Novel Organic Positive Electrode Materials for a New Generation of Greener Batteries : Design and Electrochemical Properties

The necessity to integrate renewable electricity both on and off-the-grid, coupled with eagerness of the electric automotive industry and electronic manufacturers, have markedly increased the need for high-performance and affordable electrochemical generators, particularly the rechargeable ones. Consequently, the world production of secondary batteries is expected to keep on growing. However, most common electrode materials are based on inorganic materials obtained from non-renewable resources and synthesized by ceramic route. To fulfil the actual market demands as well as the emerging environmental concerns, there is a need to design better but also “greener” battery technologies. Along that line, the implementation of Organic Electroactive Materials (OEMs) could be perceived as one of the possible alternatives. Switching from metal-based compounds to organic structures may offer several potentialities and environmental benefits including first the possibility to alleviate the pressure on scarce metals currently used by the battery industry. Indeed, organic molecules are composed of quite naturally abundant chemical elements (e.g., C, H, N, O). From an electrochemical point of view, the multiplicity of chemical combinations at the molecular level gives rise to an incomparable tool for adjusting the redox potential of conjugated systems. Over the past 5 years, beyond redox-active polymers, different interesting organic host structures have been identified by several groups notably based on carbonyl-containing cyclic structures. However the development of efficient and reliable organic batteries is clearly in its early stage. One significant issue of organic electrode materials is their tendency to dissolve in common liquid electrolytes used in batteries. Another limitation lies in the difficulty in finding robust positive electrode materials. This communication will be an opportunity to present recent advances in the field especially in terms of poorly soluble organic cathode materials capable of being reversibly charged at a high enough potential.