ZIF-8/ZIF-67 derived carbon anodes from bimetallic precursors and their lithium storage characteristics

Lithium-storage capability of anode materials is pivotal to improving the energy density of lithium-ion batteries (LIBs). Although graphite offers excellent reversibility and a low operating potential, its theoretical capacity is limited to 372 mAh g −1 . Therefore, developing alternative carbonaceous anodes with higher reversible capacity while maintaining competitive rate capability and cycling stability is of considerable interest. To overcome this bottleneck, zeolitic imidazolate framework (ZIF) materials are selected as precursors, and a facile calcination approach is adopted to tailor the microstructure of ZIF-derived carbon for constructing high-capacity LIB anodes. Bimetallic ZIF-derived carbon (BMC) is prepared by one-step pyrolysis at 950 °C using ZIF-8/ZIF-67 precursors with adjustable Zn/Co molar ratios, in which Co species are successfully incorporated into carbon frameworks. The microstructure, phase composition and pore structure of as-prepared BMC are systematically characterized by multiple microscopic and spectroscopic techniques. Electrochemical tests demonstrate that BMC samples with Zn/Co molar ratios of 1:1, 1:3 and 3:1 deliver reversible specific capacities of 465.6 mAh g −1 , 432.7 mAh g −1 and 408.1 mAh g −1 after 100 cycles at 0.1 A g −1 , respectively. Among them, the sample from 1:1 Zn/Co precursor shows good lithium-storage performance. This work provides a feasible strategy for structural and compositional regulation of ZIF-derived carbons toward high-performance LIB anode applications.