Ni-MOF@MWCNT core/sheath composites with enhanced lithium storage capacity and cycle stability

Metal-organic frameworks (MOFs) have garnered significant interest as promising anode materials for lithium-ion batteries (LIBs). Nonetheless, their application is hindered by limited rate capability and insufficient cycle performance. Herein, core/sheath structured Ni-MOF@multiwalled carbon nanotube (MWCNT) composites were hydrothermally synthesized by employing 2, 3, 6, 7, 10, 11-hexahydroxytriphenyl (HHTP) as ligands and Ni²⁺ as central metal ion nodes. MWCNTs can serve as efficient highways for rapid electron transport in this unique structure. The Ni-MOF nanorods, grown on the sidewalls of the MWCNT matrix, offer abundant accessible active sites for Li⁺ storage. As anticipated, the optimized Ni-MOF@MWCNT-30 achieved a lithium storage capacity of 518 mAh g^-1 after 200 charge/discharge cycles at 0.2 A g^-1, representing a remarkable 318 % increase over the bare Ni-MOF (124 mAh g^-1). Furthermore, after 1000 charge/discharge cycles at 0.5 A g^-1, it maintained a discharge capacity of 446 mAh g^-1 with a coulombic efficiency of 99.2 %. These findings provide insights for designing MOF-based anode materials for next-generation LIBs, emphasizing large capacity and excellent cycling performance.