Rational Design of Bimetallic Zeolitic Imidazolate Framework‐Derived C, N Dual‐Doped ZnO/Co for Boosting Lithium Storage

Abstract

The advantages of LIBs are small size, light weight, low cost, high reversible capacity, long cycle performance, environmental friendliness as well as no memory effect. [3][4][5] Up to certain period of time, commercial graphite has been used for LIBs anodes. However, the graphite anode has to deal with issues, such as low charge storage capability (372 mAh g -1 ) due to the intercalation forming LiC 6 , [6] poor lithium-ion transport rate capability [7] and potential safety, [8] which hampers further application in LIBs. [9] Nowadays, transition metal oxides (TMOs), such as NiO, Fe 3 O 4 , Co 3 O 4 , ZnO, SnO 2 , etc., have been under a vigorous consideration by researchers as anode materials because of the low cost, widespread availability, environmental benignity, and much higher theoretical capacities (sometimes as high as several multitudes of commercial graphite) that they possess. [9,10] However, there still remain the limitations concerning all the TMOs, such as slower ion diffusion, low-capacity reservation, serious aggregation and drastic volume fluctuations during lithium insertion-deinsertion processes, ultimately causing the deformation of anode material, which limit their performances as lithium-ion batteries anodes. [11] There are several ways to overcome the above drawbacks. The first method is to explore the nanoarchitectures that will shorten the charge diffusion length and extend electronic pathway. [12] The second one is to construct special structures (such as hollow, yolk-shell, multishelled), which not only create large electrode-electrolyte contact sites but alleviate the volume changes during cyclic process. [13] Third, to mix multicomponent together is the promising strategy to have the benefit of synergistic effect. Thus, compared to single metal oxides, multicomponent materials favor more notable performance because of the possible synergistic effect. [14] After doping different metals, the metal of active materials can enhance the electrical conductivity and also serve as a catalytic agent, thus improving the electrochemical properties of whole electrode material. [15,16] Metal-organic frameworks (MOFs) are 3D crystalline structures formed with the help of inorganic metal clusters, metal centers, organic linkers, and organometallic components, Lithium-ion batteries (LIBs) are the preeminent technology for energy storage, having the highest energy density for large-scale commercial applications. Owing to üast assiduous studies, a good number of reported advanced anode materials possess excellent electrochemical properties. In this work, a porous C, N dual-doped ZnO/Co composite is successfully prepared by metalorganic frameworks (MOF)-template mediated synthesis method utilizing a self-sacrificing template of bimetallic zeolitic imidazolate framework (denoted as ZnCo-ZIF) and is tested as a lithium-ion battery anode material. Due to the advantageous structural and morphological features, such as well-defined open framework clusters with polyhedron crystal structure, conductive porous c...