Electrochemically Fabricated Polypyrrole-Cobalt-Oxygen Coordination Complex as High-Performance Lithium-Storage Materials

Current lithium-ion battery (LIB) technologies are all based on inorganic electrode materials, though organic materials have been used as electrodes for years. Disadvantages such as limited thermal stability and low specific capacity hinder their applications. On the other hand, the transition metal oxides that provide high lithium-storage capacity by way of electrochemical conversion reaction suffer from poor cycling stability. Here we report a novel high-performance, organic, lithium-storage material, a polypyrrolecobaltoxygen (PPy-Co-O) coordination complex, with high lithium-storage capacity and excellent cycling stability. Extended X-ray absorption fine structure and Raman spectroscopy and other physical and electrochemical characterizations demonstrate that this coordination complex can be electrochemically fabricated by cycling PPy-coated Co3O4 between 0.0 V and 3.0 V versus Li+/Li. Density functional theory (DFT) calculations indicate that each cobalt atom coordinates with two nitrogen atoms within the PPy-Co coordination layer and the layers are connected with oxygen atoms between them. Coordination weakens the C?H bonds on PPy and makes the complex a novel lithium-storage material with high capacity and high cycling stability.