Molecular Design\nStrategy toward Multielectron-Based\nPolyphenylaniline Organic Cathode and Its Electrochemical Performance

The growing demands for electronic devices and electric\nvehicles\nrequire the exploration of more efficient and high-power battery systems,\nin which the organic cathode materials are becoming a research hot\nissue in energy storage batteries. In the work, a polytriphenylamine\nderivative of polyphenylaniline (P(PhAn)) with a polyaniline-like\nmolecular backbone structure was prepared by Buchwald-Hartwig C–N\ncoupling reaction, and its electrochemical performances were evaluated\nin detail as the lithium organic cathode material. P(PhAn) as cathode\ndisplayed the multielectron redox characteristic, in which two pairs\nof redox characteristic peaks occurred in the measured voltage range.\nDensity functional theory (DFT) calculation and simulations further\nproved that the formed push–pull electron effect and the conjugated\npolyaniline-like skeleton change the redox potentials and electron\ntransfer of the cathode material. The electrode material also exhibited\nstable cycling performances and superior rate performances. It has\na decent initial discharge specific capacity of 133 mAh·g<sup>–1</sup>, and after the 100 cycles, it kept at 111.2 mAh·g<sup>–1</sup>, remaining the 86% of capacity retention compared\nto the second cycle. Under the current densities of 20, 50, 100, 200,\nand 500 mA·g<sup>–1</sup>, it displayed the discharge\nspecific capacities of 124, 122.1, 119.5, 115.3, and 112.4 mAh·g<sup>–1</sup>, respectively, and a 90.6% of capacity was even remained\nat the rate of 500 mA·g<sup>–1</sup>. Furthermore, it\nwas proved that the energy storage process for P(PhAn) was mainly\ncontrolled by a capacitive-diffusion hybrid kinetics process.