Abstract
Transition-metal oxides are attracting considerable attention as anodes for lithium-ion batteries because of their high reversible capacities. However, the drastic volume change and inferior electrical conductivity greatly retard their widespread applications in lithium-ion batteries. Herein, three-dimensional nanoporous composites of CoO (x) (CoO and Co(3)O(4)) quantum dots and zeolitic imidazolate framework-67-derived carbon are fabricated by a precipitation method. The carbon prepared by carbonization of zeolitic imidazolate framework-67 can greatly enhance the electrical conductivity of the composite anodes. CoO (x) quantum dots anchored firmly on zeolitic imidazolate framework-67-derived carbon can effectively inhibit the aggregation and volume change of CoO (x) quantum dots during lithiation/delithiation processes. The nanoporous structure can shorten the ion diffusion paths and maintain the structural integrity upon cycling. Meanwhile, kinetics analysis reveals that a capacitance mechanism dominates the lithium storage capacity, which can greatly enhance the electrochemical performance. The composite anodes show a high discharge capacity of 1873 mAh g(-1) after 200 cycles at 200 mA g(-1), ultralong cycle life (1246 mAh g(-1) after 900 cycles at 1000 mA g(-1)), and improved rate performance. This work may provide guidelines for preparing cobalt oxide-based anodes for LIBs.