Function-oriented design of conjugated carbonyl compound electrodes for high energy lithium batteries

Abstract

Organic carbonyl compounds are potentially low-cost, sustainable, and high energy density electrode materials, but are plagued by unsatisfactory active-site utilization, low discharge potentials and low rate discharge–charge performance in battery applications. We herein disclose a function-oriented design of carbonyl compounds with multi-electron reactions as positive electrode materials for rechargeable lithium batteries, showing that molecular orbital profiles and energetics can be applied for the prediction of carbonyl utilization and modulation of redox potentials. By embedding pre-aromatic 1,2-dicarbonyl moieties in the extended conjugated systems, the desirable molecules integrate all known stabilizing factors and enable full four-Li uptake. Remarkably, two new carbonyl electrodes, pyrene-4,5,9,10-tetraone and 1,10-phenanthroline-5,6-dione, deliver a reversible capacity of 360 mA h g⁻¹ and an average working potential of 2.74 V, respectively, providing insights in designing high-energy organic positive electrodes of lithium batteries for efficient energy storage and conversion.