Sodium-Based Dual-Ion Battery: From Materials to Mechanism.

Sodium-based dual-ion batteries (SDIBs) have garnered increasing attention as a next-generation energy storage technology, owing to their high operating voltage, cost-effective raw materials, and environmentally friendly characteristics. These features position SDIBs as a compelling alternative to conventional lithium-ion batteries, particularly for large-scale applications. Despite significant progress in improving energy density and cycling stability, several critical challenges remain-most notably, the development of durable electrode materials and the formulation of electrolytes that are both efficient and compatible with the dual-ion mechanism. In this review, we provide a comprehensive overview of recent advances in SDIB research, with a particular focus on the design and optimization of electrode materials and electrolyte systems. We delve into the fundamental electrochemical mechanisms that govern the operation of SDIBs. In addition, we explore emerging concepts and innovative strategies aimed at addressing existing limitations, including aqueous SDIBs and quasi-solid-state SDIBs. By synthesizing the current state of knowledge and highlighting key research directions, we hope that the insights presented herein will inspire further innovation and accelerate the development of high-performance, sustainable SDIBs for future energy storage applications.