Conjugated Carbonyl Compounds as High-Performance Cathode Materials for Rechargeable Batteries

In search for novel cathode materials for lithium, sodium, and potassium ion batteries, organic electrode materials are expected to be the next powerful candidates owing to their high theoretical capacity, facile synthesis, low cost, and structural diversity. However, reports concerning organic compounds are not common compared to those concerning inorganic compounds in both research and commercial applications. New requirements for rechargeable batteries, such as low production cost and natural abundance, also preclude us from focusing on heavy and toxic metals, which still impose cost and resource constraints. Undoubtedly, organic carbonyl compounds featuring multielectron reactions and reaction reversibility are quite suitable for meeting these needs. In this review, an overview of the recent efforts on carbonyl materials containing small molecules and polymers is provided. In addition, some strategies to resolve the main problems, such as the dissolution of active organic chemicals into organic electrolytes, low discharge voltage, and low electronic conductivity, are discussed.