Lithium Salt of Tetrahydroxybenzoquinone: Toward the Development of a Sustainable Li-Ion Battery

Abstract

The use of lithiated redox organic molecules containing electrochemically active C═O functionalities, such as lithiated oxocarbon salts, is proposed. These represent alternative electrode materials to those used in current Li-ion battery technology that can be synthesized from renewable starting materials. The key material is the tetralithium salt of tetrahydroxybenzoquinone (Li₄C₆O₆), which can be both reduced to Li₂C₆O₆ and oxidized to Li₆C₆O₆. In addition to being directly synthesized from tetrahydroxybenzoquinone by neutralization at room temperature, we demonstrate that this salt can readily be formed by the thermal disproportionation of Li₂C₆O₆ (dilithium rhodizonate phase) under an inert atmosphere. The Li₄C₆O₆ compound shows good electrochemical performance vs Li with a sustained reversibility of ∼200 mAh g⁻¹ at an average potential of 1.8 V, allowing a Li-ion battery that cycles between Li₂C₆O₆ and Li₆C₆O₆ to be constructed.