Organic batteries for a greener rechargeable world

The emergence of electric mobility has placed high demands on lithium-ion batteries, inevitably requiring a substantial consumption of transition-metal resources. The use of this resource raises concerns about the limited supply of transition metals along with the associated environmental footprint. Organic rechargeable batteries, which are transition-metal-free, eco-friendly and cost-effective, are promising alternatives to current lithium-ion batteries that could alleviate these mounting concerns. In this Review, we present an overview of the efforts to implement transition-metal-free organic materials as the redox-active component in diverse types of organic rechargeable batteries. In addition, we critically evaluate the current status of organic rechargeable batteries from a practical viewpoint and assess the feasibility of their use in various energy-storage applications with respect to environmental and economic aspects. We believe this Review provides a timely evaluation of organic rechargeable batteries from a real-world perspective, and we hope it will spur more intensive efforts towards a greener energy future.