The application of carbon dots in electrolytes of advanced batteries

Abstract

In response to the growing demand for renewable energy, rechargeable batteries, such as lithium-ion batteries, are finding increasingly widespread applications in energy storage and daily life. Currently, the pursuit of batteries with high specific energy and enhanced safety is constrained by limitations in the electrolyte bulk and interfacial reactions. Consequently, modulating the electrolyte and its interphases is key to overcoming current bottlenecks and developing next-generation batteries. As an emerging nanomaterial, the rich surface functional groups and dopable sites of carbon dots (CDs) enable them to simultaneously regulate bulk ion dynamics and interface stability through surface chemistry design, showcasing immense potential in addressing the critical challenges in electrolytes. This review systematically summarizes the cutting-edge applications of CDs in electrolytes for lithium-ion, sodium-ion, and zinc-ion batteries. It introduces the structural characteristics, classification, and synthesis methods of CDs, and outlines their multifaceted roles as additives in liquid electrolytes, fillers in solid-state electrolytes, and interfacial regulators for solid composite electrolytes. A special focus is placed on elucidating the mechanisms of CDs in regulating ion deposition, constructing functionalized interfacial layers, and optimizing the electrolyte microenvironment. Finally, this review discusses the challenges and future outlook for CDs in electrolyte engineering, aiming to provide new perspectives and theoretical support for the design of battery systems with high specific energy and high safety.