New organic electrode materials for lithium batteries produced by condensation of cyclohexanehexone with p-phenylenediamine

Abstract

The redox-active materials based on the condensation product of cyclohexanehexone with p-phenylenediamine (PTDA) were synthesized. The effect of the reactant ratios (1: n, n = 1, 2, 3) on the morphology and electrochemical properties of the resulting polymers PTDA1-PTDA3 was analyzed. In the case of PTDA3, a regular network crosslinked by CN-C bonds is formed resulting in a significant increase in the practical capacity of this material from 160 to 285 mAh g−1 corresponding to a three-electron redox process. Quantum-chemical modeling was performed to clarify the peculiarities of the lithiation mechanism. It is shown that the best sites for lithium cation coordination are adjacent oxygen and nitrogen atoms or two nitrogen atoms. For all polymer structures, sequential redox lithiation-delithiation processes have been established.