Comparison study of electrochemical properties of porous zinc oxide/N-doped carbon and pristine zinc oxide polyhedrons

Key Words:Zinc oxide; Polyhedrons; N-doped carbon; Anode; Lithium ion battery

Abstract:An in-situ calcination strategy has been developed for the synthesis of porous zinc oxide/N-doped carbon (ZnO/NC) polyhedrons, in which zeolitic imidazolate framework-8 (ZIF-8) serves as the precursor. The ZnO/NC polyhedrons with a hierarchical architecture possess a high specific surface area of 390.7 m(2) g(-1), high nitrogen content (19.99 at%,), and robust pore structures. The porous N-doped carbon frameworks can not only increase the electronic conductivity of ZnO, but also provide interior space for the fast diffusion of Li+ ions and accommodate the volume variations during the charge and discharge cycles. When evaluated for lithium storage capacity, the hierarchical ZnO/NC polyhedrons exhibit high reversible discharge capacity (834.3 mAh g(-1) at the initial low rate of 0.5C, 1C = 978 mA g(-1)), superior rate performance (399.2 mAh g(-1) at 5C and 253.5 mAh g(-1) at 10C), and excellent cycling stability (677.9 mAh g(-1) at 1C after 400 cycles). The reasons are explored in terms of the well-confined primary nanocrystals (5 nm), and the finely constructed interconnected pores of the N-doped carbon networks, which facilitate the fast and effective transfer of Li+ ions and electrons, and accommodate the large volume expansions. (C) 2015 Elsevier B.V. All rights reserved.

Volume:285

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Translation or Not:no