The concept of high entropy for rechargeable batteries

The development of revolutionary rechargeable battery technology is essential for achieving a carbon-neutral society. Despite significant progress in diverse rechargeable batteries over the past decades, electrochemical stability, ionic/electronic conductivity, reaction rates, crystal phase stability, etc. remain major challenges. The concept of high entropy has emerged as a new approach to addressing diverse scientific and engineering challenges of rechargeable batteries by virtue of its unique properties. This review aims to provide a timely and comprehensive understanding of the properties, development, and applications of high entropy materials/strategies in rechargeable batteries. The fundamental concepts of high entropy, including high entropy materials, high entropy doping/substitution, high entropy stabilization, high entropy interlocking, high entropy liquids, etc. are introduced. The state-of-the-art development of high-entropy concepts in rechargeable batteries, including Li/Na/K/Zn-ion batteries, Li-S batteries, Li-O₂ and Zn-air batteries, covering anode materials, cathode materials, liquid electrolytes, solid electrolytes, and catalysts are systematically introduced, with an emphasis on the role and principles of high entropy in solving specific scientific/engineering problems. Their unique properties and functions for battery applications are summarized, and challenges and opportunities of high entropy concepts for rechargeable batteries are also proposed to promote the development of this intriguing field.