchical porous Ti3C2/bimetal-organic framework (NiCo-MOF) nanoarchitectures as anodes for high-performance LIBs. 2D Ti3C2 nanosheets are coupled with NiCo-MOF nanoflakes induced by hydrogen bonds to form 3D Ti3C2/NiCo-MOF composite films through vacuum-assisted filtration technology. The morphology and electrochemical properties of Ti3C2/NiCo-MOF are influenced by the mass ratio of MOF to Ti3C2. Owing to the interconnected porous structures with a high specific surface area, rapid charge transfer process, and Li+ diffusion rate, the Ti3C2/NiCo-MOF-0.4 electrode delivers a high reversible capacity of 402 mAh g−1 at 0.1 A g−1 after 300 cycles; excellent rate performance (256 mAh g−1 at 1 A g−1); and long-term stability with a capacity retention of 85.7% even after 400 cycles at a high current density, much higher than pristine Ti3C2 MXene. The results highlight that Ti3C2/NiCo-MOF have great potential in the development of high-performance energy storage devices.

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