Crystallization of transition metal oxides within 12 seconds

Abstract

A general and programmed fast crystallization process (about 12 seconds) was designed to synthesize binary (MOx) and ternary (ABO3, A2BO4) metal oxide nanomaterials with controllable sizes and composition. The fast crystallization process mainly included the burning of metal-nitrate–filter-paper without additional energy supply and it can lead to the formation of exceptionally fine binary and ternary crystallites with sizes of ∼10–20 nm. The thermodynamic reduction potential of the metal-nitrate–filter-paper burning system can be estimated to be between −0.26 and 1.72 V, which can favor the occurrence of redox reactions, i.e. Cu2+ → Cu+ → Cu, Ni2+ → Ni, Co2+ → Co3+, Ce3+ → Ce4+, and Pr3+ → Pr4+. When used as anode materials for lithium-ion batteries, most of the as-burned metal oxides displayed high cycling stability. The discharge capacity of CoO nanoparticles can reach as high as 501.1 mA h g−1 after continuous 50 discharge–charge cycles at a current density of 100 mA g−1. The proposed fast crystallization route provided a versatile, facile and fast method for the synthesis of functional metal oxide nanomaterials with controllable sizes and composition.